Triannual Unionid Report

Report No. 14

March, 1998

A forum for the informal exchange of information on the status of
North American unionid research, management, and conservation

Thanks to
Andrew Lydeard, Tuscaloosa, Alabama and
Becky and Caleb, Putnam County, Tennessee for the mussel art.

Richard G. Biggins
U.S. Fish and Wildlife Service
160 Zillicoa Street
Asheville, North Carolina 28801

NOTE: The intent of this report is to expedite the exchange of information in an
informal format. Report submissions were solicited from individuals and
agencies involved in unionid conservation. The submissions were not edited.
They were copied as received and assembled into the report.
The report was then scanned to create this Web site.

TABLE OF CONTENTS
TRIANNUAL UNIONID REPORT NO. 14
MARCH 1998

National Native Mussel Conservation Committee
Announcement of the 3rd National Freshwater Mussel Symposium to be held March 17-19, 1999, Chattanooga, Tennessee

Watson, S.N., Jr.
Lillard Mill mussel survey, 1997

Anderson, B.
Possible impact of river otter (Lutra canadensis) on muskrat (Ondatra zibethicus) and mussel populations in selected Tennessee streams

Havlik, M.E.
One year follow-up of a unionid mollusk translocation from an area with a moderate infestation of Dreissena polymorpha (Pallas, 1771), Mississippi River mile 725.8, T.H. 43 Bridge, Winona, MN/WI

Metcalfe-Smith, J.L., G.L. Mackie, S.K. Station, and E.L. West
Current status of rare species of freshwater mussels in Southern Ontario

Hubbs, D.
Commercial mussel regulations: Tennessee

Ahlstedt, S.
Mussel poster produced depicting 48 native mussels of the upper Clinch River, Tennessee and Virginia

Watson, B.T., and R.J. Neves
Fish host identification for two federally endangered unionids in the upper Tennessee River drainage

Hove, M.C., and J.E. Kurth
Darters, sculpins, and sticklebacks serve as suitable hosts for Venustaconcha ellipsiformis glochidia

Watters, T.G.
New publication: 1998. The trouble with zebras. Timeline, Ohio Historical Society 15(2):32-41

Watters, T.G., and S.H. O'Dee
New publication: 1998. Metamorphosis of freshwater mussel glochidia (Bivalvia: Unionidae) on amphibians and exotic fishes. American Midland Naturalist 139:49-57

Watters, T.G., and S.H. O'Dee
Potential host for the washboard, Megalonaias nervosa (Rafinesque, 1820)

Watters, T.G., and S.H. O'Dee
Continuing saga of Anodonta woodiana

Drees, L.
Mussel speakers wanted

Dunn, H.L.
Recent unionid studies by Ecological Specialists, Inc.

Araujo, R., S. Jimenez, and M.A. Ramos
Reproduction in captivity and glochidial development of Margaritifera auricularia (Spengler, 1793) in Spain

Badra, P., and M.M. White
Conservation of a unionid (Lampsilis siliquoidea)

Barnhart, M.C., and A.D. Roberts
The effect of temperature, CO2 and pH on the transformation success of glochidia of fish hosts and in vitro

Berg. J.B., and S.I. Guttman
Genetic structure of unionid populations: Implications for captive propagation and reintroduction

Blalock, H.N., J.D. Williams, and D.N. Shelton
Historical and current distribution of the freshwater mussels (Unionidae and Margaritiferidae) of the Escambia and Yellow River drainages of southern Alabama and Western Florida

Blodgett, K.D., J.A. Stoeckel, S.D. Whitney, and R.E. Sparks
A dynamic population model as a tool for evaluating mussel management strategies

Chen, L.Y., A.G. Heath, and R.J. Neves
Physiological effects of transportation in water and in air on freshwater mussels (Unionidae)

Christian, A.D., and D.J. Berg
Community and population characteristics of unionid assemblages in the headwaters of the Big Darby Creek basin, OH

Cordeiro, J.R.
Distribution and habitat of Colorado freshwater mussels (Mollusca: Bivalvia: Unionidae)

Cummings, K.S., A E. Bogan, S.A. Bruenderman, T.J. Frest, R.G. Howells, T. Muir, D.G. Smith, G.T. Watters, and J.D. Williams
North American freshwater mussels: Distribution, biology, and conservation

Dimock, R.V., Jr.
Oxygen consumption by juvenile Pyganodon cataracta in declining PO2 (Bivalvia: Unionidae)

Dimock, R.V., Jr., R.A. Tankersley, and M. Whitton
Effect of commercial algal preparation on growth and survival of juvenile Pyganodon cataracta and Utterbackia imbecillis (Bivalvia: Unionidae)

Ferris, J.L., C.D. Milam, and J.L. Harris
Relocation and subsequent evaluation of condition for adult mussel populations relocated to hatchery refugia

Gatenby, C.M., M.A. Patterson, B.C. Parker, and R.J. Neves
Filtration rates over 24 h for adult rainbow mussels (Villosa iris, Lea 1829) held in culture

Gatenby, C.M., M.A. Patterson, B.C. Parker, P. Morrison, and R.J. Neves
A protocol for the salvage and quarantine of mussels from zebra-infested waters

Hallac, D., and J.E. Marsden
Differences in tolerance to and recovery from zebra mussel (Dreissena polymorpha) fouling by Elliptio complanata and Lampsilis radiata

Havlik, M. E.
External aging of unionids revisited: Height versus age of 4800 Megalonaias nervosa (Rafinesque 1820), Mississippi River reaches (Pools) 9-19, Lansing, IA-Fort Madison, IA, 1 July-14 September 1997

Hoggarth, M.A., D.L. Rice, and T.L. Grove
The correlation of mussels with fish in the upper Blanchard River in Hardin and Handcock Counties, Ohio, with special regard to the rayed beam (Villosa fabalis)

Hove, M.C., K.R. Hillegass, J.E. Kurth, V.E. Pepi, C.J. Lee, P.A. Mahoney, A.R. Kapuscinski, and M. Bomier
Considerations for conducting host suitability studies

Howells, R.G.
Reproductive seasonality of freshwater mussels (family Unionidae) in Texas

Hubbs, D.
Practical propagation of freshwater mussels for shell harvest

Keller, A.E., N.J. Kernagham, and L. Straub
Seasonal changes in respiration, cholinesterase activity and glycogen stores in three species of unionid mussels

Kenyon, R., K. Welke, P. Thiel, T. Naimo, and E. Monroe
Survival and growth of unionids after relocation into an artificial pond

Khym, J.R., J.B. Layzer, and J.M. Redding
Efficacy of cortisol administration to induce glochidial metamorphosis

King, T.L., M.S. Eackles, R.F. Villella, and B. Gjetvag
Discontinuity in the genetic population structure of freshwater mussels: Conservation implications

King, T.L., R.F. Villella, M.E. Smith, and P.I. Washington
Conservation of freshwater mussel species: A tissue repository for genetic and systematics

Kloeck, R.
1997 unionid surveys in the Fox River and Springbrook Creek, Illinois

Lellis, W.A., and C.S. Johnson
Experiences with captive maintenance of Atlantic Slope unionids in small research systems

McClane, M.B.
Mississippi River precision brailing: Utilizing GPS, GIS and the Internet

Milam, C.D., J.L. Ferris, M.L. Barfield, J. Van Hassel, and L.A. Locum
Reintroduction of native freshwater mussels into a recovering stream using both in viro and in vitro propagation techniques

Monroe, E.M., and T.J. Naimo
Effects of relocation on physiological condition of Amblema plicata plicata

Myers-Kinzie, M., and A. Spacie
Non-destructive glochidial harvest and artificial transformation of Lampsilis siliquoidea: A suitable species for glochidial and juvenile research

Nedeau, E.J., M. Kaufman, and R.W. Merritt
Digging deeper to solve the missing mussel mystery

Neves, R.J., F.X. O'Beirn, B.B. Beaty, and M.B. Steg
The survival and growth of freshwater mussels in a recirculating aquaculture system

Nichols, S.J., and D. Garling
Food web dynamics of Unionidae in a canopied river and a non-canopied lake

Nichols, S.J., G. Black, and J. Allen
Feasibility of using microhabitat selection to provide in situ protection of unionid populations from the impact of zebra mussels

O'Brien, C.A.
Reproductive biology for four mussel species of the Gulf Coastal Plain

O'Dee, S.H., and G.T. Watters
New and confirmed host identification for ten freshwater mollusks

Parker, B.C., M.A. Patterson, and R.J. Neves
Feeding interactions between native freshwater mussels (Bivalvia: Unionidae) and zebra mussels (Dreissena polymorpha) in the Ohio River

Patterson, M.A., C.M. Gatenby, B.C. Parker, and R.J. Neves
Ingestion and assimilation of 14C labeled algae by the freshwater mussel, Villosa iris (Lea, 1829)

Patterson, M.A., B.C. Parker, and R.J. Neves
Glycogen levels of unionids during starvation and controlled feeding in quarantine

Quinn, R. D., and J. B. Layzer
Extreme variation in survival rates of mussels during a 30-day quarantine period

Riusech, F.A., and M.C. Barnhart
Host suitability differences among Venustaconcha ellipsiformis (Bivalvia: Unionidae) from different river drainages

Ruessler, D.S., and A.E. Keller
Survival of juvenile unionid mussels cultured under several food and water regimes

Schwartz, M.L., and R.V. Dimock, Jr.
Ultrastructural analysis of changes in the marsupial demibranch during brooding of glochidia in Pyganodon cataracta and Utterbackia imbecillis (Bivalvia: Unionidae

Schwegman, J.E
Lure behavior in Toxolasma texasensis

Seal, U.S.
Conservation of threatened mussel species as a multiple stakeholder process

Shadoan, M.K., and R.V. Dimock, Jr.
Differential sensitivity of hooked and hookless glochidia to chemical and mechanical stimuli

Smith, D.G.
Investigations of the byssal gland in juvenile unionids

Starkey, R.W., A.G. Eversole, T.E. Schwedler, D.E. Brune, G. Schwartz, and J.A. Collier
Growth and survival of juvenile and adult freshwater mussels in the partitioned aquaculture system

Starliper, C.E., R. Villella, P. Morrison, and J. Mathias
Preliminary studies on the potential bacterial pathogen contagion between freshwater mussels and salmonid fish

Tankersley, R.A.
Fluorescence techniques for evaluating the lipid content of larval and juvenile mussels

Tankersley, R.A., and S. Butz
Design, construction, and evaluation of a laboratory-scale recirculating aquaculture system for the captive care of freshwater mussels

Tankersley, R.A., M.G. Wieber, K. Kachurak, and S. Butz
Use of condition indices, protein biomarkers, and RNA:DNA ratios for detecting nutritional stress in freshwater unionid mussels

Villella, R.F., W.J. Bartles, and D.A. Weller
Freshwater mussel (Elliptio complanta) movement and condition with relation to temperature, flow, and substrate type

Waller, D., M. Bartsch, S. Jennings, H.L. Dunn, W.G. Cope, and R. Rada
Conservation of unionid mussels in the St. Croix River: Development in situ refugia

Watters, G.T., and S.H. O'Dee
Glochidial release as a function of water temperature

Welke, K., R. Kenyon, T. Naimo, E. Monroe, and P. Thiel
Logistic considerations in the relocation of unionids into artificial refugia

Westbrook, O.J., and J.B. Layzer
Survival and growth of hatchery-reared juvenile Lampsilis cardium

Wicklow, B.J., and P.M. Beisheim
Life history studies of the squawfoot mussel Strophitus undulatus in the Piscataquog River watershed, New Hampshire



National Native Mussel Conservation Committee

Announces the
3rd National Freshwater Mussel Symposium
"Musseling in on Biodiversity"
hosted by
The Southeast Aquatic Research Institute
and
The Tennessee Aquarium
March 17 th- 19th 1999
at the
Clarion Hotel
407 Chestnut Street
Chattanooga, Tennessee

The National Native Mussel Conservation Committee (NNMCC) announces the 3rd National Freshwater Mussel Symposium will be held on March 17-19, in Chattanooga Tennessee. The meeting will be similar in format to the Conservation and Management of Freshwater Mussel meetings held in St. Louis, Missouri in 1992 and 1995. The theme of this symposium will be freshwater mussel biodiversity. Like the earlier meetings, this symposium will focus on status surveys, life histories, habitat requirements, biology, techniques, etc. in both oral and poster presentation formats. In addition to the freshwater mussel presentations, there will be a special session dealing with the conservation of freshwater gastropods. As with the previous meetings, a proceedings will be published. A call for papers will follow in the fall of 1998. Scientists, researchers, conservation agency personnel, federal and state biologists with an interest in freshwater mollusks are encouraged to participate. Current meeting information will soon be available on the Southeast Aquatic Research Institute web site at http://www.sari.org , or call Paul Johnson at (423) 7854074.

