PCBs and other toxicants in Mysis relicta

Abstract

This research considers the role of Mysis relicta in the recycling of toxic organics in the Lake Michigan ecosystem. Mysids were collected at a station 20 km offshore of Grand Haven, Michigan in spring, summer, and autumn and then size-sorted. In October 1980 and May 1981, plankton samples were collected in two size categories: >78 um and >156 m. Mysid fecal pellets and Pontoporeia hoyi were collected in May 1981 while a fourhorn sculpin (Myoxocephalus quadicornis) was collected in October 1980. Concentrated extracts of all samples were analyzed for chlorinated hydrocarbons using electron capture gas chromatography. Toxic organics detected were, in order of concentration: PCB, DDE, dieldrin, y/-chlordane, and HCB. DDT, DDD, and a-chlordane were detected less frequently. PCB concentrations in mysids were similar to those observed in their plankton diet and there was no evidence of increased bioaccumulation with increased mysid age. Dieldrin and DDE generally occurred in higher concentrations in older than in younger mysids. Dieldrin concentrations were lower in the plankton than in mysids. Certain toxicants (PCBs, DDD, dieldrin, and y-chlordane) occurred in higher concentrations in Pontoporeia hoyi than in mysids. Concentrations in the sculpin generally were intermediate to those in amphipods and mysids. Our study suggests that mysids have a significant role in the recycling of toxic organics and that the characteristic pathways vary with the contaminant.

Forecasting the ecological impacts of the Hemimysis anomala invasion in North America: Lessons from other freshwater mysid introductions

“…Mysids recycle contaminants by grazing on floating detritus in the water column, consuming contaminated sediments or by preying on benthic invertebrates, before themselves being consumed by fish (Evans et al, 1982;Van Duyn-Henderson and Lasenby, 1986). Their vertical migrations result in the transport of heavy metals between benthic and open-water food webs (Northcote, 1991).…”

Measuring life‐history omnivory in the opossum shrimp, Mysis relicta, with stable nitrogen isotopes

“…The opossum shrimp, Mysis relicta, has received considerable attention in recent studies that examine the effects of trophic structure on contaminant bioaccumulation in aquatic food chains (Evans et al 1982;Rasmussen et al 1990;Cabana and Rasmussen 1994;Bentzen et al 1996;Vander Zanden and Rasmussen 1996). As a predator on zooplankton, M. relicta may represent up to one complete additional trophic level and thereby contribute significantly to higher contaminant loads in top predators such as lake trout.…”

“…See Table 1 mysids. Fishes that are positively size selective on adult mysids (Janssen and Brandt 1980) may be expected to accumulate much higher loads of contaminants (Evans et al 1982) in comparison to fishes foraging on either juvenile mysids or the bulk zooplankton. Consequently, careful consideration should be taken in assigning trophic positions to consumers in food chains where mysids are an important link.…”

The effects of land use and cultural development on the Lake Ontario ecosystem since 1750

“…However, none of these biotic responses have yet been shown to be unique to specific contaminants. Evans et al (1982) reported that certain toxicants (PCBs, DDD, dieldrin and y-chlordane) were higher in the benthic feeding amphipod Pontoporeia hoyi than in the larger predatory mysid Mysis relicta, but concentrations of DDE were greater in the larger mysids than in their plankton diet. The authors presented data that indicate mysids appear to be more efficient at excreting PCBs and some other contaminants than Pontoporeia.…”