Acoustic competition of Serranids at a fish spawning aggregation

Abstract

Many fish species are known to produce stereotyped calls during spawning activities. It has been hypothesized that these calls play a vital role in coordination during this critical period. Competition for acoustic space can result in masking of calls and, as a result, may limit their function. Acoustic niche separation could be a solution to avoid acoustic competition for species that co-occur in a geographic area. The data from passive acoustic arrays deployed in Little Cayman, Cayman Islands, between 2015 and 2017 during the spawning of one of the largest aggregations of Nassau grouper (Epinephelus striatus) have been analyzed to explore acoustic niches in Serranids. At least three other vocal Serranid species are known to spawn at this location during the same time as Nassau grouper: red hind (E. guttatus), black grouper (Mycteroperca bonaci), and yellowfin grouper (M. venenosa). Call characteristics, such as the peak frequency, bandwidth, source level, and pulse period, were analyzed for all distinct calls from these species. In addition, temporal and spatial patterns of those calls were evaluated, allowing a detailed understanding of the communication space and acoustic competition potential for these cohabitating species.