Early mortality and freshwater forage fish recruitment: nonnative alewife and native rainbow smelt interactions in Lake Champlain

• Published in: Canadian journal of fisheries and aquatic sciences 2019-05, Vol.76 (5), p.806-814
• Main Authors: Simonin, Paul W, Rudstam, Lars G, Sullivan, Patrick J, Parrish, Donna L, Pientka, Bernard
• Format: Article
• Language: English
• Subjects: Abundance; Adults; Age composition; Age groups; Alewife; Alosa pseudoharengus; Analysis; Aquatic sciences; Biological age; Climate change; Climate effects; Coexistence; Computer simulation; Distribution patterns; Environmental aspects; Fish; Fishes; Food chains; Forage fishes; Forage species; Freshwater; Freshwater fish; Geographical distribution; Global temperature changes; Growing season; Introduced species; Invasive species; Juveniles; Lakes; Light; Light penetration; Modelling; Mortality; Natural mortality; Nonnative species; Osmerus mordax; Population biology; Population density; Population structure; Rainbows; Recruitment; Recruitment (fisheries); Simulation; Smelts; Studies; Water temperature
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/cjfas-2017-0571

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt (Osmerus mordax) and nonnative alewife (Alosa pseudoharengus) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-the-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant, and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment.