Meeting Abstract

 

58-6  Saturday, Jan. 5 11:30 – 11:45  The Effect of Light Stimuli on Dark-Adapted Visual Sensitivity in Invasive Silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) Carp ROGERS, LS*; VETTER, BJ; MENSINGER, AF; University of Minnesota Duluth; University of Washington; University of Minnesota Duluth roger710@d.umn.edu

Since the accidental introduction of silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp into the southern part of the United States in the 1970’s, these fishes have migrated northwards through the Mississippi River Drainage and now threaten the Laurentian Great Lakes. To control the further expansion of these invasive carp, fisheries managers have been working to develop effective non-physical barriers, which include underwater strobe lights used either alone or paired with sound and/or bubbles. To optimize the use of potential optical deterrents, it is necessary to understand the visual sensitivity of the fishes and the impact these non-physical barriers have on the visual system. Using the electroretinogram (ERG) technique, dark-adapted silver and bighead carp were found to possess broad visual sensitivity between 470 nm to 620 nm, with peak spectral sensitivity at 540 nm and 560 nm, respectively. To assess the impact of strobe light on vision, dark-adapted silver, bighead, and common carp (Cyprinus carpio), were exposed to three different 5-second trains (100, 200, or 500 ms on/off flashes) of white light (760 lumen) and the recovery of visual sensitivity was determined by measuring the b-wave amplitude of the ERG. For all species, the longest recoveries were observed in response to 500 ms flash trains. Recovery to > 50% for silver and bighead carp took up to 360 s, while common carp took up to 240 s. Recovery time to ≥ 90% for silver carp took 702.0 s ± 89.8 (mean ± 1 SE), bighead carp 648.0 s ± 116.0, and common carp 480 s ± 180.0. The results suggest that exposure to strobe light can temporarily depress visual sensitivity, which may render optical barriers less effective.