The life history characteristics, growth and density of Mysis diluviana in Lake Pend Oreille, Idaho, USA

Application of management plans for lakes and fisheries, such as the addition of nutrients to increase lake productivity or the removal of non-natives, requires that we understand the biology and ecology of the biota present in those ecosystems. To understand the biology of a non-native freshwater shrimp, Mysis diluviana, and provide information for management of it in Lake Pend Oreille, a large (382km2) and deep (351m max depth) lake in northern Idaho, USA, we determined its life history characteristics, estimated growth rates, quantified seasonal density and calculated its production at two widely separated sites. M. diluviana required 2years to reach maturity; reproduction took place from September to October, and young were released between May and June. However, some gravid females and newly released young were observed year-round. Growth rates were higher in summer (0.037±0.004mm/day) compared to winter (0.023±0.003mm/day). Density varied from 56 to 2471 individuals/m2, while production ranged between 2.18 and 3.12g dry mass/m2/yr. These data can be used by managers of the Lake Pend Oreille ecosystem to optimize management strategies that increase kokanee production such as timing the potential application of nutrients, and/or the removal of mysids. Furthermore, we expand the knowledge of M. diluviana in large and deep lakes outside its native range.