Effects of the Establishment of Mysis relicta on the Macrozooplankton of a Large Lake

Abstract

The effects of the introduction of opossum shrimp Mysis relicta on the macrozooplankton of Pend Oreille Lake, Idaho were examined from recent and historic zooplankton data. Establishment of M. relicta was associated with a temporal displacement in the seasonal occurrence of Daphnia and Bosmina species and a change in the species composition of Daphnia present. The amount of interaction between cladocerans and mysids appeared to be related to the vertical distribution of each. The cladocerans appeared and increased in abundance as the mysids became seasonally isolated from near-surface strata by increasing thermal stratification and transparency.

Changes in species composition of cladoceran community in Lake Kasumigaura during 1986-1989: Occurrence of Daphnia galeata and its effect on algal biomass.

“…Previous studies on the zooplankton community in Lake Kasumigaura (YASUNO et al, 1977; MOKISHITA and YASUNO, 1979;YASUNO et al, 1981;HANAZATO and YASUNO, 1985a, 1987a, 1988 RICoARDS et al, 1975;GOLDMAN et al, 1979;RIEMAN and FALTER, 1981;LANGELAND, 1988). In Lake Stugusjoen (Norway), Cladocera was scarce when the biomass of mysids (Mysis relicta) was reportedly high (50-300 mg dry wtm-z) (LANGELAND, 1988).…”

Effects of Underwater Sound Simulating the Intermediate Scale Measurement System on Fish and Zooplankton of Lake Pend Oreille, Idaho

“…(Bowler et al 1980). Additionally, the introduction of the opossum shrimp Mysis re/icta in 1966 0 and subsequent changes in the macrozooplankton community may have been detrimental to the kokanee population (Rieman and Falter 1981). Low kokanee abundance combined with many "unknown effects" of historic changes in Lake Pend…”

“…Lake Pend Oreille has been characterized as a 'morphometrically oligotrophic' 0 lake because of its extreme depth (mean= 165 m), deep mixing of plankton-containing 0 (Rieman and Falter 1981). These characteristics combine to suppress primary productivity, though phosphorus loading 0 into the lake is moderately high at 1.37 g P/m 2 (Watson et al 1987;Beckwith 1989).…”

Kokanee Stock Status and Contribution of Cabinet Gorge Hatchery, Lake Pend Oreille, Idaho, 1991 Annual Progress Report.

“…In addition to providing an important fishery, kokanee.are the primary forage for trophy Gerrard rainbow trout and bull trout Salvelinus confluentus in Lake Pend Oreille. (Rieman and Falter 1981). The Idaho Department of Fish and Game (IDFG) introduced them to enhance the kokanee forage base.…”

“…Prior to 1985, hatcheries could provide only 6 to 8 million kokanee fry annually for Lake Pend Oreille. Research indicated that releases of up to 20 million fry annually may be necessary to restore the fishery to historic levels (Rieman 1981).…”