Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $35,866 Total Non-Federal Funds: $71,742
Abstract: Quagga mussels (Dreissena bugensis) are a clear and imminent danger to the ecology and nutrient cycling in Lake Champlain. In the Great Lakes, the invasive quagga mussel has dramatically shifted system production from pelagic to benthic habitats with negative consequences on resource availability for pelagic-dependent trophic levels (Bunnell et al. 2014, Vanderploeg et al. 2010). The quagga mussel is also suspected to contribute to benthic algal blooms due to its ability to filter and excrete large amounts of phosphorus to its dissolved, bioavailable form (Conroy et al. 2005, Ozersky et al. 2013, 2015). Quagga mussels could have the same effects in Lake Champlain when they invade.Zebra mussels (D. polymorpha), close relatives to quagga mussels, have been in Lake Champlain since at least 1993; their impacts on fish communities and water quality have been limited (e.g., Smeltzer et al. 2012, Knight et al. 2018). However, invasion by quagga mussels may be a different story. Quagga mussels can easily colonize all depths of Lake Champlain (to the maximum lake depth of 122 m, Mills et al. 1996) and can easily outcompete zebra mussels (Ginn et al. 2018). Thus, quagga mussels will have a greater impact on the Lake Champlain system than the established zebra mussel (the latter is primarily limited to depths shallower than 25 m, Mills et al. 1999). Quagga mussels could drastically influence nutrient cycling and food web structure. If quagga mussels induce a shift from pelagic to benthic primary production in the lake, then pelagic-dependent forage fishes such as alewife (Alosa pseudoharengus) and2rainbow smelt (Osmerus mordax), and ultimately lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar), could be negatively impacted.The objective of our proposed project to VWRLSC is to map the current dreissenid densities throughout Lake Champlain and estimate their carbon storage to provide pre-quagga baseline estimates. Our proposed work will complement our current work to understand the carbon (i.e., energy) pathways of Lake Champlainâ€™s forage fish community - we are sampling the main components of the forage fish food web and analyzing them with stable isotopes, compound-specific isotope analysis of fatty acids, and gut analyses to trace the pathways of benthic and pelagic carbon. Results from both projects will be used to anticipate the effects of a quagga mussel invasion on the lakeâ€™s food web and water quality. The current food web structure and extent and density of zebra mussels in Lake Champlain are currently unknown. The estimates of dreissenid density and carbon storage from our proposed project to VWRLSC will help us determine the effects a quagga mussel invasion will have on how carbon flows from the base of the food web to the forage fish community. Additionally, our density estimates may be used in future modeling efforts to understand the impact dreissenid mussels will have on nutrient [re]cycling and, as a result, water quality. To properly prepare for an invasion, management agencies need to understand the current configuration of the Lake Champlain food web, and extent of carbon storage by dreissenids.