Mysis diluviana in the Great Lakes: historic drivers of abundance and production, and current status in Lake Ontario

Abstract

Mysis diluviana are small, shrimp-like crustaceans native to the Laurentian Great Lakes, where they are important as planktivores and as prey for fish. Therefore, our understanding of offshore Great Lakes food webs requires an understanding of M. diluviana population dynamics in these systems. In this thesis, I review the factors observed to influence the abundance, life history, and production of M. diluviana in the Great Lakes, and report recent status (2013) in Lake Ontario, including the first production estimate since 1995. In Lake Ontario in 2013, M. diluviana abundance, biomass, and production were less than 50% of values in the 1990s, but age-0 growth rate and age-1 fecundity were higher. These results suggest food limitation was not the cause of the observed declines in abundance in the late 1990s.