| Popis: |
In North America 72% of freshwater mussel species are endangered, threatened, or of special concern due to factors such as habitat loss and degradation, biological invasion, and land use change. Propagation of freshwater mussels has been considered a necessary conservation strategy for population restoration where threats have been mitigated but small population sizes limit population viability. Yellow lampmussel is a species of freshwater mussel that is endangered, threatened, or imperiled throughout its range; therefore, I evaluated laboratory techniques (probiotic supplements and secondary rearing designs) to improve culture of yellow lampmussel for population restoration. Several aquaculture facilities commonly use probiotics; thus, I used commercial probiotics to determine if 1) probiotic concentration and 2) type of probiotic mixture improved growth or survival of juvenile mussels during primary culture. I further asked whether probiotics affected mussels by reducing ammonia, thereby improving water quality. Some probiotics increased survival (and, in one experiment, increased growth) of juvenile mussels, regardless of concentration, but results were variable by experiment and probiotic type. Probiotics did not significantly reduce ammonia concentrations, so this was unlikely the mechanism of benefit. I also investigated the effect of different secondary rearing systems at two culture facilities on growth and survival of juvenile mussels in two size classes (5.0 mm). I used five different secondary culture systems that were either indoors (dogpans and baskets) or outdoors (trough, airlift upweller, tank upweller, baskets), where water was either recirculating or flow-through. Survival was exceptional in all larger size class rearing systems, and the baskets in the ponds had the greatest growth rates. Smaller mussels had lower survival than the larger mussels, indicating that when deploying juvenile mussels into outdoor culture systems mussels size should be greater than 5.0 mm. Results of this project will inform future rearing yellow lampmussel in New England and more broadly add to the limited literature on probiotic use and secondary rearing designs in freshwater mussel culture. |
