Experimental measurements of escape performance in fishes have typically been conducted in still water; however, many fishes inhabit environments with flow that could impact escape behavior. We examined the influences of flow and predator attack direction on the escape behavior of fish, using juveniles of the amphidromous Hawaiian goby Sicyopterus stimpsoni. In nature, these fish must escape ambush predation while moving through streams with high-velocity flow. We measured the escape performance of juvenile gobies while exposing them to a range of water velocities encountered in natural streams and stimulating fish from three different directions. Frequency of response across treatments indicated strong effects of flow conditions and attack direction. Juvenile S. stimpsoni had uniformly high response rates for attacks from a caudal direction (opposite flow); however, response rates for attacks from a cranial direction (matching flow) decreased dramatically as flow speed increased. Mechanical stimuli produced by predators attacking in the same direction as flow might be masked by the flow environment, impairing the ability of prey to detect attacks. Thus, the likelihood of successful escape performance in fishes can depend critically on environmental context.
The authors declare no competing or financial interests.
K.M.D., H.L.S. and R.W.B. designed the study and collected the data; K.M.D. and J.A.W. analyzed the data; all authors contributed to manuscript drafts and revisions.
Support was provided by Sigma Xi (K.M.D.), Clemson Creative Inquiry grant no. 479 (R.W.B.) and St Cloud State University SCSU-211228 Short-Term Faculty Improvement Grant (H.L.S.).
Fish specimens from this study are curated in the Campbell Museum of Natural History at Clemson University. Data table and R sweave code for this project can be found at the following link: https://github.com/middleprofessor/Goby.
Supplementary information available online at http://jeb.biologists.org/lookup/doi/10.1242/jeb.137554.supplemental
- Received January 14, 2016.
- Accepted July 22, 2016.
- © 2016. Published by The Company of Biologists Ltd