Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean |
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Authors: | Kuo‐Wei Lan Ming‐An Lee Chin‐Pei Chou Ali Haghi Vayghan |
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Affiliation: | 1. Department of Environmental Biology Fisheries Science, National Taiwan Ocean University, Keelung, Taiwan;2. Center of Excellence for Oceans, National Taiwan Ocean University, Keelung, Taiwan;3. Taiwan Fisheries Sustainable Development Association, Keelung, Taiwan;4. Department of Fisheries, Faculty of Fisheries and Environment, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran |
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Abstract: | The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. |
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Keywords: | annual assemblage Atlantic behavior biological dynamics biology catch per unit effort climate fish fishery habitat indices level of organization longline method migration NAO oceanography pelagic population region remote sensing taxon temperature thermocline time scale tropical tuna |
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