Hawaii FEP - Western Pacific Fishery Council

The best information available is used to estimate the values of the reference points and todetermine the status of stocks in relation to the status determination criteria. The determinationsare based on the latest available stock and fishery assessments. Information collected includeslogbook data, creel survey data, vessel observer data (the observer program in the NWHI fisherywas recently reinitiated), and occasional fishery-independent surveys; however, at this time onlythe logbook data are used in stock assessments.The combination of control rules and reference points is illustrated in Figure 21. The primarycontrol rules that are applied to the stock complexes are shown in part (a). Note that the positionof the MSST is illustrative only; its value would depend on the best estimate of M at any giventime. The secondary control rule that will be applied to particular species as needed to providefor recovery from recruitment overfishing is shown in part (b).Moffitt et al. (2006) employed a dynamic production model applied to a time series of 2004bottomfish catch and effort data for the three management zones in the Hawaii Archipelago. Inthe Hoomalu Zone and Mau Zone, the analysis involved commercial fishery data (catch-per-day)from vessel logbooks and interview data (1988−2004). In the MHI, only the State of Hawaiicommercial catch data for the 1948−2004 period were used. A simplified three-parameterdynamic production model was fit simultaneously to the three time series of catch data bynonlinear regression. The model used is similar to the one described by Kobayashi (1996). Thisapproach reduces the number of fitted parameters by using outside information for someparameters and incorporating some shared parameters where applicable. It has been shown to bea useful approach for short time series involving geographically separate regions thought to havesimilar biological dynamics (Polovina 1989). The basic equation Moffitt et al.(2006) used for thedynamic production model is from Hilborn and Walters (1992) with a slight modification to thecatch formula that prevents catch from exceeding population size at high levels of exploitation(Dr. Richard B. Deriso, Inter-American Tropical Tuna Commission, pers. comm.). The equationcan be found in Moffitt et al. (2006). For each management zone, zonal MSY contribution(ZMC) reference points for the bottomfish fishery are calculated separately. Table 22 shows themetrics which resulted from this model and which indicated that MHI fishing mortality metricswere well above those of the other two zones and that excessive fishing pressure in the MHI wasthe major contributor to overfishing in the archipelago (Moffitt et al. 2006).Table 22: Archipelagic Reference Values for the Dynamic Production Model (2004 data)146