Using passive acoustics to localize vocalizing oyster toadfish (Opsanus tau)

Identifying where fish inhabit is a fundamentally important topic in ecology and acoustic tools can help management to prioritize acoustically sensitive times and areas. In this study, passive acoustic monitoring is presented as a viable tool for monitoring the positions of vocalizing fish species, like the oyster toadfish. Time of arrival differences (TOADs) of sound recordings on a four-hydrophone array were used to pinpoint the location of male oyster toadfish, Opsanus tau, a sedentary fish that produces boatwhistle vocalizations to attract females. Coupling the TOAD method with cross correlation of the different boatwhistles, individual toadfish were mapped during three-hour periods at dawn, midday, dusk, and midnight to examine the relationship between temporal and spatial trends. Seven individual males were identified within 24.2 m of the hydrophone array and up to 18.2 m of the other individuals. The advantages and disadvantages of using the TOAD method to localize individual fish will be discussed. Additionally, preliminary data on how individual toadfish respond to the anthropogenic sound of passing motorized vessels as well as conspecific boatwhistles will be introduced.