풀무치(Locusta migratoria)는 메뚜기과에 속하는 곤충으로 70% 이상의 단백질을 함유하고 있어 식사료용 곤충으로 이용 가능성이 높다. 그러나 풀무치의 대량생산을 위한 연중사육 관련 연구는 미흡하여 사육방법 정립, 먹이원 선발 등이 필요하다. 본 연구에서는 풀무치의 연중사육을 위한 방법으로 사육밀도에 따른 생육 특성과 최적 산란처를 찾기 위해 상토, 오아시스 등을 이용하여 산란 특성을 조사하였다. 풀무치의 생육 온도는 28℃, 습도는 65% 내외로 유지하고 처리구별 생존율, 탈피횟수, 크기, 무게 등을 측정하였다. 사육밀도별 약충 기간은 32일 소요되었고, 생존율은 82~90 %였으며, 성충 기간은 110~120일 소요되었다. 산란처별 난괴 길이는 33~49mm였으며, 부화 후 생존율을 72~82%였다.

The maturation and spawning of black scraper, Thamnaconus modestus were studied using samples collected monthly from March, 2015 to February, 2016 in the coastal waters off Middle East Sea, Korea. The gonadosomatic index (GSI) of female was the highest in June. The spawning periods lasted from March to September based on histological observation of female gonad development. The percentage of sexually mature females estimated from a logistic function was over 50% for the size group 18.02 cm (total length, TL). The size of eggs spawned was between 0.40 to 0.58 mm. Fecundity varied between 185,648 and 9,747,250 eggs. The relationship between the fecundity and TL of the fish was expressed in the fecundity equation as F = 0.0297TL5.4835.

Yield per recruit model is the most popular method for fisheries stock assessment. However, stock assessment using yield per recruit model can lead to recruitment overfishing as this model only considers the maximum yield per recruit without spawning biomass for reproduction. For this reason, spawning biomass per recruit model which reveals variations of spawning stock biomass per fishing mortality (F) and age at first capture (tc) is considered as more proper method for stock assessment. There are mainly two methods for spawning biomass per recruit model known as age specific selectivity method and knife– edged selectivity method. In the knife–edged selectivity method, the spawning biomass per recruit has been often calculated using biomass per recruit value by multiplying the maturity ratio of the recruited age. But the maturity ratio in the previous method was not considered properly in previous studies. Therefore, a new method of the knife–edged selectivity model was suggested in this study using a weighted average of the maturity ratio for ages from the first capture to the lifespan. The optimum fishing mortality in terms of F35% which was obtained from the new method was compared to the old method for small yellow croaker stock in Korea. The value of F35% using the new knife–edged selectivity model was 0.302/year and the value using the old model was 0.349/year. However, the value of F35% using the age specific selectivity model was estimated as 0.320/year which was closer to the value from the new knife–edged selectivity model.