Lillard Mill Mussel Survey, 1997

Charles N. Watson, Jr.
Aquatic Resources Center
4410 Peytonsville Road
Franklin, TN 37064
Phone: 615-790-0172
Fax: 615-790-0173
E-mail: aquatres@ix.netcom.com

In August 1997 Aquatic Resources Center performed a mussel survey at Lillard Mill on the Duck River for TWRA. The purpose of this survey was to determine the density, distribution and population demography of the unionid fauna with emphasis on the endangered species Lemiox rimosus, Epioblasma capsaeformis and Quadrula intermedia. Lillard Mill is of particular interest because it harbors one of the last sizable populations of L. rimosus. Previous surveys were made in 1993, 1994 and 1995.

Sampling occurred along 24 transects, 12.5 m apart. Ten quadrats were randomly selected on each transect. All mussels in a transect were enumerated and identified. Lemiox rimosus, E. capsaeformis and Q. intermedia were measured, sexed and aged.

A total of 23 species and 965 individuals was found. Mean density was 16.1/m2. These figures compared favorably with those from previous surveys (21 - 25 species, 17.7 - 15.1/m2). The five most abundant species in 1997 were Cyclonaias tuberculata - 253 (26.2%), Elliptio dilatata - 131 (13.5%), Lemiox rimosus - 93 (9.6%), Truncilla truncata - 88 (9.1%), and Quadrula pustulosa - 76 (7.8%). Cyclonaias tuberculata ranked first in all previous surveys. Elliptio dilatata ranked seventh in 1993 and has steadily increased in rank. Lemiox rimosus has fluctguated in rand (1993 - 5th, 1994 - 3rd, 1995 - 6th). Truncilla truncata declined, having consistently ranked second in all previous surveys. Quadrula pustulosa also declined in rank, having been fourth in previous surveys.

Lemiox rimosus ranged in age from 2 - 15 years. There were 59 males, 23 females and 11 juveniles. At least one individual was found on every transect. Epioblasma capsaeformis ranged in age from 3 - 10+ years. There were 7 males, 9 females and 2 juveniles. Epioblama numbers have been increasing (1993 - 0, 1994 - 5, 1995 - 11) but remain low. Only two Quadrula intermedia were found. One was 10+ years old, the other was too eroded to age. No attempt was made to sex them. Previously, on Q. intermedia was found in 1995, and none in 1993 and 1994.

Few muskrat middens were found in 1997. This contrasted with 1995, when several large middens were found at the site. Sixteen L. Rimosus and four E capsaeformis were found in middens in 1997. In 1995, 638 L. rimosus and 8 E capsaeformis were recovered from middens.

The mussel population at Lillard Mill appears to be healthy. Many species, including the endangered L. rimosusand E capsaeformisare reproducing, as evidenced by the presence of juveniles and gravid females. Runoff from the access road and parking area is a potential threat. A large silt plume was observed following a heavy rain during sampling. We recommend that steps be taken to minimize runoff at Lillard Mill.

Possible impact of river otter (Lutra canadensis) on muskrat (Ondatra zibethicus) and mussel populations in selected Tennessee streams

Bruce Anderson
Tennessee Wildlife Resources Agency, 218 Genesis Road, Crossville, TN 38555
(931)484-9571, banderson@mail.state.tn.us

The river otter (Lutra canadensis),once endemic statewide in Tennessee, was largely extirpated over much of the state in the early 1900's (Toweill and Tabor, 1982). Muskrats (Ondatra zibethicus) remained indigenous to most, if not all streams in the state and were known to feed on resident mussels where those were available. Muskrats were considered a normal part of the ecosystem and were not considered to have an unusually detrimental impact on mussel populations. However, evidence of significant changes in muskrat densities resulting from otter restoration may indicate a need to examine the otter/muskrat/mussel interrelationship more closely.

Reintroduction of the river otter in Tennessee began in 1984 with the release of six otters into the Obed Wild and Scenic River. At the time of otter release, the Obed sustained an abundant muskrat population. Muskrat "middens," composed mainly of mussel shells, were common on the river. By 1986, Dean Bryson, a local trapper who trapped along the Obed, reported a decline in muskrat numbers there. Subsequent observations revealed a steady and ultimately, enormous decline in the occurrence of muskrat sign, primarily middens, on the Obed. Similar observations have been made on other streams, including the Big South Fork of the Cumberland River and the Hiwassee River, after otter reintroduction (Steve Bakaletz, US Park Service, Big S. Fork NRRA; Jim Herrig, US Forest Service, Cherokee National Forest).

While virtually all research encompassing food habits of river otter suggests that small mammals constitute only a small percentage of otter diet (Toweill and Tabor, 1982), no research assessing the impact of otter presence on muskrat densities can be found. Some otter food analysis was conducted using scats from otter released on the Obed (Griess and Anderson, 1987), and the Great Smokey Mountains National Park (Griess, 1987; Miller, 1992). No muskrat remains were found in any scat collected. However, these samples were small and were undertaken as an incidental addition to the primary research and were not designed to assess impact of otters on muskrats.

Analysis specifically aimed at assessing otter impact on the muskrat populations in the above streams is now impossible since prerelease muskrat population levels cannot be determined. However, research to determine such impact would be useful given the field observations noted above. Otter extirpation may have resulted in an abnormal rise in muskrat populations, possibly adversely affecting resident mussels. Conversely, reintroduction of river otter may serve as a significant natural control of muskrat populations, thereby enhancing survival of mussels.

Literature cited:
Griess, J.M., and B.F. Anderson. 1987. Reintroduction of river otter into the Obed Wild and Scenic River in Tennessee. Proc. 3rd S.E. Non-game and Endangered Wildlife Symposium. Ga. Dept. of Natural Resources. Pp 167-175.

Griess, J.M. 1987. River otter reintroduction in Great Smokey Mountains National Park. M.S. Thesis. University of Tennessee, Knoxville. 109 pp.

Miller, M. C.1992. Reintroduction of river otters into Great Smokey Mountains National Park. M.S. Thesis. University of Tennessee, Knoxville. 58 pp.

Toweill, D.E., and J.T. Tabor. 1982. The northern river otter. Pages 688-703 in J.A. Chapman and G.A. Feldhamer, eds. Wild mammals of North America: biology, management, and economics. The Johns Hopkins University Press, Baltimore, Md.

One year follow-up of a unionid mollusk translocation from an area with a moderate infestation of Dreissena polymorpha (Pallas, 1771), Mississippi River mile 725.8, T.H. 43 Bridge, Winona, MN/WI

HAVLIK, MARIAN E., Malacological Consultants, 1603 Mississippi Street, La Crosse, WI 54601-4969. Phone/Fax: 608-782-7958 E-mail: havlikme@aol.com

A mussel translocation from this site, September 1996, yielded 6199 unionids (23 species, mean density 1.88/m2) in a primarily sand substrata. No federally listed unionids were found but 2% represented seven Minnesota and Wisconsin endangered, threatened and special status species. Most of 80 Obovaria olivaria(Rafinesque 1820) were juveniles. Ellipsaria lineolata(Rafinesque 1820) (1), Pleurobema sintoxia(Rafinesque 1820) (4), Ligumia recta(Lamarck 1819) (12), and Utterbackia imbecillis(Say 1829) (11), were also represented by juveniles. Other special status species were Arcidens confragosus(Say 1829) (2), and Megalonaias nervosa(Rafinesque 1820) (2). On 18 September 1997 quantitative and random sampling at the translocation site showed an overall survival of 93.77% of the translocated unionids. Spring 1997 high water apparently caused changes in the river since 5-7.5 cm of sand had accumulated over much of the sand, gravel, and mud substrata we found at the translocation site in 1996. Most of the living unionids were nearly buried in packed sand. The mean density of hash-marked common unionids from 32-0.25 quadrats was 4.25/m2 and included 11 of the 23 translocated species. The density of unmarked unionids was 17.25/m2. Besides marked unionids in quadrats, and 38 (of 112) numbered and 185 hash-marked unionids were found during random searches for a 1997 total of 241 live and 16 dead marked unionids (N = 257) from the translocation site. Twelve unmarked special status unionids were among 600 unmarked unionids identified during follow-up; included were Arcidens confragosus(1), Pleurobema sintoxia(5), and Obovaria olivaria(6). Of the 38 numbered unionids, two were dead for a survival of 94.74% of the special status species. Both at this translocation site, and at a similar translocation site near La Crosse, WI, the species that seems to be most affected by translocation is Ligumia recta. We have the impression that this species might do better if it were just placed on the substrata, rather than being planted, since there was no other obvious cause of the mortality rate seen for that species (2 of 4 numbered specimens were dead at this site). Hove (1997) reported seeing L. recta lying on the substrate. Many special status unionids, particularly young Obovaria olivaria(Rafinesque 1820), clearly showed growth, both after the 1996 translocation (evidenced by a false rest or interruption ring) and again in 1997 with another 5 mm of growth after the usual winter rest ring. There is good recruitment and growth of a number of species at the translocation site in spite of obvious impacts from spring high water. Only small numbers of Dreissena polymorphawere found. This exotic species does not appear to have seriously impacted this translocation site, possibly because of the predominantly sand substrata and the number of juvenile unionids involved in this project.

