Freshwater mussels are in decline, with over 70% of North American species categorized as endangered, threatened or of special concern. In an effort to create a nonlethal protocol for health evaluation of freshwater mussels we conducted a series of investigations on wild and captive populations of Elliptio complanata. We tested a method for nonlethal hemolymph collection and found no growth or survival effects in 30 sampled animals relative to 30 controls. We surveyed unionid populations from 19 different stream reaches from a rural region of North Carolina to provide a set of baseline ranges for hemolymph composition in healthy populations. These parameters included hemolymph calcium, magnesium, phosphorus, cell count, glucose, aspartate aminotransferase (AST), ammonia and protein. We tested these parameters in a captive population held under relatively uniform conditions and found most stable over time. Delta 15N declined substantially over time in captivity, likely in response to a large change in environmental _15N signatures. We tested health parameters in three groups of Elliptio complanata after three months under low, moderate or high feed conditions. The treatment groups varied in hemolymph glycogen, magnesium, calcium and phosphorus concentrations and in foot tissue _15N and _13C, providing possible indicators of subtle change in nutritional condition. We also transplanted Elliptio complanata from a stream enriched in _15N-N03 to a relatively depleted stream and evaluated the lag time required for mussel nitrogen isotope signatures to reflect new environmental signatures. We found a slow turnover time but relatively little variability compared to water signatures, suggesting that bivalves may be useful indicators of chronic nutrient loading in rivers and streams. We conclude that, with further research, hemolymph can be a valuable and safe tool for assessment of freshwater mussel population and habitat health.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-01032003-130125 |
| Date | 03 February 2003 |
| Creators | Gustafson, Laura L |
| Contributors | Richard Linnehan, Jay Levine, Michael Stoskopf, Tom Kwak, William Showers |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-01032003-130125/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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