A STUDY OF THE HAWAIIAN DEEPSEA HANDLINE FISHERY WITH SPECIAL REFERENCE TO THE POPULATION DYNAMICS OF OPAKAPAKA, PRISTIPOMOIDES FILAMENTOSUS (PISCES: LUTJANIDAE).

摘要

A stock assessment of the Hawaiian deepsea handline fishery is presented, including both stock-production and year-class treatments of the fishery. This resource is composed principally of snappers (Lutjanidae), jacks (Carangidae), and a species of grouper (Serranidae) which are commercially harvested in offshore waters ranging in depth from 60-360 m.;A new method of estimating the age of tropical fish species is developed in which the density of daily increments is integrated across the breadth of otoliths. The increment density model is applied to the dominant species in the fishery (Pristipomoides filamentosus) and a growth curve is developed. Validation of increment periodicity is achieved by tetracycline injection of experimental fish, examination of shifts in field sampled size-frequency distributions, and comparisons with other lutjanid species.;A regression approach to an age-length key is elaborated and applied to stocks of P. filamentosus in Hawaii. This new and useful technique provides a transformation procedure for generating age-frequency distributions from length-frequency distributions and thus allowing mortality estimation by traditional catch curve methods. An analysis of yield/recruit is presented which is based on these results.;A brief study of the reproductive biology of P. filamentosus provides insight into the dynamics of growth in this species while ancillary investigations concerning gear selection and depth distribution show that bottomfish length-frequency samples are probably representative.;The stock-production analysis is cast into a multispecies setting and productivity is estimated with the total biomass Schaefer model. A multivariate statistical procedure is applied to commercial catch data and three recurrent species assemblages are identified. It is shown by aggregation theory that this procedure provides improved predictions of total catch.;The fishery currently appears to be near an optimal level of harvest at Penguin Bank. This is the principal fishing ground for these species in the archipelago, although further expansion of the fishery into the Northwestern Hawaiian Islands would seem possible.