Spatial and temporal distribution patterns of bigeye tuna (Thunnus obesus) in the Indian Ocean

Pei Fen Lee, I-Ching Chen, Wann Nian Tzeng

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The spatial and temporal distribution patterns of bigeye tuna (Thunnus obesus) in the Indian Ocean were studied based on catch data of Taiwanese longline fishery during the period 1985-1999. We used a geographic information system (GIS) to compile a fishery database to statistically explore the catch per unit effort (CPUE), mean weight distribution, and the relationship between distribution and environmental factors. Results indicated that bigeye tuna were mainly distributed in tropical waters between 10°N and 15°S, although some scattered instances of high catches appeared outside this range. Sea surface temperature (SST) was the optimal environmental factor for predictions of monthly CPUE, but not for the mean weight index which showed a broader pattern. The monthly mean weight index was not correlated with monthly CPUE except in Dec. and Jan. CPUE hotspots generally occurred between 10°N and 15°S, but hotspots for mean weight index were concentrated in the west of this geographical range. Temporal trends of the CPUE and mean weight indices showed regional differences. Most of the monthly mean CPUE values in the 5 ecoregions showed no significant temporal trends, while the mean weight index showed an increasing pattern. The distributional patterns shown by the CPUE and weight indices of bigeye tuna in the Indian Ocean were similar to those in the Pacific Ocean. Given the current population status and the increasing fishing intensity to meet public demand, conservation measures must be considered to ensure a sustainable fishery.

Original languageEnglish
Pages (from-to)260-270
Number of pages11
JournalZoological Studies
Volume44
Issue number2
Publication statusPublished - 2005 Apr 1

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Thunnus obesus
Indian Ocean
fisheries
environmental factors
ecoregions
Pacific Ocean
geographic information systems
surface temperature
prediction

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology

Cite this

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abstract = "The spatial and temporal distribution patterns of bigeye tuna (Thunnus obesus) in the Indian Ocean were studied based on catch data of Taiwanese longline fishery during the period 1985-1999. We used a geographic information system (GIS) to compile a fishery database to statistically explore the catch per unit effort (CPUE), mean weight distribution, and the relationship between distribution and environmental factors. Results indicated that bigeye tuna were mainly distributed in tropical waters between 10°N and 15°S, although some scattered instances of high catches appeared outside this range. Sea surface temperature (SST) was the optimal environmental factor for predictions of monthly CPUE, but not for the mean weight index which showed a broader pattern. The monthly mean weight index was not correlated with monthly CPUE except in Dec. and Jan. CPUE hotspots generally occurred between 10°N and 15°S, but hotspots for mean weight index were concentrated in the west of this geographical range. Temporal trends of the CPUE and mean weight indices showed regional differences. Most of the monthly mean CPUE values in the 5 ecoregions showed no significant temporal trends, while the mean weight index showed an increasing pattern. The distributional patterns shown by the CPUE and weight indices of bigeye tuna in the Indian Ocean were similar to those in the Pacific Ocean. Given the current population status and the increasing fishing intensity to meet public demand, conservation measures must be considered to ensure a sustainable fishery.",
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Spatial and temporal distribution patterns of bigeye tuna (Thunnus obesus) in the Indian Ocean. / Lee, Pei Fen; Chen, I-Ching; Tzeng, Wann Nian.

In: Zoological Studies, Vol. 44, No. 2, 01.04.2005, p. 260-270.

Research output: Contribution to journalArticle

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