This study evaluated catch selectivity differences between sea pike (Sphyraena japonica) and Spanish mackerel (Scomberomorus niphonius) using a modified codend with square mesh side panels in bottom trawl. Sea trials were conducted with the covered codend technique widely used to estimate codend selectivity curves at the coastal sea of Yokji-do, Gyeongsangnam-do, from December 2024 to January 2025. Selectivity curves were fitted using a B-spline model for sea pike and a probit model for spanish mackerel. The estimated 50% retention lengths ( ) were 26.88 cm for sea pike and 42.92 cm for Spanish mackerel, with selection ranges () of 2.42 cm and 10.76 cm, respectively. Spanish mackerel was shown the broader and more gradual selectivity curve, while sea pike showed steeper selectivity. This study found that selectivity changes depending on the change in the net structure of the trawl tip. In addition, a difference in selectivity was observed for two species with different morphological characteristics.

서 론
재료 및 방법
    시험 어구
    시험 방법
    망목 선택성 곡선 추정 방법
결 과
    해상 시험 결과
    망목 선택성 곡선의 추정
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References

• 김성훈(국립부경대학교 해양생산시스템관리학부 교수) | Seonghun KIM (Professor, Department of Marine Production System Management, Pukyong National University, Busan 48513, Korea) Corresponding author
• 백세나(국립부경대학교 일반대학원 해양생산관리학부 수산물리학전공 학생) | Sena BAEK (Graduate Student, Department of Marine Production Management major of Fisheries Physics, Pukyong National University, Busan 48513, Korea)