Graduate Exit Seminar - Victoria Drumm

Plan to join Victoria Drumm's graduate exit seminar on December 18, 2024, at 12:00 pm via Zoom. Victoria will present, "Impacts of intermittent light pollution on Bluegill Sunfish (Lepomis macrochirus) foraging and antipredator behaviors"

Abstract: Artificial light at night (ALAN) is an increasingly prevalent anthropogenic stressor capable of disrupting normal patterns of behavior in a diversity of taxa, including fishes. While many knowledge gaps still limit our understanding of the impacts of continuous ALAN exposure on fishes, the effects of intermittent ALAN, such as the pulses of light introduced by passing road vehicles, are particularly understudied. Bluegill Sunfish (Lepomis macrochirus) forage at reduced rates under intermittent relative to continuous ALAN, but the mechanism driving this effect is unknown. To explore the hypothesis that this effect is driven by increased perceived risk of predation under intermittent ALAN, I assessed Bluegill foraging and antipredator behaviors under intermittent and continuous ALAN of an intensity emitted by passing vehicles onto roadside streams. I conducted three behavioral assays in a controlled mesocosm setting, examining 1) foraging, 2) flight initiation distance, and 3) shoaling. In the foraging and shoaling assays, light treatments were presented in combination with the presence or absence of a natural predator of Bluegill, Largemouth Bass (Micropterus salmoides), to determine whether intermittent ALAN’s impacts on Bluegill behavior interact with predation risk level. Exposure to intermittent ALAN appeared to reduce how often Bluegill struck at prey, increase the efficiency of their foraging, and lead to increased rates of shoaling behavior, but did not alter their flight initiation distances or show any interactive effects with bass presence. Bluegill also displayed increased latency to begin foraging under both intermittent and continuous ALAN, and foraged disproportionately less efficiently when bass were present under continuous ALAN, compared to intermittent ALAN and darkness. My results do not offer consistent evidence of intermittent ALAN increasing perceived predation risk in Bluegill, but do suggest that patterns of intermittent ALAN produced by road vehicles may be capable of suppressing foraging activity and increasing shoaling rates in this widely distributed and economically important sportfish species.    

Advisor: Dr. Christopher Tonra