Meeting Abstract

23.7  Saturday, Jan. 4 14:45  The role of vertebral morphology in a fish eat fish world ACKERLY, KL*; WARD, AB; McGill University; Adelphi University kerri.ackerly@mail.mcgill.ca

Many selective factors work together to determine the optimal body morphology to maximize swimming performance in fishes. The vertebral column is one of the most important morphological elements in determining maximum swimming performance. Variation in vertebral morphology has been shown to significantly impact escape swimming performance, leaving individuals more susceptible to predation. Our previous work in zebrafish (Danio rerio) has shown that individuals with fewer vertebrae and a higher vertebral ratio have decreased escape response performance. This performance variation is a result of a decreased number of intervertebral joints present within individuals with a lower number of vertebrae, which decreases the range of axial skeleton flexion. The evaluation of the effects of morphology on performance and the subsequent effect of this performance on fitness is crucial for determining the adaptive nature of these various morphologies. We are currently working to make the connection between the ecological importance of vertebral variation and identify the selective factors behind it. To do this, we are exposing populations of zebrafish with various vertebral morphologies to native predators, needlenose garfish (Xenentodon cancila), to identify selective predation for certain vertebral morphologies. Comparison of vertebral morphology between the zebrafish that survived the trials and those consumed by the predators revealed temperature specific selective predation for individuals of different vertebral morphologies. These findings highlight the multifaceted nature of predator-prey interactions and the predator-specific nature of selection, while also giving insight into possible selective pressures that these and other ectothermic aquatic vertebrates may face as new threats arise in a rapidly changing climate.