Current status of rare species of freshwater mussels in Southern Ontario

Janice L Metcalfe-Smith1*, Gerald L. Mackie2, Shawn K. Staton1 and Emma L. West1.
1National Water Research Institute, P.O. Box 5050, 867 Lakeshore Road, Burlington, ON L7R 4A6;
2Department of Zoology, University of Guelph, Guelph, ON N1G 2W1. *PH: 905-336-4685; FAX: 905-336-4420; Email: Janice.Smith@cciw.ca

Nearly half of the 40 species of freshwater mussels native to the Canadian waters of the lower Great Lakes drainage basin are presently ranked as very rare (S2), extremely rare (S 1) or known from historical records only (SH) by the Natural Heritage Information Centre in Peterborough, Ontario. In this study, we determined the current conservation status of 21 species believed to be at risk in Ontario. Most of these species have severely declined in the Great Lakes themselves due to the impact of the zebra mussel (Dreissena polymorpha). The last refugia for many of Canada's native mussel species are the Grand, Thames and Sydenham Rivers in southwestern Ontario. Thirty-seven sites on these rivers that historically supported the target species were intensively surveyed during the summer of 1997 to determine the true status of these species. Current data on species distributions from this and other recent (post-1990) surveys on these rivers were combined and compared with the historical data to determine if there have been changes over time. The major findings of this studyare as follows:

We successfully located more living species on all three rivers than other recent surveyors, due to our greater sampling effort. However, we still observed species losses: 27%, 41% and 24% of the species known from the Grand, Thames and Sydenham Rivers, respectively, according to historical records dating back to the late 1800s, were not found alive in 1997. Although 30 of the 36 species previously known from the study area were found alive, 13 of these species now occur in fewer rivers than they did in the past, i.e., their ranges have been reduced. The Sydenham River still supports the richest and most productive mussel community of any small river in Canada, with 25 living species, an average diversity of 13 species/site, and an average abundance of over 150 individual mussels/site based on a sampling effort of 4.5 person-hours. In 1992, Arthur H. Clarke urged "...that the Sydenham River be made an ecological preserve and that its fauna be protected by legislation." To this, we would add that time is of the essence.

The conservation status of 21 species of freshwater mussels was assessed by comparing the current (post-1990) distribution of each species with its historical distribution. On the basis of these comparisons, changes to the official conservation status ranks (Ontario's SRANKS) of 11 species were proposed. Three species currently ranked SH were found alive and could therefore be downlisted to S1 (Epioblasma torulosa rangiana, Obliquaria reflexa and Torolasma parvus). As the persistence of Simpsonaias ambigua is highly likely due to the presence of fresh shells at many sites, this species was also tentatively downlisted to S1. Five species appear to have declined significantly (Fusconaia flava, Ligumia nasuta, Pleurobema coccineum, Truncilla donaciformisand Villosa iris)and are therefore recommended for uplisting. Two other species (Cyclonaias tuberculataand Truncilla truncata)were more common than expected, and could be downlisted. We recommended that 11 species with current or proposed ranks of S1 be given first consideration for national status designation by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), as measures will have to be taken soon to prevent their extirpation. These species are: E. t. rangiana, O. reflexa, S. ambigua, T. parvus, Lampsilis fasciola, Obovaria subrotunda, Ptychobranchus fasciolaris, Utterbackia imbecillis, Villosa fabalis, T. donaciformisand P. coccineum. The authors have been commissioned by COSEWIC and COSSARO (Committee on the Status of Species at Risk in Ontario) to prepare status reports on three of these species (Epioblasma torulosa rangiana, Lampsilis fasciolaand Villosa fabalis). During this study, a conservation status score system was devised for identifying and prioritizing areas of prime mussel habitat that should be protected. This system may be a useful tool for agencies that are responsible for managing the water and habitat quality of Ontario's rivers. This research was partly funded by the Endangered Species Recovery Fund.

Commercial mussel regulations: Tennessee

Don Hubbs, P.O. Box 70, Camden, Tennessee 38320
TNMussel@aol.com, New Fax: # (901) 584-8548

TWRA fish division personnel in conjunction with the mussel advisory board have conducted regular public meetings for the past four years. These meetings have been a forum for the exchange of information between TWRA and the mussel industry. Since March of 1996, much of the discussion has centered around the unification of mussel shell size limits for the major shell producing states of Alabama, Arkansas, Louisiana, Kentucky, Tennessee and Texas. Because of the illegal trafficking of undersized shells from other states into Tennessee, parity of shell size limits was defined as the number one priority at a meeting held in Nashville in March 1996. This meeting was hosted by TWRA, with 13 states and four shell companies attending. Tennessee is the only state that has yet to pass a proposal that conforms to the established minimum shell size limits. At the June 1997 mussel advisory board meeting, TWRA informed the mussel industry of its intention to propose an increase in shell size limits. Much of the ensuing comments dealt with the economic impact this would have on the shell harvester. Finally, a proposal was put forth by a shell diver to increase the size limits one-sixteenth inch per year to reach the proposed minimum size limits. Since the June meeting, TWRA has met Twice in Bowling Green, H with Kentucky Department of Fish & Wildlife and the shell industry. A joint proposal has been developed between the two state to reach the new minimum size limits and already passed by Kentucky. The size increase schedule is as follows: Washboard Mussel (currently 3 3/4") - 3 13/16" for 1998, 3 14/16" 1999, 3 15/16" 2000, and 4" in 2001 and thereafter, Lake Shells (Threeridge, mapleleaf, pigtoe etc. currently 2 5/8") - 2 11/16" for 1998, and 2 3/4" thereafter, ebony and monkeyface shells will remain at 2 3/8"; threehorns will become legal at 1 3/4".

This proposal was presented to the Tennessee Wildlife Resources Commission (TWRC) during its January meeting at Reelfoot Lake. After more than one hour of public comment, the TWRC deferred voting on the proposal until its next meeting to be held at the Legislative Plaza in Nashville, February 25th and 26th. The vote was deferred at the request of 74th district State Representative Mr. John Tidwell. Representative Tidwell requested the deferral so that he could further study the need for this proposal. TWRA's Fish Division met with Representative Tidwell , explained in detail the necessity of this regulation. After this meeting, Mr. Tidwell stated that "he thought the size limits should remain the same...but it would be good if the proposal passed."

The proposal was presented for the second time at the February TWRC meeting in Nashville, and subsequently deferred for one year.

Mussel poster produced depicting 48 native mussels of the upper Clinch River, Tennessee and Virginia

Steven Ahlstedt, U.S. Geological Survey, 1820 Midpark Drive, Knoxville, Tennessee 37921
(423) 545-4140 or 545-4141 (Ext. 17), Fax: (423) 545-4496, Ahlstedt@usgs.gov

In collaboration with Dr. Paul Parmalee, McClung Museum, University of Tennessee, we are in the final stages of a color poster on the mussels of the upper Clinch River, Tennessee and Virginia. The poster will feature 48 native mussels (7 showing sexual dimorphism) and the Asian clam. Both common and scientific names and federal status are included along with a paragraph concerning mussel conservation. The poster was funded by the U. S. Fish and Wildlife Service (Regions 4 and 5), The Nature Conservancy (Virginia and Tennessee Chapters), Virginia Department of Game and Inland Fisheries, Virginia Department of Conservation and Recreation, Tennessee Wildlife Resources Agency, and Tennessee Valley Authority. Posters will be distributed throughout the upper Clinch River to schools, businesses, 4-H clubs, city community buildings, and local, state, and federal agencies.

Fish host identification for two federally endangered unionids in the upper Tennessee River drainage

Authors: Brian T. Watson1 and Richard J. Neves2
Address: Virginia Cooperative Fish and Wildlife Research Unit
  Department of Fisheries and Wildlife Sciences
  Virginia Polytechnic Institute and State University
  Blacksburg, VA 24061-0321
Phone: (540) 231-57031, (540) 231-59272
Fax: (540) 231-7580

Fish hosts were identified for the federally endangered dromedary pearlymussel (Dromus dromas) and birdwing pearlymussel (Lemiox rimosus) during 1997. A total of 31 fish species were tested as hosts for these mussels. The only host fish identified for the dromedary pearlymussel was the fantail darter. Thirty-four juveniles were collected from four infested fantail darters over a period of 18-25 days (average water temperature was 23.0oC). Examination of the gills of eight infested fantail darters that died, before transformation could occur, revealed the presence of approximately 265 encysted glochidia. Four additional percids also were identified as potential host fish; tangerine darter, gilt darter, banded darter, and logperch. In addition, the snubnose darter was identified as the second percid to serve as a host for the birdwing pearlymussel, with the greenside darter implicated as a host. Twelve juveniles were collected from two infested snubnose darters over a period of 20-32 days (average water temperature was 23.0oC). Five encysted glochidia were present on these two snubnose darters after they were sacrificed at 38 days post-infestation, indicating that the transformation period may be longer. The following table summarizes the results for all the fish species tested.

FISH SPECIES
Dromus dromas
Lemiox rimosus
Campostoma anomalum NSH X
Catostomus commersoni NSH X
Cottus carolinae NSH X
Cyprinella galactura NSH(?) X
Cyprinella spiloptera NSH(?) X
Erimystax dissimilis NSH(?) X
Erimystax insignis NSH(?) X
Etheostoma blennioides NSH POTENTIAL
Etheostoma camurum NSH(?) X
Etheostoma flabellare HOST NSH
Etheostoma rufilineatum NSH NSH
Etheostoma simoterum NSH HOST
Etheostoma stigmaeum NSH(?) X
Etheostoma vulneratum NSH NSH(?)
Etheostoma zonale POTENTIAL X
Hybopsis amblops NSH(?) X
Hypentelium nigricans NSH(?) X
Luxilus chrysocephalus NSH(?) X
Luxilus coccogenis NSH(?) X
Nocomis micropogon NSH X
Notropis leuciodus NSH(?) X
Notropis rubellus NSH(?) X
Notropis sp. NSH(?) X
Notropis telescopus NSH(?) X
Noturus insignis NSH X
Percina aurantiaca POTENTIAL X
Percina caprodes POTENTIAL X
Percina evides POTENTIAL NSH
Phenacobius uranops NSH(?) X
Pimephales notatus NSH X
Rhinichthys atratulus NSH(?) X

NSH = Non-Suitable Host; NSH(?) = Non-Suitable Host, although fish died before transformation;
HOST = Successful host; POTENTIAL - Fish died before transformation but glochidia still on gills;
X = Fish species not infested for that particular mussel species

Darters, sculpins, and sticklebacks serve as suitable hosts for Venustaconcha ellipsiformis glochidia

Mark C. Hove and Jennifer E. Kurth
Department of Fisheries and Wildlife University of Minnesota
1980 Folwell Avenue, St. Paul, MN 55108
(612) 624-3019, Mark.Hove@fw.umn.edu and kurt0007@tc.umn.edu respectively

Laboratory transformation studies have shown slimy sculpins and Johnny darters will facilitate metamorphosis of V. ellipsiformis glochidia (Hove and Anderson 1997).

Metamorphosis of V. ellipsiformis glochidia was observed on six of eight fish species tested (Tables 1 and 2) during this fall and winter. Between 40-80 juveniles were collected from aquaria holding brook sticklebacks, Iowa darters, fantail darters, and mottled sculpin. Only three juveniles were collected from logperch and three from blackside darters.

Table 1. Trials where V. ellipsiformis transformation observed.
Species
Number tested
Juvenile collection period (d)
brook stickleback 8 18-37
Iowa darter 8 18-30
fantail darter 8 18-35
blackside darter 4 30-34
logperch II 3 25-32
mottled sculpin I 4 19-36
mottled sculpin II 4 19-28
Average water temperature was 21 +- 2oC

Table 2. V. ellipsiformis transformation not observed.
Species
Number tested
Encystment period (d)
river darter 1 21-23
logperch I 8 18
logperch III 8 8-11
bluntnose minnow 8 5

Gravid females were collected from the Zumbro River, Minnesota in early November 1997. Mantle waving by gravid females in the laboratory observed in previous years (Hove and Anderson 1997) was not observed in four females held this year.

