Is sediment or pseudofaeces toxicity responsible for the decline of the amphipod Diporeia hoyi in Lakes Erie and Ontario?

Abstract

The deepwater amphipod Diporeia hoyi has disappeared from Lake Erie and much of Lake Ontario at depths <80 m. This amphipod had supplied 20 percent of the fisheries energy budget in the Great Lakes. The exotic mussel Dreissena bugensis now forms most of the benthic biomass above 60 m depth, but Diporeia is absent over large areas where Dreissena are rare. The filamentous bacterium Thioploca ingrica is now common at many sites between 30 and 40 m where Diporeia has disappeared. Fisheries and Oceans, Canada, investigated the causes of the decline by examining the sediment chemistry, bacterial production and conducted sediment bioassays using Diporeia, Hyalella and Microtox R . Microtox R showed no evidence of toxicity in sediments now devoid of Diporeia. Amphipod survival and growth was greatest in sediment that rapidly lost its Diporeia population in 1993. Presence of Thioploca had no effect on Diporeia survival. Hyalella was more sensitive than Diporeia to test sediments and to filtered water from mussel cultures. Sediment from sites with dense Dreissena populations had lower Diporeia survival. A diet of mussel pseudofaeces caused significantly lower survival in both Hyalella and Diporeia. The exact mechanism causing lower survival is currently unknown and may be related to a nutritional problem or associated waste metabolites.

Gathering at the top? Environmental controls of microplastic uptake and biomagnification in freshwater food webs

“…Pseudofaeces of Dreissena and other common freshwater bivalves (Corbicula sp, and Unionidae mussels) are rejected organic and inorganic particles covered by mucus in the mantle cavity of the mussel, and expelled outside (Dermott, 2005). It is well established that many benthic animals prefer to feed on Dreissena pseudofaeces because of their high nutritional values (Stewart, 1998).…”

Field assessment of condition indices (nucleic acid and protein) in Mysis diluviana

“…Dreissenid mussels now also help to move phytoplankton production to the fish community in Lakes Ontario, Erie, Michigan and Huron, where they are replacing Diporeia spp. (Dermott et al 2005, McNickle et al 2006, Nalepa et al 2006. In response, the distributions and diets of fish such as alewife and lake whitefish Coregonus clupeaformis have been shifting, and diets have been broadening to include alternative prey such as dreissenids and mysids (O'Gorman et al 2000, Pothoven et al 2001, Hoyle et al 2003, Hondorp et al 2005.…”

“…The lake was changing rapidly with the arrival and expansion of several aquatic invasive species: dreissenid mussels Dreissena polymorpha and D. bugensis, predatory cladocerans Bythotrephes longimanus and Cercopagis pengoi, and the round goby Neogobius melanostomus (Dermott & Geminiuc 2003, Johannsson 2003, Dermott et al 2005, Warner et al 2006, Walsh et al 2007, Watkins et al 2007), all of which could potentially impact mysid populations. In the Laurentian Great Lakes (Superior, Michigan, Huron, Ontario, but excluding Erie), M. diluviana and Diporeia spp.…”

Stable isotope patterns of benthic organisms from the Great Lakes region indicate variable dietary overlap ofDiporeiaspp. and dreissenid mussels

“…In laboratory experiments using Diporeia from several populations, there were few negative effects directly related to feeding on pseudofeces (Dermott et al 2005b). Pseudofeces have also been shown to lower the ␦ 13 C values of amphipods feeding on fine benthic organic matter in the Ohio River while improving the quality of their food (Greenwood et al 2001).…”

“…Dreissenids are confined to shallow regions in the western portion of Lake Superior, and Diporeia populations in this lake have remained stable thus far (Nalepa et al 2006b; Barbiero et al 2011). Mechanism(s) that lead to declines of Diporeia are unclear but may include toxins associated with dreissenid pseudofeces or competition with dreissenids for food (Dermott et al 2005b;Nalepa et al 2006a). This last hypothesis has received much attention but has been difficult to prove.…”