A New Assessment Approach Using Fuzzy Surplus Production Model to Evaluate the Albacore Stock in the Indian Ocean

印度洋長鰭鮪資源的模糊生產量模式評估分析

汪淑慧(Shu-Huei Wang) ； 許建宗(Chien-Chung Hsu) ； 劉錫江(Hsi-Chiang Liu)

《臺灣水產學會刊》 28卷4期 (2001/12) Pp. 329-338

https://doi.org/10.29822/JFST.200112.0006

摘要

長鰭鮪是重要的溫帶高產鮪類之一。自1970年代起，臺灣成為在印度洋使用鮪延繩釣漁具開發長鰭鮪的主要國家（產量約佔總印度洋年產量之85%）。為評估印度洋長鰭鮪資源，傳統和模糊餘量生產模式被應用於評估分析。臺灣1979年至1997年每日報表資料，先經以年、月、小漁區和標的魚種等因數做泛線性模式法標準化後之單位努力漁獲量，被用來做為資源量指標。結果顯示時序列資源量指標在1979年至1987年間呈波動且穩定地處於高水準狀態，接著自1988年起下降至1995年後，又呈上升趨勢。經以傳統和模糊餘量生產模式分析結果顯示，最大持續生產量分別為27,717 公噸及27,248公噸，模糊餘量生產模式估得之限界為25,728公噸和30,651公噸之間。這些估值都高於1992年以後的總年產量，顯示族群在低開發中，且因上升的資源量指標趨勢和遠低於最大持續生產量的漁獲水準，本資源在目前漁獲水準下應有樂觀的投射結果。

關鍵字

長鰭鮪 ； 傳統餘量生產模式 ； 模糊餘量生產模式 ； 最大持續生產量

並列摘要

Albacore is one of the important temperate and productive species. Since 1970s, Taiwan has been the leading nation exploiting the species using longline in the Indian Ocean (about 85% total annual catch). For assessing the stock status, a traditional Schaefer surplus production model and a fuzzy surplus production model are used for this purpose. Daily catch and effort data extracted from logbooks from 1979 to 1997 of Taiwan tuna longline fishery is used to derive the abundance index that is standardized by the general linear model with year, month, subarea and target species factors. The annual catches from longline and surface gears were used to fit these production models. The results show that a standardized abundance index was obtained with fluctuated stably in a high level from 1979 to 1987 then decreased from 1988 to 1995, and increased after 1995. The maximum sustainable yield (MSY) estimated by Schaefer production model is 27,717 mt. The MSY estimated by fuzzy surplus production model ranged from 25,728 to 30,651 mt with increasing vagueness and point estimated at 27,248 mt. Since 1992, the catches have been far below MSY, indicating that the stock may be under exploited status and an optimistic projection with a current catch level may be resulted from the increasing abundance index trend and catch level under MSY.

並列關鍵字

Albacore ； Schaefer surplus production model ； fuzzy surplus production model ； Maximum sustainable yield (MSY)