Funding and support for this study was provided by the Minnesota Department of Natural Resources - Natural Heritage & Nongame Research Program, Legislative Commission on Minnesota Resources, University of Minnesota - Undergraduate Research Opportunities Program, and Bell Museum of Natural History.

Literature Cited
Hove, M.C., and T.W. Anderson. 1997. Mantle-waving behavior and suitable fish hosts of the ellipse. Triannual Unionid Report. Report No. 11, p. 3.

New publications by T.G. Watters & Scott H. O'Dee

Ohio Biological Survey & Aquatic Ecology Laboratory
Ohio State University
1314 Kinnear Rd.
Columbus, OH 43212-1194
voice: 614-292-6180
fax: 614-292-0181
e-mail: gwatters@postbox.acs.ohio-state.edu

Watters, G.T. 1998. The trouble with zebras. Timeline, Ohio Historical Society 15(2):32-41

A popular article on zebra mussels. Neat photography by Gary Meszaros.

Watters, G.T., & S.H. O'Dee. 1998. Metamorphosis of freshwater mussel glochidia (Bivalvia: Unionidae) on amphibians and exotic fishes. American Midland Naturalist 139:49-57

Abstract. - This study determined that inexpensive and easily maintained amphibians and exotic fishes could act as hosts for two species of native North American unionid mussels, and bypass the need to identify native hosts when the object is to culture mussels. Two mussel species, Lampsilis cardium and Utterbackia imbecillis, were used to parasitize 42 exotic fishes and seven potential nonpiscine hosts. Nonpiscine hosts included amphibians and decapod crustaceans. Lampsilis cardium successfully metamorphosed on six species of exotic fishes, as well as on larval tiger salamanders. Utterbackia imbecillissuccessfully metamorphosed on 30 species of exotic fishes and all four amphibian species tested. No glochidia metamorphosed on crustaceans. Successful metamorphosis on amphibians indicates that mussel zoogeography may be more complicated than previously thought. Using surrogate hosts may be a valuable alternative to natural hosts in laboratory culture of mussels.

Potential host for the washboard, Megalonaias nervosa (Rafinesque, 1820)

T.G. Watters and S.H. O'Dee
Ohio Biological Survey & Aquatic Ecology Laboratory
Ohio State University
1314 Kinnear Rd.
Columbus, OH 43212-1194
voice: 614-292-6180
fax: 614-292-0181
e-mail: gwatters@postbox.acs.ohio-state.edu

Laboratory transformations occurred on the following species:
Largemouth Bass Longear Sunfish Bluegill
Longnose Gar Yellow Perch  

And to a much lesser extent on:

Logperch Slenderhead Darter Central Stoneroller

The following fishes did not act as hosts:

Banded Darter Variegate Darter Bluntnose Minnow
Suckermouth Minnow Striped Shiner Rosyface Shiner
Sand Shiner Spotfin Shiner  

Continuing saga of Anodonta woodiana

T.G. Watters and S.H. O'Dee
Ohio Biological Survey & Aquatic Ecology Laboratory
Ohio State University
1314 Kinnear Rd.
Columbus, OH 43212-1194
voice: 614-292-6180
fax: 614-292-0181
e-mail: gwatters@postbox.acs.ohio-state.edu

In my article on this species in Veliger 40: 152-156, I mentioned a report by Ng et al. (1993) that state that Pseudodon vomdembuschianus (Lea, 1840) had been introduced to Singapore on exotic fishes. Dr. Chow Sow-Yan of Singapore kindly supplied me with specimens from the Lower Seletar Reservoir. As he suspected, these actually are Anodonta woodiana. They were introduced on carp and/or tilapia from hatcheries in Taiwan.

Ms. Stephanie Clark of New South Wales, Australia, recently sent specimens of a unionid from Laguna de Bay, Luzon Island, Philippine, collected in 1992. Laguna de Bay is the largest freshwater lake in the Philippines. The Philippines have no native unionids, but they now have Anodonta woodiana. The specimens were found at or adjacent to the Bureau of Fisheries at Tanay, Rizal Province.

Mussel speakers wanted

The National Native Mussel Strategy Outreach Committee is developing a volunteer "Native Mussel Speakers Bureau." Volunteers with a desire to share their expertise on all aspects of native mussels including the national mussel conservation effort are sought. The speakers list would be made available to state and federal agencies, conservation and sport organizations, schools, and museums. Unfortunately, funding is not available at this time to pay for travel expenses. The joy of saving mussels must be our compensation. If you are interested in participating on the National Native Mussel Conservation Volunteer Speakers Bureau please send you name and topic of interest to:
Linda Drees
315 Houston St. St. E
Manhattan, KS 66502
Phone: 785-539-3474X20, Fax: 785-539-8567
E-mail: Linda_Drees@fws.gov

[Please send name, address, fax, e-mail, phone, topic, and geographic scope you can lecture within]

Recent unionid studies by Ecological Specialists, Inc. Heidi L. Dunn
Ecological Specialists, Inc., 114 Algana Ct., St. Peters, MO 63376
Phone: (314) 447-5355 Fax: (314) 447-4101 email: ecologists@aol.com

St. Croix River I-94 Unionid Relocations,

ESI relocated over 8,500 unionids of 30 species from I-94 construction areas and over 14,000 unionids of 28 species from bridge demolition areas of the St. Croix River near Hudson, Wisconsin in 1994 and 1995, respectively. Federal endangered species (Lampsilis higginsi) and Wisconsin threatened (Quadrula metanevra and Tritogonia verrucosa) and endangered (Cumberlandia monodonta, Cyclonaias tuberculata, Ellipsaria lineolata, and Elliptio c. crassidens) species were marked by etching shells with a unique number and placed in grids for future monitoring. The remaining animals were marked and placed in an existing unionid bed upstream of the bridge. Animals relocated in 1994 were monitored in October 1994, August 1995, and June 1996 and animals relocated in 1995 were monitored in October 1995, June 1996, and June 1997. Recovery was over 70% and mortality was less than 10% after one year in both relocations.

St. Croix River Stillwater Bridge Unionid Relocation,

ESI relocated over 18,100 unionids of 25 species from the proposed bridge area; including nine individuals of Federal or Wisconsin protected species. Animals were relocated to areas with similar habitat and unionid communities. Most animals were distributed in a 6,000m2 area. Experimental grids were established to monitor effects of relocation on three common species, as well as protected species. Over 88% of common species and 60% of protected species were recovered, observed mortality was <3%, and most animals had grown one year following relocation (1997). Relocated and resident animals also will be monitored in 1998 to assess effects of relocation on recovery, mortality, and growth, and assess effects of increased density on the resident unionid community.

St. Croix River Unionid Refugia Relocation,

Large midwestern rivers once supported diverse unionid communities. However, many unionid species are now on the brink of extinction due to pollution, habitat modification, and zebra mussel infestation. The recent invasion of the zebra mussel is currently the most serious threat to unionid communities in many of our large midwestern rivers. Relocating unionids into hatcheries or smaller rivers, which may not be invaded by zebra mussels, is considered a possible means of saving endangered species. In 1996, 100 Lampsilis higginsi(Federally endangered) and 100 each of two common species (Elliptio dilatata and Quadrula pustulosa) were relocated from the lower St. Croix River to an area approximately 50 miles upstream. Flow, depth, substrate, and unionid communities vary between the areas. Unionids in both collection and relocation areas will be monitored for at least two years to determine if large river species can survive in a smaller river environment and whether an "in river" refugia is a viable alternative to maintaining unionids in artificial systems. High survival, growth, and evidence of reproduction were observed one year after relocation.

Wolf River Highway 29 Bridge Unionid Relocation,

Wisconsin Department of Transportation plans on building a bypass for Highway 29 around the city of Shawano. The bypass will cross the Wolf River in a section known to contain Epioblasma triquetra,endangered in Wisconsin. In July 1995, over 27,000 unionids were collected from construction impact areas and relocated to an area upstream. Methods used for relocation and monitoring were similar to those used in the St. Croix River. No mortality of E. triquetraand minimal mortality of other species was observed one month following the relocation. Recovery after one year was near 80% and mortality was less than 5%. Monitoring will continue through 1997.

Relocated Unionid Monitoring, Ohio River Mile 418.9,

In 1987 over 5000 unionids of 22 species were relocated from an area of potential impact on the Ohio River near Cincinnati, Ohio. Unionids were tagged, measured, weighed, identified and relocated to a recorded location. The relocated community was monitored for four years. Only 35% of the relocated animals were alive and within the relocation area in 1990, however growth was apparent in most species. Movement was related to substrate type and discharge. After 10 years (1997), only 6% of the animals appear to be alive and within the relocation area. However, movement in this area is considerable, due to the rocky nature of the substrate; 81% of the marked animals were found away from their initial location, some as far as 75ft. Mortality of marked animals was evident, particularly in 1997. Some mortality is probably natural, as many of the relocated animals were probably 25 to 30 years old in 1997, and some mortality is probably due to zebra mussel infestation.

Campbell's Island, Illinois. Unionid Relocation,

Illinois Department of Transportation plans on replacing the existing bridge which spans the side channel of the Mississippi River at mile 490.3 near Rock Island, Illinois. One of the richest unionid communities in the upper Mississippi River occurs in this river reach and previous surveys near the Campbell's Island bridge indicated 33 species occurred in the area, including Illinois and Federal threatened and endangered species. Unionids were relocated from construction impact areas to a unionid bed on the channel side of Campbell's Island in September 1997. Far fewer unionids were present in the area than original expected, possibly due to zebra mussel effects. Fifteen species were found and relocated, includingLampsilis higginsi(Federally endangered) and Ellipsaria lineolata(Illinois threatened). Endangered and threatened species were marked and placed in grids to facilitate monitoring of survival. Two grids with three common species were established to assess survival and growth of relocated animals. Relocated animals were inspected one month after the relocation and all animals were live. Monitoring will be conducted in 1998.

Ohio River Unionid Monitoring, Ohio River Miles 204.3 and 218.0,

Ohio Municipal Electric Generation Agency contracted ESI to conduct a systematic dive survey of two unionid beds, and monitor these beds before and during construction and following operation of the hydropower facility. Pre-construction monitoring was conducted in 1993 and 1994, construction began in 1995, and post-construction monitoring was conducted in 1995, 1996, and 1997. Over 5,000 unionids were qualitatively collected each year to estimate species composition and relative abundance within the beds. Quantitative samples were randomly collected in each bed to determine mean unionid density and juvenile to adult ratios for comparison among years. Unionid density did not differ among years, and C. stegaria was collected during 1994 and 1997 qualitative sampling. Data from qualitative and quantitative sampling will be compared with future monitoring data to evaluate possible hydropower impacts on unionid communities.

Unionid Monitoring Plan Development and Long-Term Monitoring, Elk River, West Virginia,

Wolfpen Knob Development Company proposes constructing and operating a mining complex in Braxton County, West Virginia adjacent to the Laurel Fork of Tate Creek. Tate Creek flows into the Elk River, which supports a diverse unionid community, including three Federally endangered species; Lampsilis abrupta, Epioblasma t. rangiana, and Pleurobema clava. U.S. Fish and Wildlife Service and West Virginia Department of Natural Resources are concerned the project may adversely impact unionids and required Wolfpen to develop a monitoring plan to assess mining effects on unionids. ESI surveyed the Elk River for unionids upstream and downstream of the mine site, selected suitable monitoring sites, and developed a monitoring plan. The plan was presented to and approved by resource agencies in 1996. Monitoring, using the scope of work outlined in the plan, was initiated in 1997. Density, species richness, and age structure were estimated for unionid communities at four sites; two upstream and two downstream of the mine. Pre-construction data will be used to estimate natural and sampling variability.

