Meeting Abstract

33.5  Sunday, Jan. 5 09:00  Visual Sensitivities of Deep Water Fishes in Lake Superior HARRINGTON, K.A.*; HRABIK, T.R.; ALLEN, A.F.; University of Minnesota; University of Minnesota ; University of Minnesota harr1582@umn.edu

The mid and deep water trophic interactions have been well established in Lake Superior. The primary predator, siscowet, a fatty morphotype of lake trout (Salvelinus namaycush) will feed primarily on deepwater sculpin (Myoxocephalus thompsonii) on the lake bottom during the day. However, they will also consume kiyi (Coregonus kiyi) and follow them on their diel vertical migration (DVM) to obtain mysis (Mysis duluviana). Thus, the siscowet and kiyi remain at depth during the day and only migrate to shallow waters at night which maintains them in light limited environments. Therefore, it is unclear what is the main sensory system (vision or lateral line) mediating predator prey interactions. To determine the role of the visual system, spectral sensitivity curves were generated using electroretinography from 400-700 nm. All three fishes experience peak sensitivities between 500 and 550 nm with siscowet and kiyi displaying similar sensitivities consistent with their DVM pattern. However, the deepwater sculpin’s visual system demonstrates a higher sensitivity between 475 and 550 nm relative to the other wavelengths in comparison to the other fishes. This suggests the deepwater sculpin has a unique sensitivity specialized for wavelengths available at depth. Despite a relatively new (< 15,000 years) colonization of deep lake waters, the fishes’ visual systems have evolved to maximize prevailing light in their environment. Concurrent behavioral studies are determining whether the light intensities and visual sensitivities are sufficient to mediate predator prey interactions. Funded by Sea grant 1205A13881.