MONITORING FISH SPAWNING LOCATIONS AND MARINE MAMMAL SOUNDS WITH PASSIVE ACOUSTIC RECORDER ON A WAVE GLIDER

"Remote observations of marine animal behavior have one distinct advantage over direct observations: the observer is not present to disturb the animals. There are no vessel noises , no diver's bubbles , no people present that could alter the behavior of the animals being observed. Because fishes and marine mammals are known sound producers , these animals' location while producing sounds during a mobile survey can be recorded , and their species identity determined; in some cases , their behavior can be associated with specific sounds. We used Blackbeard the Acoustic Wave Glider (AWG) to conduct affordable , mobile , long-term passive acoustic monitoring of marine animals and the coastal ocean acoustic environment off North Carolina. (Luczkovich et al. , in press). Passive acoustic methods from fixed recording platforms have been used previously to document spawning locations of weakfish , Cynoscion regalis , and other fishes in the drum family Sciaenidae in estuarine environments (Luczkovich et al. 2008). Others have demonstrated that sciaenid fishes make spawning ""drumming€ calls outside the inlets on the continental shelf (Conaughton and Taylor , 1995; Holt , 2008). However , ""chattering€ sounds that were reported offshore by Conaughton and Taylor (1995) were actually later shown to be due to striped cusk-eels , Ophidion marginatum. Here we report that choruses and individual calls of many fish (weakfish , striped cusk-eels , red drum , Sciaenops ocellatus , spotted sea trout , Cynoscion nebulosus , sea robins Prionotus sp. , oyster toadfish Opsanus tau and an unknown grouper Epinephelus sp.) were recorded during wave glider transects running along the 20 and 30 m depth isobaths along the continental shelf of North Carolina coast. Marine mammal sounds (humpback whales Megaptera novaeangliae and bottlenose dolphins Tursiops truncatus) were also recorded during these excursions. The estuarine-dependent weakfish spotted seatrout , and red drum fishes (Sciaenidae) were more common in shallow areas (~20 m) near inlets and by artificial reefs , whereas the grouper calls were recorded in deeper water (~30 m) on live bottom reefs. These fishes' sounds are likely to be associated with spawning , suggesting spatial separation of their spawning areas , and extending the known spawning habitats for these species beyond estuaries. The AWG can be used to map critical spawning habitat in offshore areas where anthropogenic vessel noises occur , and where energy development has been planned.