Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

Information Sources Used to Manage the Bristol Bay FisheryThe following is an overview of the assessment programs and data sources that are usedby AMBs to assess run strength and guide fishing effort. Despite the short duration ofthe fishery a suite of effective assessment tools has evolved that are small in cost relativeto the economic (and social) value of the fishery (Clark 2005; Appendix L). To theuninitiated, the list below may seem like a complicated array of assessment tools and therelative usefulness of each one is probably unclear. It is useful to keep in mind that thesingle most important information source used by AMBs is from the escapementmonitoring programs. AMBs manage fishing effort to distribute the escapement acrossthe season based on the historical run timing schedule. Typically, the lower and upperends of the escapement goal range are multiplied by the average run timing for a givensystem to provide the AMB a year-to-date benchmark to follow throughout the season(Figure 31).Escapement estimates are updated each day and plotted on this graph. Various runtiming scenarios are used to slide the target trajectory back and forth and assess theconsequences of the run being early or late. Depending on the observed escapement todate and the manager’s belief about the current year’s run timing, the fishery in eachdistrict is opened and closed. Fishing periods are usually at the beginning of a flood tide(the ebb tide is fished in the Nushagak District). Either the driftnet or set-net fishery maybe lagged to achieve the correct allocation between gear groups, but hitting theescapement goal is paramount. In addition, the manager tries to spread the escapementacross the entire season so as to promote genetic diversity and maintain the historic runtiming (e.g., Figure 32).All the additional information sources from other assessments influence the AMB’s“comfort level” with whether the fishery can be opened on a given tide or day whilemaximizing the chances that the annual escapement goal will be met for a given river. Ofcourse, choosing not to open comes with the risk of exceeding the escapement goal range.Combined with catch, the escapement monitoring projects provide a near immediatefeedback to the AMB’s view of the developing run. This real-time and iterative form ofmanagement to meet escapement goals makes only modest use of forecasted total run.Below we expound on the methods and reliability of the tools available to AMBs—inmore or less chronological order these are: (1) pre-season forecasts, (2) offshore testfishing at Port Moller, (3) district test fishing, (4) commercial fishery performance withcatch and age sampling, (5) inside test fishing, (6) aerial surveys, (7) escapementmonitoring.146