Stock assessment and fishery management of the South Atlantic albacore (Thunnus alalunga)
Date of Award
Doctor of Philosophy (Ph.D.)
First Committee Member
Nelson M. Ehrhardt, Committee Chair
The albacore, Thunnus alalunga is the only species marketable as "white meat tuna" and is invaluable to the tuna canning industry. The International Commission for the Conservation of Atlantic Tunas has expressed great concern about the ability of the Atlantic albacore stocks to sustain the current high catch rates. The South Atlantic albacore stock is also of particular concern to Taiwan because Taiwanese longline vessels presently account for over 70 percent of the total catch, and no adequate measures have ever been proposed for its management. The purpose of this study was to provide a basis for generating the scientific advice necessary to develop management strategies for the optimal utilization and conservation of the South Atlantic albacore. To achieve this goal, the life history of albacore and the fisheries that exploit it were reviewed. The information gleaned from the reviews was synthesized using three different modelling approaches: production, yield per recruit, and time series models. The results indicate that the South Atlantic albacore stock is, at best, fully-utilized or more likely slightly over-utilized relative to the maximum sustainable yield. Two alternative management strategies are recommended to keep the stock near the biomass producing the maximum sustainable yield for the next decade: (1) The total catch of albacore in the South Atlantic should be restricted to not more than 21,000 mt; (2) The Taiwanese fishing mortality should be reduced by 18% or by 20% in tandem with a 5% increasing in the South African fishing mortality relative to 1992 levels. The second strategy is compatible with the longer-term goal of maintaining stable high levels of both spawning stock per recruit and yield per recruit. The time series analyses provide a useful tool for determining the appropriate short term catch or effort controls.
Biology, Oceanography; Environmental Sciences; Agriculture, Fisheries and Aquaculture
Sun, Chi-Lu, "Stock assessment and fishery management of the South Atlantic albacore (Thunnus alalunga)" (1995). Dissertations from ProQuest. 3384.