Temporal trends in Mysis relicta abundance, production, and life-history characteristics in southeastern Lake Michigan

Recent changes in primary production and phytoplankton in the offshore region of southeastern Lake Michigan

“…Second, and maybe more important, is the possibility that phosphorus recycling and utilization in Lake Michigan have been altered due to recent foodweb changes. Not only have large populations of dreissenid mussels become established with documented effects on phosphorus recycling and transport (Hecky et al, 2004), but significant changes in cyclopoid copepods, Daphnia spp., Diporeia and possibly Mysis relicta populations have also been noted in Lake Michigan since 2000 (Nalepa et al, 2009;Pothoven et al, 2010;S. Pothoven, unpubl.…”

Lake Michigan lower food web: Long-term observations and Dreissena impact

“…Bythotrephes consumption needs varied seasonally with an early peak in August followed by another peak in October and no trends in annual consumption were noted for a 10-year period (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003). This suggests that the declines in crustacean zooplankton abundance in the last decade (Kerfoot et al, 2010;Pothoven et al, 2010) were not caused by changes in Bythotrephes predation.…”

“…Given the precipitous decline of the benthic amphipod Diporeia, (Nalepa et al, 2009) there are questions about the health of Mysis populations because both of these organisms are heavily fed upon by forage fish. In the first paper, Pothoven et al (2010Pothoven et al ( ) noted that 2007Pothoven et al ( -2008 Mysis abundance was lower than in 1995-2002, declining 70% at the 110-m offshore site. This could be related to a reduction in food availability due to the recent disappearance of the spring diatom bloom and/or to an increase in fish predation despite lower fish abundance.…”

Seasonal zooplankton dynamics in Lake Michigan: Disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

“…At the same time, macroinvertebrates favored as prey by planktivorous fishes-Diporeia spp. and Mysis-have both decreased with the former species nearly disappearing (Nalepa et al, 2009;Pothoven et al, 2010). Declines in these key macroinvertebrates may ultimately lead to declines in prey fish biomass.…”

“…Mysis would likely compete with Limnocalanus for prey since they both prey on zooplankton (Table 1; Bowers and Vanderploeg, 1982) and it is conceivable that Mysis could prey on L. sicilis. Pothoven et al (2010) hypothesized that the decrease in Mysis was caused by food limitation of the early instars associated with the decimation of the spring diatom bloom.…”