|| 要旨トップ | 目次 |||日本生態学会第65回全国大会 (2018年3月、札幌) 講演要旨
一般講演（口頭発表） J01-08 （Oral presentation）
Pacific bluefin tuna (PBF) was heavily exploited by various fisheries including purse seine (PS; in summer), set net (SN; in summer) and long line (LL; in winter). Price of a PBF caught by LL is high, price by SN is medium, and price by PS is cheapest. Using life table analysis, we calculate reproductive value (RV) and harvest value (HV) of each age and season. RV at age x is defined as the expected number of spawned eggs by a PBF from age x to death. HV at age x is defined as the expected value of a PBR that will grow and be caught in the future. The price of an immature PBF caught by PS is much cheaper than a HV. The price of a PBF caught by SN is much better than by PS. In conclusion, regulation of fisheries to immature fish especially in summer season increases the total yield.