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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Unionid Ecology
SEDIMENT PREFERENCE AND BYSSAL THREAD PRODUCTION OF THE ENDANGERED RAYED BEAN (VILLOSA FABALIS) (BIVALVIA: UNIONIDAE) IN THE SYDENHAM RIVER, ONTARIO, CANADA.
D. Woolnough and G. Mackie. Department of Zoology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
The Sydenham River in southwestern Ontario hosts an abundance of rare aquatic species, including the Endangered Rayed Bean, Villosa fabalis. This study examines the distribution of the Rayed Bean and its production of byssal threads in relation to microhabitat variables (water depth, velocity, shell size and sediment particle size) in the Sydenham River. We found the population of the Rayed Bean is much larger and is distributed over a larger stretch of the Sydenham River than historically recorded. Also, the majority of adult Rayed Beans produced byssal threads throughout their life, not just in the juvenile stage. The sediment survey indicates that the Rayed Bean occurs in areas dominated by gravel and sand. One of the main distribution factors may be the occurrence and/or distribution of the fish hosts for the Rayed Bean. Using artificial culture propagation methods to identify fish hosts, we were able to transform glochidia into juveniles of the Rayed Bean on four fish species: mottled sculpin (Cottus bairdi), greenside darter (Etheostoma blenniodes), rainbow darter (Etheostoma caeruleum) and largemouth bass, (Micropterus salmoides).
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