The Indian Ocean is the second-largest tuna fishing ground in the world, accounting for approximately 1.2 million tonnes (23%) of the estimated 5.2 million tonnes of global commercial tuna catch in 2023. This study examined the relationship between tuna catches, specifically skipjack, bigeye, and yellowfin tunas, and prey biomass (Nautical Area Scattering Coefficient, NASC) estimated from acoustic surveys conducted in the southwestern Indian Ocean from 20 April to 15 May 2019. Environmental variables were derived from the Copernicus Ocean Model, and tuna length data from the IOTC. The estimated total tuna catch in the study area was approximately 166,400 tonnes, with the northwestern region showing the highest catches and NASC values. Tuna catches increased with NASC; however, the relationship was non-linear. While skipjack showed no significant correlation with NASC, bigeye and yellowfin tunas exhibited weak but significant positive correlations. Environmental analysis revealed that the northern waters had high surface temperatures, low salinity, and low oxygen levels, with mid and deep layers characterized by low temperature, salinity, oxygen, and chlorophyll. These findings offer a foundation for understanding tuna distribution in relation to prey and environmental conditions, highlighting the need for future species- and fishery-specific studies to support sustainable tuna resource management.

서 론
재료 및 방법
    과학음향조사
    음향 자료 분석
    다랑어 어획 자료
    해양환경 자료 처리
    자료 시각화와 통계 분석
결과 및 고찰
    인도양 다랑어 어획량
    다랑어의 먹이 생물량
    다랑어 어획량과 먹이 생물량의 공간적 관계
    IOTC 해역과 조사 해역의 다랑어 체장 및 체중 비교
    조사 기간 동안의 해양환경
    인도양의 다랑어 어업 및 어획량
결 론
사 사
References

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