ABSTRACT
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Catch and Effort Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Tidal Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Wind and SST Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Current Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Coral Sea Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 Interannual Variability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 Coral Sea Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Seasonal Coral Sea Circulation Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Daily Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Tides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Winds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Water Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Information on the distribution and abundance of fish resources is essential for their wise utilisation and management. Knowledge of their life history strategies enables fishers to target their activities and managers to consider, among other things, regional and seasonal closures as tools for sustainable management. Environmental factors influencing the distribution and abundance and, subsequently, the availability of pelagic fishes are sometimes overlooked or little understood by managers (Hoey
et al., 1995) but well recognised by researchers. For example, water temperature plays a significant role in the movements of highly migratory species such as tunas and billfishes (Chapman, 1972; deSylva, 1990). Catches of striped marlin, Tetrapterus audax, off southern California, are made when water temperature is between 16.1 and 22.8°C. Catch rates peak at a water temperature of 19.9 0.25°C and increase somewhat exponentially with temperature (Squire, 1985). A unique physiological adaptation to billfishes, the thermogenic tissue derived from eye muscle tissue (Block, 1986), enables these fishes to maintain warmer temperatures in the cranial and optic cavities thereby enabling them to search for food in deeper and cooler waters (Davie, 1990).
