Effects of Hook and Bait Types on Bigeye Tuna Catch Rates in the Tuna Longline Fishery

다랑어 연승어업에서 눈다랑어 어획률에 미치는 낚시 및 미끼의 효과

  • Kim, Soon-Song (National Fisheries Research and Development Institute (NFRDI)) ;
  • Moon, Dae-Yeon (National Fisheries Research and Development Institute (NFRDI)) ;
  • An, Doo-Hae (National Fisheries Research and Development Institute (NFRDI)) ;
  • Hwang, Seon-Jae (National Fisheries Research and Development Institute (NFRDI)) ;
  • Kim, Yeong-Seung (National Fisheries Research and Development Institute (NFRDI)) ;
  • Bigelow, Keith (Pacific Islands Fisheries Science Center) ;
  • Curran, Daniel (Pacific Islands Fisheries Science Center)
  • Received : 2007.11.16
  • Accepted : 2008.05.30
  • Published : 2008.06.30

Abstract

A pelagic tuna longline research cruise in the eastern and central Pacific Ocean from September to October of 2006 was conducted to compare catch rates with the use of different hook type and bait combinations. Traditional tuna hooks (J 4) and three circle hook types (C15, C16, C18), along with five bait types (chub mackerel (CM), jack mackerel (JM), milkfish (MF), sardine (SD), and squid (SQ)) and hook number as a proxy for hook depth were evaluated for their effect on bigeye tuna catch rates (fish per 1,000 hooks) using Generalized Linear Models (GLMs). Results from 28 sets indicated significant differences in bigeye catch rates between individual longline sets and hook number. The GLM explained 33% of the deviance in bigeye catch rates with these two factors. An alternative model formulation included bait type which had a small effect (explaining 2.7% of the deviance) on catch rates. Hook type had a negligible and non-significant effect in the GLMs. These results indicate that all of the hooks and baits tested are equally effective at catching bigeye tuna and that hook number (depth) was the paramount operational factor in explaining bigeye tuna catch rates.

다랑어낚시 및 사용미끼에 따른 어획률을 비교하기 위해, 2006년 9~10월간 태평양 중동부 해역에서 다랑어연승 시험조사가 수행되었다. 일반선형모형(GLM)을 이용하여 재래식 다랑어낚시 1종(J4)와 환형낚시 3종(C15, C16, C18), 미끼 5종(고등어(CM), 전갱이(JM), 밀크피쉬(MF), 정어리(SD), 오징어(SQ)) 및 낚시심도를 나타내는 낚시 순번들이 눈다랑어 어획률(1,000낚시당 마리수)에 미치는 효과를 평가하였다. 총 28회 조업에서 낚시순번 간 눈다랑어 어획률에는 유의한 차이가 인정되었다. GLM분석에서 낚시순번에 의한 눈다랑어 어획률 편차는 33%로 나타났다. 미끼 종류 간 어획률 차이는 그 편차가 2.7%로 적게 나타났고, 낚시형 4종 간 그 차이는 매우 적어 유의하지 않게 나타났다. 따라서, 낚시형 및 미끼 종류의 선택은 다랑어 연승어업에서 눈다랑어 어획률 차이에 영향을 주지 않는 것으로 평가되었으나, 어획수심을 나타내는 낚시순번은 눈다랑어 어획률에 영향을 주는 요인으로 판단되었다.

Keywords

Acknowledgement

Supported by : National Fisheries Research and Development Institute

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