Ohio River Unionid Impact Assessment and Monitoring, Ohio River Miles 252.6 to 257.5,

ESI was contracted by Southern Ohio Coal Company to evaluate unionid communities upstream and downstream of Leading Creek; an Ohio River tributary receiving discharge from Meigs Mine. Unionids were surveyed using quantitative and qualitative diving techniques at three locations; one site upstream and two sites downstream of Leading Creek. Unionids were sampled a few weeks following discharge, and one, two, and four years following discharge. No unionid mortality was detected due to mine water release in the sampled areas.

Unionid and Fish Habitat Survey in the Mullet River, Wisconsin,

The State Historical Society of Wisconsin (SHSW) proposes reconstructing a water-powered sawmill at Wade House State Park, located in Greenbush, Wisconsin. Two unionid species, Venustaconcha ellipsiformis and Alasmidonta viridis, which are threatened in Wisconsin occur in the project area. Unionid and fish communities, and their habitat, were characterized in the Mullet River from downstream of Glenbeulah dam to Mullet Marsh to facilitate project design, impact evaluation, and mitigation development. Sampling was conducted between 15 and 31 July 1997. Alasmidonta viridis and V. ellipsiformis, and their reported fish host (Etheostoma nigrum) were collected throughout three isolated reaches of suitable habitat. The project is within the longest reach of suitable habitat. ESI worked with engineers at Woodward/Clyde and SHSW to develop a construction and operation plan that would serve the project purpose, yet minimally affect the stream and its biota. The impoundment needed to drive the sawmill turbines will be constructed to the side of the river to minimize in stream disturbance, fish passage will be provided around the dam structure, and a re-regulation pool downstream of the dam should dissipate the effects of flow pulses.

Straight River Unionid Mollusk Survey, Minnesota,

Northern Natural Gas Co. proposes replacing a pipeline that crosses the Straight River (Cannon River Drainage) in Steele County, Minnesota. The unionid fauna of the Cannon River Drainage includes the Minnesota threatened Pleurobema coccineum and Venustaconcha ellipsiformis,and Minnesota special concern species Elliptio dilatata, Lasmigona compressa, Lasmigona costata,and Ligumia recta. Because unionids could be affected by pipeline replacement, the unionid community was sampled near the proposed pipeline crossing and downstream, to determine if protected unionids were present. The results of this survey indicated that a unionid community, similar to the historic fauna of the river, exists within the stream reach that may be impacted by in-stream disturbance from pipeline construction. This community includes the Minnesota threatened V. ellipsiformisand P. coccineum. If drilling under the river is successful, no impacts on the unionid community are expected. If in-stream disturbance cannot be avoided, mitigative measures may be needed to reduce construction impacts.

Minnesota and Pomme de Terre Rivers Unionid Mollusk Survey. Minnesota,

The proposed Alliance Pipeline Project crosses the Minnesota River (LeSure and Nicollet Counties) and the Pomme de Terre River (Stevens County), Minnesota. Both rivers have diverse unionid faunas that include state protected species, and the Federally endangered Lampsilis higginsi historically occurred in the Minnesota River. Because unionids may be affected by pipeline replacement, unionid communities near the proposed pipeline crossings and downstream were sampled to determine if protected unionids occur in these areas. A depauperate unionid community exists within the river reach surveyed on the Minnesota River, which is likely due to the unstable sand that predominates the substrate. Only three live unionids were collected, and no live or freshly dead individuals of any protected species were found, therefore, pipeline construction should not affect protected unionids. The study area on the Pomme de Terre River, however, supports a well established unionid community that harbors up to ten species. One freshly dead shell of the Minnesota threatened Pleurobema coccineum was found at Site 1, indicating that the population within this river reach is probably small. Since P. coccineum was not observed in the vicinity of the proposed pipeline crossing, the Alliance Pipeline Project is not expected to affect this species. However, unionids were common at the proposed pipeline crossing and sites downstream, and may be affected by in-stream disturbance from pipeline construction.

Ohio River Pomeroy/Mason Bridge Unionid Assessment, Ohio River Miles 248.2 to 254.4.

The Ohio Department of Transportation proposes replacing a Ohio River bridge at Ohio River Mile (ORM) 251.3 near Mason, West Virginia and Pomeroy, Ohio. Two alternative corridors for the replacement of structure are being evaluated. ESI was contracted to document all recent unionid surveys between ORM 248.2 to 254.4 (5km above and below the bridge) and conduct a brail survey of three potential alternatives to assess project affects on unionids. Three different sites (13% of the study area) had been previously surveyed for unionids, and relatively diverse unionid beds occurred at two of the three sites. An established unionid community does not appear to exist at any of the alternatives. No unionids were collected by brail or along the riverbank within Corridor A, only two individuals of one species (Amblema p. plicata) were collected within Corridor B, and no unionids were collected from the corridor at ORM 249.6. Although a brail is an inefficient method of characterizing unionid communities, if a significant bed existed in these areas at least a few individuals should have been collected on most transects, and more than one species should have been observed. Since unionid communities do not appear to occur in the proposed corridors, neither alternative should affect protected unionids in this river reach.

Unionid Survey near Mississippi River Mile 467.4,

Harza Environmental Services is assisting a client with environmental permitting for a water intake in Pool 16 of the upper Mississippi River. The range of two Federally endangered species (Lampsilis higginsiand Potamilus capax), as well as, several species considered threatened or endangered in Illinois and Iowa includes this area. The study's objectives were to 1) characterize the community (i.e., species composition, age structure), 2) determine if protected species occur in the community, and 3) estimate the project's impacts on the community (particularly protected species). Sampling was completed on 10 and 11 September 1997. Unionids were present within proposed construction areas, however, diversity was low and Amblema p. plicatacomprised over 50% of the community. Ellipsaria lineolatawas the only species collected live that is protected in Illinois and Iowa. A diverse unionid community appears to occur in the downstream portion of the study area, which is heavily colonized by zebra mussels. The downstream area may be affected during construction by sedimentation and during operation by alteration in local hydrology.

Unionid Survey at a Proposed Water Intake on the Mississippi River. Near Alton. Illinois,

Illinois-American Water Co. proposes installing a water intake system upstream of the current facility on the Mississippi River (approximate River Mile 204.3), Madison County, Illinois. Historically at least 28 unionid species occurred in this reach of the Mississippi River, including the Federally endangered Potamilus capax, and Illinois protected Ellipsaria lineolata, Elliptio crassidens, Elliptio dilatata, and Simpsonaias ambigua.This study characterized the unionid community near the proposed construction location and downstream to determine if protected unionids occur in the area. This area currently does not appear to support a unionid community, as only the shells of eight species were collected. Leptodea fragilis was the only species represented by freshly dead shells; the remaining species were collected as weathered or subfossil shells. Given that habitat conditions within the study area are unsuitable for unionid colonization, and no unionids were found, construction and operation of the water intake and treatment discharge should not impact unionids.

Reproduction in Captivity and Glochidial Development of Margaritifera auricularia (Spengler, 1793) in Spain [GT]

Margaritifera auricularia was described by Spengler in 1793. Since then it has been found in several localities in Western Europe and North Africa, many of them as fossils, but no living specimens have been recorded in any place since 1917. In a recent survey of Spanish Rivers to inventory the European Habitats Directive (Directive 92143/CEE) freshwater species, we found a living population of this giant pearl mussel in a very ancient channel of the Ebro River. Timing and length of the glochidial release period at the natural habitat has been determined by collection of drift samples. We introduced sturgeons into the aquaria with gravid mussels, realizing that all mussels began to spawn. Immediately after releasing, the glochidia attached to the fishes gills. We excised the gill filaments of the sturgeons 1, 2, 3, 4, 5 hours and 2, 3, 5, 13, 34 and 60 days after the beginning of glochidia release. Histological and scanning samples of these gill filaments are being studied in order to investigate the encystment process and to find out the period that the glochidia need to complete their metamorphosis. However, up to now, no juvenile specimens have been found in the aquarium. We are also evaluating, by artificial infestation, the possibility that other fish species (native species) may be parasitized by the glochidia. This kind of results, including the ones from molecular studies currently in course, are the basis for subsequent application of species recovery plans and reintroduction policies.

Conservation Genetics of a Unionid (Lampsilis siliquoidea). [Poster]

Protein electrophoresis is being used to measure genetic variation and population differentiation in a Unionid mussel (Lampsilis siliquoidea)and three species of its fish hosts. Most Unionidae have a larval stage which are obligate parasites of fish. Adult mussels are sessile, thus any migration between populations must occur while larvae are attached to fish hosts. Barriers to dispersal and gene flow between fish populations are expected to act as barriers to Unionid dispersal and gene flow. The hypothesis that population differentiation in the Unionid mussel reflects the population differentiation of its fish hosts is being tested. Mussels and host fish were collected from five sites within the Raisin River drainage in southeast Michigan. Thus far, the products of 16 loci have been assayed for two mussel populations. Four of these are polymorphic (P = 0.25, H = 0.21). A description of the population genetics of the Unionidae and an improved understanding of the role of fish hosts in influencing genetic variation and population differentiation will enhance conservation and management of this declining group.

The Effects of Temperature, CO2 and pH on the Transformation Success of Glochidia on Fish Hosts and In Vitro [GT]

Low temperature is known to suppress irnrnune function in ectothermic vertebrates, including fish. Therefore, we hypothesized that low temperature might facilitate successful encystment and transforrnation of glochidia on fish hosts. The glochidia of the flat floater, Anodonta suborbiculata,are normally present on fish hosts from January through March, when water temperature is low. The percent transforrnation success of attached glochidia in laboratory infections on fish hosts (golden shiners) was statistically significantly higher at 10oC (67%) and 15oC (62%) than at 21oC (42%). In contrast, transformation success of glochidia in vitrowas significantly lower at 10oC (39%) than at 15oC (89%) or 20oC (93%). Thus, improved survival at low temperature on fish hosts does not appear to involve direct effects of temperature on the glochidia. These results are consistent with the hypothesis that immune suppression of fish hosts by low temperature enhances transformation success of this winter-breeding unionid species. We also tested the effects of CO2 and pH on transformation of flat floater glochidia in vitro. Transformation success was highest at the lowest pH tested (7.6) and the highest level of CO2 tested (5%). This result is consistent with previous studies of other species, but is puzzling, because the physiological pH of fish body fluids is higher (ca. 8.0) and the level of CO2 is much lower. Although most workers have incubated glochidia in 5% CO2, we found that transforrnation was reasonably successful (68%) without elevated CO2, provided that pH was kept low.

Genetic Structure of Unionid Populations: Implications for Captive Propagation and Reintroduction [JR]

Captive care, propagation, and reintroduction programs are often used by natural resource managers charged with protection of endangered species. Experiences with a variety of taxa show that such programs must consider the population genetic structure of target species to ensure long-term survival. We used allozyme electrophoresis to quantify genetic structure of several unionid species and compare relative amounts of within-population (w-p) and among population (a-p) genetic variation. W-p variation was lower in populations of Elliptio dilatata(average of 1.6 alleles/locus, 36% polymorphic loci, 12% heterozygosity) than in populations of Quadrula quadrula(2.1, 61%, 24%). Amblema plicata showed intermediate levels of w-p variation (2.0, 58%, 11. 1%). Allele frequency differences were relatively large among populations of E. dilatataseparated by short distances. Populations of Q. quadrulashowed no variation in allele frequencies over distances > 1000 km. At least two models of genetic structure are found in unionid populations. Model I species such as Q. quadrulaexhibit high levels of w-p genetic variation, while a-p variation is much lower. Model II species such as E. dilatata are characterized by low w-p variation and high a-p variation. Conservation of diversity in a Model I species requires that captive populations consist of large numbers of individuals from a given population, while conservation of a Model II species requires maintenance of separate stocks from a number of populations. Design of captive propagation, reintroduction, and translocation programs must account for genetic structure of target species.

