Broad shifts in the resource use of a commercially harvested fish following the invasion of dreissenid mussels

Abstract

Dreissenid mussels, including the zebra (Dreissena polymorpha) and quagga (Dreissena rostiformus bugensis) mussel, are invasive species known for their capacity to act as ecosystem engineers. They have caused significant changes in the many freshwater systems they have invaded by increasing water clarity, reducing primary productivity, and altering zooplankton and benthic invertebrate assemblages. What is less clear is how their ecosystem engineering effects manifest up the food web to impact higher trophic levels, including fish. Here, we use a biological tracer (stable isotopes of carbon and nitrogen) to analyze long-term and broad-scale trends in the resource use of benthivorous lake whitefish (Coregonus clupeaformis) in the Laurentian Great Lakes, where dreissenid mussels have become established in each lake except Lake Superior. We measured stable isotope ratios from archived material (fish scale samples) collected over several decades by multiple agencies and from 14 locations around the Great Lakes. In the majority of locations, the δ C of lake whitefish increased following the establishment of dreissenid mussels. Trends in δ N were less clear, but significant breakpoints in the time series occurred within 5 yr of dreissenid establishment in several locations, followed by declines in δ N. In contrast, isotopic signatures in Lake Superior locations did not show these trends. Our results provide evidence that lake whitefish shifted toward greater reliance on nearshore benthic production, supporting the theory that fundamental energy pathways are changed when dreissenid mussels become established. Importantly, these effects were noted across multiple, large, and complex ecosystems spanning a broad geographic area. Our study underscores the potential for aquatic invasive species to alter key ecosystem services as demonstrated here through their impacts on energy pathways supporting a commercially harvested fish species.

Stable isotopes indicate that zebra mussels (Dreissena polymorpha) increase dependence of lake food webs on littoral energy sources

“…Second, the lakes are in close proximity, they are in the same catchment and have similar physical characteristics and trophic status. Third, several other studies have documented δ 13 C enrichment in lake food webs following zebra mussel infestation (Fera et al., ; Rennie et al., ; Turschak et al., ). Though previous studies have documented enriched δ 13 C values in lake food webs post zebra mussels, our study builds on this past work by using mixing models to document the actual amount reliance on littoral C increases as well as significant effects on trophic positions in lake food webs.…”

“…Two additional but somewhat inconsistent lower trophic level impacts are decreased zooplankton populations (Higgins & Vander Zanden, ) and increased growth of toxic cyanobacteria (Armenio et al., ; Fishman, Adlerstein, Vanderploeg, Fahnenstiel, & Scavia, ; Knoll et al., ). Relatively few studies have examined impacts of zebra mussels on fish communities, but the general response has been an increased reliance on littoral energy sources as evidenced by enriched δ 13 C in fish following colonisation (Fera, Rennie, & Dunlop, ; Rennie, Evans, & Young, ).…”

The failure of success: cyclic recurrences of a globally invasive pest

“…, Fera et al. ). This is supported by the interception data at ports of entry worldwide with annual OFF interceptions in at least tens of thousands.…”

Ecological change alters the evolutionary response to harvest in a freshwater fish

“…The growth and recruitment declines in lake whitefish represent an example of how the food web changes from dreissenids have manifested to impact a commercially harvested fish (Fera et al. , , Gobin et al. , ).…”

“…Lake whitefish stocks in the Great Lakes experienced broad‐scale shifts in diet, habitat usage, growth, and recruitment stemming from the invasion of dreissenid mussels (Fera et al. , , Gobin et al. , Rennie et al.…”