中西北太平洋紅肉旗魚時空分布與資源評估

Spatio-temporal distribution and stock assessment of striped marlin (Kajikia audax) in the western and central North Pacific Ocean

連永祥(Yung-Hsiang Lien)

指導教授 ： 孫志陸

國立臺灣大學/理學院/海洋研究所/博士(2013年)

https://doi.org/10.6342/NTU.2013.01071

摘要

紅肉旗魚是高度洄游性魚種，在北太平洋廣泛分布於熱帶和溫帶海域。本研究利用漁獲資料和衛星遙測環境因子資料，包括表水溫(SST)、葉綠素濃度(CHL)、混合層深度(MLD)和海面高度距平值(SHA)，透過泛加成模式(generalized additive model, GAM)分析，探討中西北太平洋紅肉旗魚系群的棲地特性。分析結果顯示SST能解釋大部分的變異，可作為預測紅肉旗魚棲地的最好指標。系群相對豐度的分布顯示紅肉旗魚漁場具季節性南北移動的特性，且系群在夏威夷海域附近有較高的豐度。系群棲地環境之探討，顯示紅肉旗魚偏好棲息的環境分別為SST在23-26°C，MLD在30公尺以淺, CHL約0.08 mg m-3的海域，對SHA則無明顯的偏好範圍。
本研究另將台灣鮪延繩釣漁業在中西北太平洋的漁獲量與努力量資料透過泛加成模式進行標準化分析，考量因子包括年效應、月效應、漁區效應、表水溫效應及因子間之交感效應。標準化後之台灣鮪延繩釣紅肉旗魚單位努力漁獲量(catch per unit effort, CPUE)，連同日本遠洋、日本近海及夏威夷鮪延繩釣漁業標準化CPUE，利用非平衡生產量模式(ASPIC)評估紅肉旗魚資源現況。結果顯示中西北太平洋紅肉旗魚最大可持續生產量(MSY)為4,812公噸，相對系群生物量(B2010/BMSY)為0.20，相對漁獲死亡率(F2009/FMSY)為2.53，推斷中西北太平洋紅肉旗魚系群目前處在已過漁且過漁中之狀態。未來資源量變動之投射分析結果建議總允許漁獲量應降低至每年1,700公噸，以使該資源能永續利用。

關鍵字

紅肉旗魚 ； 時空與環境因子 ； 系群分布 ； 資源評估 ； 非平衡生產量模式

並列摘要

Striped marlin, Kajikia audax, is a highly migratory species distributed throughout tropical and temperate waters in the western and central North Pacific Ocean (WCNPO). In this study, the habitat preferences of striped marlin in the WCNPO were examined using generalized additive models (GAM). Fishery catch rates were modeled as a function of remotely-sensed environmental covariates, including sea surface temperature (SST), chlorophyll-a concentration (CHL), mixed layer depth (MLD) and sea-surface height anomalies (SHA). SST explained the largest proportion of the deviance, and was therefore considered the best predictor for the habitat of striped marlin. Spatial distributions of the relative density of striped marlin indicated that there is a seasonal north–south migration, and that the highest densities occur in the central North Pacific Ocean. The preferred habitat characteristics of striped marlin in high density areas were identified as SST between 23-26°C, MLD within 30 m depth, and CHL around 0.08 mg m-3. There was no evident preferred range for SHA.
Catch per unit effort (CPUE) data for striped marlin from the Taiwanese longline fleet in the WCNPO were standardized using GAM, with SST, year, month, fishing area, and the interactions used as the explanatory variables. The standardized CPUE series for this fleet, as well as those from the Japanese distant-water, Japanese coastal, and Hawaiian longline fleets were used in a non-equilibrium surplus production model (ASPIC) to assess the stock status of striped marlin in the WCNPO. Results showed that the maximum sustainable yield (MSY) estimated for this stock was 4,812 tons, and that the stock was both overfished and subject to overfishing. The values of B2010/BMSY and F2009/FMSY were estimated at 0.20 and 2.53, respectively. The projection analysis suggested that the total allowable catch (TAC) should be reduced to 1,700 tons per year for sustainable use of this resource.

並列關鍵字

striped marlin ； spatial and environmental factors ； stock distribution ； stock assessment ； non-equilibrium production model

參考文獻

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