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Analyses of Catch Data for Mahimahi (Coryphaena hippurus) and Wahoo (Acanthocybium solandri) from the Hawaii-Based Longline Fishery and Other Pacific Fisheries
The first objective will be to develop statistical models of catch rates for mahimahi and wahoo from the Pacific Islands Regional Observer Program catch data and then apply the model coefficients to the logbook data from the Hawaii-based longline fishery in order to identify outliers associated with reporting biases. This will increase the number and types of species with corrected, well-documented catch histories in the data archives of the Pacific Islands Fisheries Science Center.
The second objective is to determine whether, and if so, to what extent, intraspecific CPUEs for these species are correlated in various regions of the Pacific Ocean. This will entail comparisons of mahimahi and wahoo catch rates from several fisheries by use of appropriate correlation and time series techniques. Likely data sources, in addition to the Hawaii-based longline fishery, include troll data from the Hawaii Division of Aquatic Resources, offshore creel survey records from the Guam Division of Aquatic and Wildlife Resources, observer and longline logbook records from American Samoa, and offshore creel records from American Samoa.
The third objective will be to use the corrected CPUE trends from the Hawaii-based longline fishery to test predictions from ecosystem models (ECOSIM, ECOSPACE) for the North Pacific Ocean. These models suggest that fishes at lower trophic levels (e.g., mahimahi, wahoo) would exhibit compensatory responses to declines in higher trophic level predators (e.g. blue marlin, yellowfin tuna, blue shark). In this context, it is considered appropriate to use a one-sided alternative of significant increase relative to the null hypothesis of no significant temporal changes in CPUE.
The fourth objective will be to identify and estimate patterns in the sizes of these fishes. In the case of the Hawaii-based longline and commercial troll fisheries, individual weights of each fish sold at the United Fishing Agency public fish auction since January 1, 2000 will be available.
to Other PFRP Projects
This project is directly linked to four previous projects (listed below) that featured statistical analyses of catch data for several types of fishes. Results from these projects included evaluations of the accuracy of observer and commercial logbook data, identification and estimation of biases associated with self-reporting, and establishment of a research database with corrected estimates of catch totals and removals. This project will represent a meaningful enhancement to the earlier projects by providing thorough analyses of mid-sized predatory fishes and by identifying similarities or differences among fisheries and locales. By so doing, this should yield insight into spatiotemporal sources of variation in catch time series.
Histories, and Recent Catch Trends with Six Fish Taxa Taken as Incidental
Catch by the Hawaii-based Commercial Longline Fishery.” PIs: William
A. Walsh and Samuel G. Pooley. Project completed: FY 2002.
“Investigation of Shark Bycatch in the Hawaii-based Longline Fishery, and an Extension of Analyses of Catch Data from Widely Separated Areas in the Pacific Ocean.” PIs: William A. Walsh and Keith A. Bigelow. Funding date: September 2006. In progress
Funding received November 2008.
Dr. William A. Walsh
National Marine Fisheries Service
2570 Dole Street, Room 212
Honolulu, Hawaii 96822
Phone (808) 983-5346
FAX (808) 983-2902
This page updated September 27, 2010