Spawner-Recruit Analysis of Portunus (Portunus) Trituberculatus (Miers, 1876) in the Case of Stock Enhancement Implementation: a Case Study in Zhejiang Sea Area, China

摘要

Portunus (Portunus) trituberculatus (Miers, 1876) is one of the most important economic species in the East China Sea. In recent years, the catch of P. trituberculatus in this sea area dramatically increased. Some researches owing this to the implementation of stock enhancement, and encourage its development. However, besides the increased catch, the potential impact of releasing on the spawner-recruit (S-R) relationship is neglected. In this research, we analyzed the S-R relationships using the data of P. trituberculatus in a typical sea area (Zhejiang seas area) in the East China Sea from 1995 to 2015, and found that stock enhancement can greatly impact the original S-R relationship. We separated above period into 2 stages (the 1st stage is from 1995 to 2010, and the 2nd stage is from 2011 to 2015), which represented the periods without and with the additive effect of stock enhancement on wild population, respectively. Different S-R models are necessary for wild population and release stock. Two Ricker S-R models were built for these 2 stages, which are R= 10.53 Se-0.00032 S and .R= 14.26 Se-0.00019 S The survival rate of the release stock is much higher than that of wild population, and the reproductive rate is also high for the release stock. The S-R relationships of release stock and wild population are different. The reproductive rate (R/P) of release stock is higher than that of wild population.