Resilience exemplified-drum fish spawning doesn't miss a beat in the eye of a hurricane

Abstract

Spawning locations, timing, and periodicity are important aspects of productivity and resilience in fish because they are directly related to reproductive success. Passive acoustic monitoring can be used to study these aspects of spawning for species that produce spawning associated vocalizations. Drumming sounds produced by spotted seatrout Cynoscion nebulosus during spawning have been extensively described and the sound pressure level (SPL) is correlated to the intensity of spawning. We monitored spawning in seatrout April-September 2017, which coincided with a category 4 hurricane and caused a major acute disturbance. Spawning sounds within the peak frequency bandwidth of seatrout chorusing (251-500 Hz) were observed on every day of the study with an average SPL of 121.8 (CI95 121.6-122.0) dBrms re: 1 μPa, which was significantly higher than the background noise level of 103.9 (CI95 103.8-104.0) dBrms re 1 μPa (w = 0.894, p<0.01). Spawning was also confirmed at two sites within the eye of the hurricane. The onset of spawning shifted 2.2 hours earlier (t = 13.91, df = 36, p < 0.01) for five days after the hurricane. These results illustrate that spotted seatrout are extremely resilient, which indicates a primary reason they are able to thrive in highly disturbed estuarine environments.