Acoustic characterization of sound production by the Pot-Bellied Seahorse (Hippocampus abdominalis)

Abstract

Sound production is a critical component of predator-prey interactions. In order to understand why seahorses produce sound in various instances (i.e., courtship, feeding, and stress), we must first quantify the acoustic parameters of the signal. Seahorses produce sound with a stridulation of the supraoccipital bone and the coronet by moving their head upwards in a motion that is referred to as a “snick.” The acoustic signal that accompanies this head movement is called a “click.” We set out to analyze the sound parameters of the largest seahorse species, Hippocampus abdominalis, housed at the Newport Aquarium. Adult and juveniles were tested each individually and allowed one hour to acclimate to an isolated tank. Feeding on brine shrimp (Genus: Artemia) was observed with video and audio recordings that were collected for approximately 12 minutes. SpectraPLUS was used to evaluate the frequency, intensity, and number of clicks present in the audio recordings. The video footage allowed for analysis of the presence of the snick. By characterizing the sound production in this species of seahorse we are able to begin to answer the question of the purpose for the click and snick behavior.