Behavioral Changes in a Coastal Marine Fish Lead to Increased Predation Risk Following Oil Exposure

Abstract

Fishes exposed to crude oil have shown reduced sociability and poor habitat selection, which corresponded with increased predation risk. However, the contribution of oil-induced cardiorespiratory impairments to these findings is uncertain. This study explores the effect of oil exposure on predation risk in a model fish species, Sciaenops ocellatus, across a suite of physiological and behavioral end points to elucidate the mechanisms through which any observed effects are manifested. Using mesocosms to assess group predator avoidance, oil exposure to 36.3 μg l–1 ΣPAH reduced the time to 50% mortality from a mean time of 80.0 (74.1–86.0 95% confidence interval [CI]) min to 39.2 (35.6–42.8 95% CI) min. The influence of oil impaired cardiorespiratory and behavioral pathways on predation risk was assessed based on respiratory performance, swim performance, sociability, and routine activity. Swim trials demonstrated that cardiorespiratory and swim performance were unaffected by exposures to 26.6 or 100.8 μg l–1 ΣPAH. Interestingly, behavioral tests revealed that exposure to 26.6 μg l–1 ΣPAH increased distance moved, speed, acceleration, and burst activity. These data indicate that behavioral impairment is more sensitive than cardiorespiratory injury and may be a more important driver of downstream ecological risk following oil exposure in marine species.

Brief Oil Exposure Reduces Fitness in Wild Gulf of Mexico Mahi-Mahi (Coryphaena hippurus)

“…Since the DWH spill occurred in 2010, scientists and policy makers have pursued the question of what impact the release of more than 3 million barrels of crude oil had on individuals and populations of marine organisms. ,, Laboratory studies have categorized the physiological, behavioral, , and cognitive damage , that sublethal oil exposure can cause, but until the present study, the fine-scale behavior and reproductive activity of oil-exposed fish had not been tracked in the wild over long periods. By combining tagging and transcriptomic techniques from noninvasive fin clips, we were able to use a new application of tools to link changes in gene expression to the behavior, survival, and reproductive success of wild fish in their natural habitat.…”

“…In fact, for fish that did not retain tags past 8 days in the wild, either due to predation or unknown causes, time to 50% survival was over 5 days for control fish, while for oil-exposed fish, it was 2 days. In the laboratory, oil-exposed marine fishes suffer elevated predation rates, 43,44 although previously, it was not clear whether these impacts would translate to the natural environment. For mahi-mahi that reached at least 9 days at liberty, survival likelihood was not different between the groups (Kaplan−Meier survival curve, p > 0.05).…”

“…Similarly, behavioral and physiological impacts of oil exposure may persist 8 days or longer in the laboratory. 54,55 Transcriptomic 56 and behavioral 43 data from oil-exposed red drum (Sciaenops ocellatus) have also highlighted hyperactivity, and this behavior is hypothesized to be caused by damage to the central nervous and sensory system receptors. 7 Juvenile oilexposed mahi-mahi show different behavioral responses to olfactory cues than control fish, a change underlain by damage to central nervous system processing.…”