Historical and Current Distribution of the Freshwater Mussels (Unionidae and Margaritiferidae) of the Escambia and Yellow River Drainages of Southern Alabama and Western Florida [Poster]

The Escambia and Yellow river systems were surveyed from 1990 to 1996 to determine the presence/absence of thirteen rare mussel species. Historical distributions were determined from over 700 museum records from 64 sites in the Escambia River drainage, and from 71 museum records from 11 sites in the Yellow River Drainage. These records date from the late 1800's to 1989. In the Escambia River Drainage, 36 (56%) of the historical localities were resurveyed, as well as 59 new sites. Twenty-eight of the 30 species historically known from the basin were found in the current survey. In the Yellow River Drainage, seven (64%) of the historical sites were resurveyed, as well as 71 new sites. Eleven of the 15 species historically known from the drainage were found in the current survey, and two species previously unreported, Utterbackia imbecillisand U. peggyae, were also collected. The rare mussels known from the basins, Anodontoides radiatus, Elliptio arctata, Fusconaia escambia, F. rotulata, F. succissa, Lampsilis australis, L ornata, Margaritifera marrianae, Pleurobema strodeanum, Strophitus subvexus, and Villosa choctawensis were found only at a few sites. Medionidus acutissimusand Ptychobranchus jonesi,historically known from both basins, were not found in the current survey. Future efforts will concentrate on resurveying the remaining historical sites.

A Dynamic Population Model as a Tool for Evaluating Mussel Management Strategies [Poster]

Today, management of commercially important mussel species is hampered by an inability to quantitatively assess cumulative impacts of natural and harvest mortality on populations of this economically and ecologically significant resource. Sound science-based management will benefit from a tool that combines data on current populations with knowledge of population dynamics to predict future conditions under various management scenarios, We developed a single-species dynamic population model for native mussels using Stella II software running on a personal computer. The model was developed using data for the threeridge mussel (Amblema plicata) from Reach 15 of the Upper Mississippi River at Rock Island, L, but it can be parameterized for other locations and species when pertinent data exist. Input parameters include initial density (number per m2), age-frequency distribution, growth rate, age at maturity, and ages-specific mortality rates. In our model, recruitment is density dependent and incorporates fecundity, sex ratio, density-dependent fertilization rate, and glochidial attachment, transformation, and survival rates. The model outputs standing stocks (numbers per m2) of different age classes over time. Our model allows harvest which can be regulated by minimum size (currently a common management practice), minimum density, maximum harvest rate (number per m2), assorted closure strategies (e.g., harvest once every 1, 5, 10, or 20 years), or various combinations of these. Model outputs include annual and cumulative harvest (numbers and pounds per m2). The model uses size-dependent price estimates to calculate dollar values for standing stocks and both annual and cumulative harvest.

Physiological Effects of Transportation in Water and In Air on Freshwater Mussels (Unionidae) [CC]

To determine the best method for transporting freshwater mussels, fifty specimens of each of five species:Elliptio complanata, Villosa iris,and Fusconaia ebena, Quadrula quadrula,and Amblema plicata were collected in the field and subsamples of each species were frozen in liquid nitrogen. The rest of the samples were divided into two groups: one group was placed in a water-filled, aerated tank; the other group was placed in coolers with wet burlap. At 6 hr intervals up to 24 hr, a subsample of each group was removed and frozen in liquid nitrogen. All samples were then stored at -81 oC until analyzed for physiological stress. The concentration of glucose and glycogen in the posterior adductor muscle, gill, and mantle were chosen for estimating stress caused by transportation. In V. iris,the glucose levels of those from both transportation modes increased in the mantle tissues for the first 12 hr, but those transported in water recovered gradually after 12 hr. For the remaining four mussel species, transportation in water did not result in elevations of glucose levels, but transportation in air did cause an increase of glucose in some tissues. For all five species, there were no significant changes of glycogen content during either transportation modes. Overall, the transportation in water was less stressful than that in air. However, for the tolerant species, transportation in air for a short-term period might be an economic and feasible way to transport mussels.

Community and Population Characteristics of Unionid Assemblages in the Headwaters of the Big Darby Creek Basin, OH [Poster]

The Darby Creek ecosystem has been designated a "Last Great Place" by The Nature Conservancy based on its high diversity of unionids. Investigation of community and population characteristics in this system will lead to greater understanding of unionid ecology and to more effective conservation. Unionids were collected using two sets of parallel transects at sites on Big Darby (BDC) and Little Darby (LDC) creeks. Transects were orientated parallel to stream flow with 2 m separating each member of a pair. The BDC site contained 12 species, 357 individuals, and had an H' of 1.9. The dominant taxa for this site were Strophitus undulatus, Lampsilis siliquoidea, Ptychobranchus fasciolarisand Elliptio dilatata. The LDC site contained 10 species, 271 individuals, and had an H' of 1.5. The dominant taxa for this site were E. dilatata, P. fasciolaris and Fusconaia flava. Two state-endangered species, Pleuroberna clavaand Quadrula cylindrica, represented by two individuals each, were identified from this site. A Community Similarity Index between the two sites of 0.571 indicated that these two communities were moderately similar. Based on external annuli counts, E. dilatata from BDC and LDC sites ranged from 2-10 and 2-11 years in age, respectively and P. fasciolarisfrom BDC and LDC ranged from 2-19 and 4-16 years in age, respectively. Analysis of frequency histograms of age cohorts indicated no difference in structure of BDC and LDC populations of E. dilatata or P. fasciolaris. This information will be useful in understanding dynamics of unionid populations from headwater streams.

Distribution and Habitat of Colorado Freshwater Mussels (Mollusca: Bivalvia: Unionidae) [Poster]

North America has the greatest diversity of freshwater mussels in the world, yet members of the superfamily Unionacea are one of the most highly threatened groups of organisms in the United States. Colorado represents the westernmost range of some plains species. Past diversity in Colorado included upwards of seven different species. This study hypothesizes the diversity of unionid bivalves in Colorado lakes and streams is in rapid decline both at the species and the population level. The cylindrical papershell, Anodontoides ferussacianus (Lea), was once the most common species in the state, but it is currently found only in a slow-moving foothills stream with sand/cobble substrate and a small foothills lake with high turnover and mud/cobble substrate. A single dead shell of Uniomerus tetralasmus (Say), the pondhorn, found in a southeastern plains lake with mud/clay bottom is the only recent evidence of the this species in Colorado. Anodonta grandis grandis Say, the giant floater, has maintained steady populations in Colorado plains reservoirs with hard, alkaline water, but no longer occurs in streams. Management of these species requires knowledge of the location of population sources, the status of those populations, the habitat conditions under which they exist, and a reintroduction program to prevent further decline. Potentially stable population sources include Boulder Reservoir, Cherry Creek Reservoir, Pueblo Reservoir, and Colorado Fuel & Iron Reservoirs 1-3 for A. g. grandis and Valmont Reservoir for A. ferussacianus. It is likely already too late for U. tetralasmu s as all former populations seem to have disappeared.

North American Freshwater Mussels: Distribution, Biology and Conservation [Poster]

One of the objectives of the National Strategy on the Conservation of Freshwater Mussels (Biggins et al. (1995) was to prepare an atlas of North American freshwater mussels. An organizational meeting was held 20-21 October 1997 in Arlington, Virginia attended by the above (minus B. Howells and T. Frest) to discuss the preparation of a book entitled "North American Freshwater Mussels: Distribution, Biology and Conservation." It will be a reference volume largely based on the Atlas of North American Freshwater Fishes by Lee et al. 1980 (North Carolina State Museum of Natural History). The goals of the meeting were to: 1) compile initial lists of regional coordinators, compilers and species to be included, 2) develop a draft format for the maps and an associated database of the data sources. 3) develop a budget, 4) target potential funding sources. and 5) develop a timetable for completion of the project. Authorship of the 20 entire volume would be the regional coordinators with the species compilers credited on the pages of individual accounts as was done in Lee et al. (1980). Each species account will include: a color photograph, common and scientific name (including author and date), original description citation, type locality, systematics, key characters, general distribution, habitat, biology, and conservation status. Appendices will likely include: state references, synonyms, and fish host(s). The layout will be similar to the fish atlas but will include a two page format for some species. Although a fully geo-referenced database and computer generated maps would be desirable, it is unlikely that such a project could be completed in a reasonable time frame. However, one of the goals is to compile the data in a GIS usable format for the future. Pre-formatted software (PC and Mac compatible) will be distributed to all compilers to document the source of the distributional data used. Exact locality data are desired (citing museum collection numbers) but previously published maps and other sources could be used if documented (i.e. all Missouri data from R.D. Oesch, 1995. Missouri Naiades: a guide to the mussels of Missouri).

Oxygen Consumption by Juvenile Pyganodon cataracta in Declining PO2 (Bivalvia: Unionidae) [MP]

The physiology of very young unionids is largely unstudied. Historically, the near impossibility of acquiring sufficient numbers of young mussels from the field precluded experimental investigation. Success with in vitro and in vivo transformation of glochidia larvae in the laboratory has been tempered by generally low survivorship and relatively poor growth of the resulting juveniles. As a result, except for work on nutrition, most physiological studies have been limited to toxicological analyses of 1-2 week old juveniles of very few species. My laboratory has characterized the tolerance of l-week old Utterbackia imbecillis and Pyganodon cataracta to thermal, acidic and hypoxic stress and the effects of temperature and PO2 on heart rate of 2-week old juveniles. Recently we were able to culture 31 P. cataracta for 24 weeks. Of these, 13 attained a mean length of 6.2 mm (range = 3.3-8.3) and mean wet wgt (including shells) of 27.3 mg, large enough to monitor Vo2 of individual animals using microrespirometry (1.0 ml chambers, Strathkelvin oxygen sensors). Although the pattern of response to declining Po2 varied among individuals, especially in respect to whether animals remained open and siphoning for the duration of an experiment, consistent data were acquired for 9 animals. Mean VO2 near full air saturation was about 0.086 ml O2 gm-1 hr-1. Juveniles exhibited moderate oxy-regulation from full saturation to PO2 ~30 mm Hg, a pattern that is consistent with that of adults. These results constitute the first data on respiratory physiology of such young freshwater mussels.

