Crustacean zooplankton communities as indicators of game fish occurrence and abundance in Québec lakes

Abstract

Recreational inland fisheries play a vital role in the economy and culture of Canada. However, human activities and climate change are significant threats to lakes that sustain such fisheries, bolstering the need to maintain ecosystem quality while sustaining fisheries through approaches such as ecosystem-based management. Despite the importance of zooplankton communities for fish diet, very few freshwater management plans have integrated information from this lower trophic level. Here, we used a dataset including game fish abundance, crustacean zooplankton community composition and associated habitat variables in 94 north temperate lakes across the province of Quebec, Canada. Our study aimed to uncover whether zooplankton taxonomic and functional community properties were related to walleye, brook trout, and lake trout occurrence and abundance. Our analyses revealed that both taxonomic and functional zooplankton composition were significant predictors of focal fish species occurrence, albeit less so than environmental or fish community composition variables. When examining the importance of 30 different zooplankton community indices for target fish species abundance, structural equation modeling revealed that zooplankton was more important for walleye than for the two other fish species. Overall, this research improves our understanding of zooplankton-fish interactions and how these shape north temperate lake communities, with a perspective of improving fisheries conservation and management.