A potential trophic role for Trout-perch (Percopsis omiscomaycus) in coupling nearshore and offshore lake food webs

Abstract

Trout-perch (Percopsis omiscomaycus) is an abundant, small-bodied, benthic fish species often found in deeper regions of large lake ecosystems. Historical evidence suggests that Trout-perch may participate in nearshore lake food webs by migrating from deep to shallow areas at night. However, little is known about Trout-perch ecology or their potential role in nearshore food webs. We used Trout-perch abundance estimates, diet analysis, and benthic invertebrate community surveys to (1) assess Trout-perch trophic ecology in Lake Champlain, USA/CAN, and (2) determine whether deepwater prey resources existed at sufficient densities to support Trout-perch populations or whether supplemental prey resources were required. Trout-perch showed variability in size and biomass across lake regions, but diet patterns were largely consistent across the lake, with > 50% of diets consisting of emergent insect larvae and oligochaetes. Results suggest that migrations into nearshore habitats may be required to sustain Lake Champlain’s Trout-perch populations, and therefore, Trout-perch could function as conduits of allochthonous energy across distinct lake habitat boundaries. This study is one of only a few that have examined the trophic ecology of Trout-perch in deep lakes and fundamentally improves our understanding of energy flow and coupling between distinct lake food web compartments in large lakes.