Effects of Commercial Algal Preparations on Growth and Survival of Juvenile Pyganodon cataracta and Utterbackia imbecillis (Bivalvia: Unionidae) [Poster]

Although commercially available algal diets, including spray-dried powders and concentrated microalgal pastes, have been used extensively by marine aquaculturalists to rear larval and juvenile shellfish, their application for culturing unionid mussels in captivity has been limited. We examined the growth and survivorship of newly transformed juvenile Utterbackia imbecillis fed spray-dried Schizochytrium and Chlorella, or a multialgae paste composed of Thalassiosira pseudonana, Skeletonemasp., Chaetoceros calcitrans and Isochrysis galbana. Ten days following transformation, juvenile mussels were assigned to one of five diets: Schizachytrium alone, Chlorella alone, multialgal paste alone, a 1:1:1 mixture of all three diets, and a starved (no algae) control. Although initial growth rates of mussels were similar among treatments, after 3-wks mussels fed Schizechytrium alone had significantly higher growth rates (shell length, 54.4 u wk-1) and survival (77.8%) than all other treatments. Longer-term experiments were conducted to compare growth rates of juvenile Pyganodon cataracta (2-wks post-transformation) reared on spray-dried Schizochytrium alone and in combination with fresh cultures ofChlorella vulgaris. Juvenile mussels were assigned to 3 diets, Schizochytrum, liveChlorella,and a 1:1 mix of both diets, plus silt. Only juveniles fed the combination ofChlorellaand Schizochytrium survived to 10-wks (17%). At the end of the experiment (22-wks), survivorship of juvenile Pyganodon cataracta on the combination diet was nearly 16%. Mussels reached a mean shell length of 5.3 mm, representing about a 12 fold increase, and had a mean growth rate of about 271 u wk-1.

Relocation and Subsequent Evaluation of Condition for Adult Mussel Populations Relocated to Hatchery Refugia [CC]

Evidence of zebra mussel (Dreissena polymorpha) impacts on native mussels is growing as the invasion extends to Arkansas' waterways. The Arkansas River experienced the greatest initial invasion, while zebra mussels are now distributed along navigable sections of the White River. The objectives of this study were to transfer viable, native mussel populations, absent of any attached D. polymorpha to a refugium in order to determine the functionality and effectiveness of spring-fed ponds and raceways to shelter at-risk populations. Another objective was to monitor the physiological adaptations of transferred populations into "closed" systems located at the Mammoth Springs National Fish Hatchery for a specific period of time. Twenty-seven species from the White River were collected in the fall of 1996 for transfer to the hatchery. After initial size and weight were measured, mussels were tagged, cleaned and inspected for infestation before being transferred to holding chambers. Mussels were held for a two-week quarantine period before establishing permanent residence in the ponds. Mussels collected in the fall of 1997 from the Ouachita River included twenty-nine species, and similar techniques for transfer and isolation were conducted. To date, survival and mortality have been monitored for the White River species following one year after transfer, and <30% mortality has occurred in these populations. Physiological indices have been established for these mussels using Amblema plicata as a surrogate species. Cellulolytic enzyme activity and glycogen content have been monitored as biomarkers of relative condition to help evaluate the current holding facilities as effective habitats for refuge of threatened mussel populations.

Filtration Rates Over 24 h for Adult Rainbow Mussels (Villosa iris, Lea 1829) Held in Culture [MP]

The success of propagation of unionids for stock enhancement and endangered species management depends on understanding the feeding ecology of these aquatic organisms. Most bivalves feed by filtering suspended material from the water. Unfortunately, little data exist for filtering rates of unionids. Thus, our specific research objective was to determine the amount of algae cleared from suspension by adult rainbow mussels over 24 h. From the clearance of suspensions, we estimated the filtering rate of this species under our culture conditions. Filtration rates were monitored and compared using repeated analysis of variance with a sequential profile to examine successive differences. We tested for the effect of shell length, time, and interaction between time and length on filtration rates. Not surprising, filtration rates are different for different sized animals. In addition, filtration rates change significantly over 24 h. Mussels, 37-52 mm in length, were fed 1 x 106 c/ mL. Little to no algae settled in our culture chambers. For all mussels, filtration rates varied between 14 and 280 mL/h in the first hour, and after 24 h, the filtration rates varied between 9 and 34 mL/h. Mussels appeared to feed (filter) furiously in the first 2 h, then filter at lower rates for several hours, begin feeding and then lowered their filtration rate again. From this study, we estimated that 1, 45 mm sized rainbow mussel cleared over 900,000 cells of algae in 24 h.

A Protocol for the Salvage and Quarantine of Mussels From Zebra-Infested Waters [CC]

In the summer of 1995, a quarantine facility was assembled on Middle Island, of the USFWS Ohio River Islands National Wildlife Refuge, that could accommodate the salvage of several thousand unionids from the zebra mussel-infested Ohio River. The facility was supplied by well water and equipped with 14, 500 L tanks, aerated by a 0.5 hp regenerative blower, and plumbed so each could be drained easily. Because no biofilters were installed, water was changed every 2 d. Protocols for the salvage and quarantine of unionids were developed by state, federal, and university biologists. Three thousand unionids of 6 common species were collected in 1995, and several hundred unionids in 1996 and in 1997. Unionids were scrubbed on site to remove zebra mussels, and transported in ice-cooled containers to the quarantine facility. Unionids were quarantined for a minimum of 30 d, reinspected for zebra mussels, and transported to pond refugia if uninfested. Unionids were fed 10 L of a dense algal suspension 3 times/week in 1995, starved in 1996, and then were fed 1 x 105 cells/mL twice/day in 1997. Survival in quarantine was over 95% in all three years; however, survival after one year in pond refugia was different for fed (94%) versus starved unionids (70%). Suggestions for salvage and quarantine of unionids include: keep unionids cool (<28oC) during handling, transport in ice-cooled containers or in aerated water supplied with food, check for zebra mussels every 7 d and minimize the quarantine period to less than 30 d, and feed unionids at 1x105 cells/mL twice daily. If possible, collect unionids during cool months, when metabolism is low and energy reserves are high prior to reproductive activity. ,

Differences in Tolerance to and Recovery from Zebra Mussel (Dreissena polymorpha) Fouling by Elliptio complanata and Lampsilis radiata. [MP]

Since their discovery in 1993, zebra mussels (Dreissena polymorpha) in Lake Champlain have colonized the shells of many native unionids. Periodically cleaning zebra mussels from unionids may be an effective conservation technique if unionids can recover from the stress induced by zebra mussels. Conservation efforts will need to target those species that are most vulnerable to fouling and subsequent energetic losses. Because glycogen is the primary energy store in many bivalves, a decrease in glycogen content indicates loss of fitness. As dreissenid-unionid mass ratios increase in Elliptio complanata from Button Bay Vermont, there is no evidence that glycogen levels decrease even with mass ratios as high as 1.25. In contrast, dreissenid-unionid mass ratios as low as 0.25 in Lampsilis radiata are correlated with a significant decline in glycogen content. Results are consistent with a higher mortality of L. radiata than E. complanata in wild populations. In a second experiment, 32 mussels from each species were collected from the mouth of Lewis Creek, cleaned of zebra mussels (mean mass ratio: 1.45 + or - 0.57) and returned to the creek. After 10 weeks, cleaned mussels and an equivalent number of heavily fouled mussels (mean mass ratio: 1.76 + or - 0.71) of each species were collected. Twenty E. complanata and L. radiata were also collected from the Lamoille River where zebra mussels are absent. Mean glycogen levels in heavily fouled populations of both species were lower than control levels while cleaned mussels did not differ from controls. Results suggest that heavily fouled E. complanata and L. radiata can recover glycogen levels if cleaned of zebra mussels.

External Aging of Unionids Revisited: Height versus Age of 4800 Megalonaias nervosa (Rafinesque 1820), Mississippi River Reaches (Pools) 9-19, Lansing, IA-Fort Madison, IA, 1 July-14 September 1997 [Poster]

The Shell Exporters of America (SEA) sponsored a commercial unionid mollusk survey on the Upper Mississippi River Mile 663.0-386.0, Reaches 9-19, with an emphasis on M. nervosa, using modified 0.25 m2 Surber samplers I designed. Over 20,400 unionids were processed (692 quadrats, 252 random dives). Over 4800 living M. nervosa were scrubbed, measured for height and length, and aged. Mean density/Reach ranged from 2.7-7.6/m2. Mean height/age class/Reach, and mean age/ height class/Reach show age does not equal size. Growth rates increase further downstream (south). Two 80 mm high specimens, 23 and 6 years of age, were from Lynxville, WI, and Dallas City, IL respectively. Commercial M. nervosa (101.6 mm ht) were 9-38 years of age. In most Reaches 2.4-10.8% (mean 7.8%) of a commercial bed is of legal height. The most legal unionids were found in the Sylvan Slough Sanctuary (18.5%) indicating little illegal harvest. The 6 year age class (N = 130) had the largest height range (65 mm), while the height of 118-21 year olds varied 37 mm. The mean difference of all height classes was 41 mm/class. Number/size class for M. nervosa showed bell curves, but every Reach showed a marked shift to the left with number/age class peaks usually between 10-13 years; this is likely the species' response to the mid-1980's die-off. 3.18% of M. nervosa were less than 50 mm (2-7 years) indicating that the Mississippi River may be near a low point in the breeding cycle for M. nervosa.

The Correlation of Mussels With Fish in the Upper Blanchard River in Hardin and Hancock Counties, Ohio, With Special Regard to the Rayed Bean (Villosa fabalis) [Poster]

The rayed bean, Villosa fabalis, is a state endangered species in Ohio. It is among the smallest unionids to occur in the Midwest and has always been considered a rare species wherever it is found. The species was being considered for listing as endangered by the U.S. Fish and Wildlife Service before that agency eliminated its Category 2 Candidate list. However, V. fabalis is one of the most abundant species of mussels in the upper Blanchard River above Findlay in Hardin and Hancock counties in northwestern Ohio. It is the third most common species in that reach of stream behind the spike, Elliptio dilatata, and the fatmucket, Lampsilis radiata luteola. The current paper reports on collections of fish and mussels from 11 stations in the upper Blanchard River. The mussel community of this reach is represented by 16 extant species while the extant fish community totals 36 species. Records for a total of 17 species of mussels and 45 species of fish have been recorded for this reach of the Blanchard River. It was observed that the mussel community changed dramatically from station to station in this river mostly as a consequence of habitat availability. It was found that the fish community changed as well. This paper will report on the correlation of fish species with mussel species within this reach of stream. The objective is to suggest some potential natural hosts for these mussels, and to provide a protocol for the management of V. fabalis in the upper Blanchard River

Considerations for Conducting Host Suitability Studies [GT]

A well-designed protocol is important for identification of glochidial host(s) and propagation of juvenile mussels. We conduct our studies in flow-through and static aquaria. Fish are infested with glochidia by pipetting glochidia onto gills or placing larger fishes in a bath with several thousand glochidia under vigorous aeration. Aquaria are siphoned and siphonate checked for presence of glochidia and juveniles three times a week. We have increased the survivorship of hosts and maximized juvenile mussel production by: (1) scrutinizing host fish welfare just before and during juvenile mussel excystment, (2) conducting studies in flow-through aquaria, and (3) keeping tanks free of excess food. We have improved juvenile mussel recovery by: (1) holding small host fishes in suspended nets, (2) recording presence of pre-metamorphosed juveniles, (3) washing siphonate, (4) cleaning juvenile collection sieve with a cloth, and (5) increasing the number of hosts tested. These techniques were important in identification of glochidial hosts for a variety of local mussels. Metamorphosis of V. ellipsiformis glochidia was observed on Percina maculata, Etheostoma exile, E. flabellare, and Cottus bairdi. Four of seven Ictalurids were found to be suitable hosts for Cyclonaias tuberculata glochidia. Of twelve fish species tested only the Ameiurus natalis facilitated T. verrucosa glochidia metamorphosis. Epioblasrna triquetra glochidia were exposed to four fish species and Percina maculata and P. caprodes served as hosts.

