Experiment was set up to analyze bycatch and discards situation including snow crap Chionoecetes opilio of whelk trap. Four types of trap were used: drum type trap with PE net; drum type trap with PBS net; cylinder type trap with PE net; and cylinder type net with PBS net. Three funnels were attached in drum type trap and two funnels were used in cylinder type trap. A fleet of traps was consisted with one hundred traps. 25 traps of each type were set on a line in repeated sequence. Field experiments were conducted with 6 fishing operations in the Uljin waters, East Sea in July 2014. Catch of target whelks were 173,261 g and catch rate was 48.7% of total catch, while bycatch were 182,571 g, 51.3% of tatal catch. The catch rate of bycatch was 2.6% higher than that of target catch. Bycatch weight of snow crap was the highest as 142,987 g and formed about 40.2% of total catch, followed giant octopus, Enteroctopus dofleini, 31,762 g (8.9%). Bycatch rate of cylinder type trap was 2.3 times higher than that of drum type trap. Discard rate (discard/(discard+landing)) was 43.6%. Discard rate was the highest at cylinder type trap with PBS net as 63.1%, followed cylinder type trap with PE net as 47.9%, drum type trap with PE net as 33.4%, the lowest at drum type trap with PBS net as 22.1%.

The mesh selectivity of drum net traps for Buccinum opisoplectum Dall caught in the eastern sea of Korea was described. Several experiments were conducted between July 2003 and March 2004 and the data obtained from the experiment was fitted by SELECT (Share Each Length class's Catch Total) model with unequal fishing and sampling efforts. The selection curve was determined to be 'estimated fishing efficiency' by model deviance rather than AIC. However the fishing efficiency between 20mm and 35mm mesh size did not seem to be different. The L50 lengths of the selectivity for the 55mm and 75mm mesh size were 65.4mm and 96.0mm, respectively.

동해안의 연안성 어족인 빨간횟대에 대해 망목크기 등을 달리한 8종류의 장구형 통발을 사용하여, 2003년 6월부터 12월까지 총 6차례에 걸쳐 어선 2척을 용선하여 조업한 어획실험으로부터 망목선택성 곡선을 구하여 합리적인 자원관리에 대한 기초 자료를 구하고자 하였다. 망목 크기가 20mm와 35mm인 두 통발의 빨간횟대 어획물로부터 체장에 따른 어획비율의 차이에 대해 특별한 경향을 발견할 수 없었다. 망목 크기가 20mm와 55mm인 두 통발의 경우에 대해 SELECT방법을 이용하여 equal split model 과 estimated split model을 적용한 결과, AIC 값이 적은 전자가 더 적절한 모델이므로, 빨간횟대의 경우는 이들 두 통발에 대한 입망률의 차이는 없는 것으로 나타났다. 망목 55mm의 통발에서 SELECT 모델로 구한 50% 어획될 빨간횟대의 전장은 22.0cm였다. 망목 크기가 20mm, 35mm, 55mm인 통발의 어획 자료에 Kitahara의 방법으로 logistic식을 적용하여 추정된 선택성 곡선식은 와 같았고, 현재 규정 망목 크기인 35mm 장구형 통발에 대해 50% 어획될 빨간횟대의 전장은 21.4cm이었다.