Meeting Abstract

61.6  Saturday, Jan. 5  Night and Day Comparisons of Predatory Reef Fish BASSETT, DK*; MONTGOMERY, J; University of Auckland, Auckland, New Zealand; University of Auckland, Auckland, New Zealand dbassett@mail.uri.edu

Nocturnal predatory fishes are an important component of marine ecosystems, yet few studies have investigated them in any detail. This study used a relatively new methodology, baited underwater video, as well as traditional underwater census surveys, in order to establish the diel activity patterns and relative abundance of temperate reef fish species along the northeast coast of New Zealand. Species predominantly active at night comprised 35% of total fish abundance. The dominant nocturnal predator found during underwater census surveys was the dwarf scorpionfish, Scorpaena papillosa, while the southern bastard cod, Pseudophycis barbata, was most frequently observed by baited underwater video. Other differences in the occurrence of fish species between these two sampling techniques were also found. These were attributed to the olfactory related and cryptic behaviour of these species. Nocturnal predatory fishes consumed mainly fish and mobile invertebrates, which represented fewer prey groups consumed than by the diurnal predatory species. These differences may be attributed to the feeding behaviour. Nocturnal predatory fish are likely to have large impacts on these prey groups within their local marine communities.