Reproductive Seasonality of Freshwater Mussels (Family Unionidae) in Texas [Poster]

Most historical reports of spawning and brooding periods for freshwater mussels (Unionidae) have focused on work conducted in central and northern regions of the United States and Canada. Comparatively little has been documented in southern states, particularly in drainages west of the Mississippi. From 1992 through 1997, Texas Parks and Wildlife Department conducted statewide surveys of unionid abundance and distribution in Texas. Collectively, from specimens obtained during these surveys, over 5,000 specimens of 40 species were examined for the presence or absence of eggs and glochidia in female marsupia. Taxa studied included both widely-ranging species like Amblema plicata, Megalonaias nervosa, and Pyganodon grandis as well as locally endemic forms like Quadrula petrina, Quadrula aurea, and Lampsilis bracteata. Some observations include species not covered in previous literature. Results of these examinations are presented.

Practical Propagation of Freshwater Mussels for Shell Harvest [JR]

Commercial harvest of freshwater mussel shell has grown into a multi-million dollar business in Tennessee. Shell harvest fluctuates from 1,500 to 4,000 tons annually according to market demand. Approximately 50% of the shells exported from the United States are harvested in Tennessee. This harvest feeds an industry that employs 2,000 to 3,000 people and produces revenues exceeding $60 million a year in Tennessee. Greater than 90% of Tennessee's mussel harvest is taken from Kentucky Reservoir on the Tennessee River. Intensive harvesting of freshwater mussels has routinely depleted areas of their legal sized commercial shell stocks. In most areas of the reservoir, mussel stocks are harvested almost immediately after attaining legal size. Natural rep - u on require, expelled glochidia to attach themselves to a proper host, normally a fish. Most studies have indicated that infestation rates of wild fish are very low; however, through artificial propagation, heavy infestations can be obtained on nearly 100% of exposed fish. Because of the continued demand for mussel shells and the tenuous position of the resource, TWRA began experimenting with techniques for propagating commercial mussels during 1994. Objectives include identifying practical methods for augmenting commercially valuable mussel populations within selected Tennessee waters. Primary species employed in propagation procedures are the washboard (Megalonaias nervosa) and the threeridge (Amblema plicata plicata). Over 5,000 fish have been infested and released back into the reservoir since 1994. Juvenile A. p. plicata were recovered from a site where infested fish were held in a cage.

Seasonal Changes in Respiration, Cholinesterase Activity and Glycogen Stores in Three Species of Unionid Mussels [MP]

Glycogen stores, respiration rate and excretion were assayed once a month for twelve months in adult Utterbackia imbecillis, Elliptio icterina and Lampsilis teres mussels collected from the Suwannee River, FL. These species were selected because they have different habitat preferences, were locally abundant and had different reproductive cycles. Glycogen was found at the highest concentrations in the mantle and was lowest in the gill. E. icterina mussels contained the largest stores of glycogen overall and the highest adductor muscle cholinesterase activity of the three species. U. imbecillis, the fastest growing, thin-shelled member of the group had the highest respiration rate, followed by L. teres.

Survival and Growth of Unionids After Relocation Into an Artificial Pond [CC]

We evaluated the suitability of hatchery ponds as temporary refugia for unionids as a result of the zebra mussel invasion in the Upper Mississippi River (UMR). We compared the growth and survival of unionids between a hatchery pond and an in situ riverine control; among four holding options (treatments) in each location; and among species. Five species of unionids (Amblema plicata, Fusconaia flava, Leptodea fragilis, Obliquaria reflexa, and Quadrula quadrula) were obtained from the UMR, cleaned of zebra mussels, quarantined, and allocated into one of four replicates of each treatment (n=96 per treatment). Treatments included mesh bags, corrals, buried trays, and suspended trays. Survival, after 2.5 years of relocation, averaged 36% in the hatchery pond and 80% in the riverine control. In the riverine control, survival was substantially reduced in the corrals, but similar among the three other treatments. In the hatchery pond, survival was highest in the suspended trays and lowest in the mesh bags. Survival also varied among species, with highest survival in Quadrula and Amblema and lowest survival in Leptodea. Little or no new shell material was produced by mussels in the hatchery pond, whereas some growth was evident in the riverine control. These findings suggest handling and transportation stress did not adversely affect the short-term survival of unionids, because survival exceeded 80% during the first 2.5 years in the riverine control. In contrast, the poor survival in the hatchery pond suggests that these mussels were not receiving adequate nutritional resources.

Efficacy of Cortisol Administration to Induce Glochidial Metamorphosis [GT]

Host specificity of glochidia is believed to be immunologically based. Cortisol is a corticosteriod produced by teleost fish during stress. Prolonged elevations of cortisol can have an immunosuppressive effect on fish. Results from recent research have demonstrated the ability to induced glochidial metamorphosis on certain cortisol-treated nonhost fish. Our objective was to test the efficacy of administering cortisol to induce glochidial metamorphosis using a readily obtainable fish, largemouth bass Micropterus salmoides. Cortisol-injected night crawlers Lubricus terrestris were fed to largemouth bass prior to infesting the fish with glochidia of Potamilus alatus or Medionidus conradicus. Although this treatment successfully elevated plasma cortisol levels (>21ug/100ml), glochidial metamorphosis did not occur on these nonhost fish in two trials. Further, cortisol treatment did not have a significant effect (P>0.05) on how long glochidia remained attached to the gills. In a third trial, cortisol was orally administered to largemouth bass, a reported host of Ligumia recta. Metamorphosis of L. recta glochidia occurred on two of four cortisol-treated largemouth bass, and on two of six untreated fish. Juvenile metamorphosis was highly variable within and among treatments. Plasma cortisol levels of largemouth bass were not correlated (P>0.05) with juvenile mussel production. These results suggest that cortisol treatment is not an effective means to induce glochidia metamorphosis on largemouth bass.

Discontinuity in the Genetic Population Structure of Freshwater Mussels: Conservation Implications [Poster]

Molecular genetics has recently achieved an important place in contemporary conservation biology. It has proven to be a robust tool for identifying reproductive isolation among populations, permitting the delineation of management units and allowing assessment of conservation priorities from an evolutionary perspective. BRD recently funded nucleotide sequence analysis of the first internal transcribed spacer region (ITS-I) between 5.8S and 18S ribosomal DNA genes in Lasmigona subviridis representing the entire range of the species. Results indicate considerable genetic differentiation (including the absence of gene flow) between L. subviridis inhabiting the Susquehanna-Potomac Rivers and more southerly distributed populations. Similar levels of genetic differentiation have been observed in mitochondrial DNA in all freshwater mussels studied to date including the cytochrome oxidase I subunit in Alasmidonta heterodon and the 16S rRNA region in Megalonais nervosa, Amblema neislerii, and A. plicata. It appears that freshwater mussels are subdivided into more or less distinct genetic units. Knowledge of this structure is of major importance both for management and conservation of genetic resources. If it becomes necessary to culture the species targeted by conservation programs, sufficient numbers of viable individuals should be used as broodstock to eliminate inbreeding depression and the drift of alleles out of the population. Moreover, it is imperative that geographic populations of species targeted by such programs be segregated in holding facilities until such time genetic structure among populations is determined. This precaution is necessary to prevent the occurrence of outbreeding depression, hybridization, and disease transmission.

Conservation of Freshwater Mussel Species: A Tissue Repository for Genetics and Systematics [Poster]

The continuous decline of native North American freshwater mussels underscores the need for genetics research to determine population structure for conservation and management. Knowledge of mussel taxonomy is such that identification of species, subspecies, or distinct populations can often be problematic. Recognizing a need for phylogenetics research, the Aquatic Ecology Laboratory of the Leetown Science Center established a tissue repository and associated database to coordinate tissue samples collected for genetics and systematics research. The repository provides a centralized location to obtain properly catalogued and preserved adductor muscle, mantle, foot, gill and digestive gland tissue samples. All samples are preserved for both protein and DNA analyses. Data generated for the repository are maintained in the PARADOX for Windows relational database package. Collection information for each specimen includes date, site name, site description, and habitat characteristics. Reports of database content are generated and provided to interested researchers. Currently the database contains 388 individuals representing 53 species inhabiting the Atlantic Slope and interior basin drainages. Researchers utilizing the repository are required to accommodate a standard numbering scheme to allow comparisons of the same individuals among diverse studies and methodologies. Potentially, the repository would conserve precious resources by reducing the number of animals sacrificed and provide comprehensive data to multiple researchers. A single collection of mussels can provide ecophenotypic, protein, DNA, and immunological information for species and population structure delineation. This poster describes the development of the repository and presents data collection protocols, preservation methods, database structure, and a report of the database contents.

1997 Unionid Surveys in the Fox River and Springbrook Creek, Illinois

Illinois unionid mussels are declining rapidly in almost all waterways including Lake Michigan. Exotic zebra mussels are quickly colonizing many northeastern Illinois waterways and decimating native mussels. This three-year project will document and map two important native mussel populations, one of which may soon come under attack from zebra mussels. Focus areas will include the lower Fox River in Kane County and Springbrook Creek in DuPage County, which has the highest biodiversity of any remaining county stream. The project includes an outreach program about the Fox River for Kane County schoolchildren, as well as well as investigating the potential for cleaning zebra mussels from unionids in-situ as a means of zebra mussel control.

Experiences With Captive Maintenance of Atlantic Slope Unionids in Small Research Systems [CC]

Seven species of Atlantic slope unionids have been maintained in captivity for up to 3 years for use in reproductive and behavioral research. Mussels are housed in one of four culture systems that use either rectangular glass (120-240 l), rectangular fiberglass (540 l), or circular fiberglass (350 l) tanks. Tanks are supplied with well water heated or chilled within the range of 0.5-23.0,oC and illurninated with timer-controlled overhead lights to simulate natural seasonal fluctuations. Riverine species are provided mixtures of sand and gravel for substrate whereas pond species are provided with silt. Water current is established and regulated using airstones at the end of rectangular tanks and at the center of circular tanks. Mussels are batch-fed twice daily with one or more foods that may include cultured phytoplankton (Nanochloropsis sp.), detritus siphoned from concrete fish ponds, commercial preserved algal paste (Chlorella vulgaris), or bacteria collected from biofiltration units of recirculating fish culture systems. One-year survival varied with species, culture system, experimental treatment, and incidence of fatal mishaps, with an average 97% Elliptio complanata, 91% Alasmidonta marginata, 83% Alasmidonta undulata, 83% Pyganodon cataracta, 78% Lasmigona subviridis, 72% Strophitus undulatus, and 71% Alasmidonta varicosa. Three-year survival of Elliptio complanata has ranged from 20-80% with most mortality occurring in the third year. Elliptio complanata have spawned and produced viable glochidia within captivity. All other species have produced live glochidia, but fertilization may have occurred prior to capture. Development and testing of culture methods in ongoing with emphasis on water quality, diet and feeding, substrate, and metabolic and behavioral indices of unionid health.

Mississippi River Precision Brailing: Utilizing-GPS, GIS and the Internet [Poster]

The U.S. Army Corps of Engineers requested a brail survey be performed within specific areas above and below Mississippi River Locks and Dams 20, 22, 24 and 25. Numerous areas were located in the middle of the river with few landmarks readily available. Corps' ArcView GIS base maps depicting specific areas to be surveyed were downloaded via the Internet. Navigational waypoints were selected from these base maps using GPS software. Navigation to brail transect start and end points was