No studies of population structure in Chinese waters could be located. Results of stock assessments for the South China Sea have been presented at regional workshops, with results from 2009 available (FAO, 2010) but it is unclear if they resulted from a yield per recruit model or expert judgment. A modified depletion model has been used to assess another species – neon flying squid – in the region (Chen et al., 2008), as has a dynamic factor analysis (Chen, 2010).
No formal scientific advice is published but a Chinese Squid Jigging Technical Group has collected sampling and fishing data since 1995 (Chen et al., 2008). Studies have suggested a limitation on the number of vessels fishing during the winter season when juveniles are growing or a closure of part of the fishing grounds would assist in increasing the resource (Zhang et al., 2008; Song et al., 2008).
No assessment or management reference points are known to be in place.
Studies in several areas have shown a decrease in mean body size and size at sexual maturation in females (Li & Huang, 2011; Zhang et al., 2008; Huang, 2008). At a 2009 workshop, Chinese scientists classified the Mitre squid fishery in the Northern South China Sea as overexploited and the fleet as overcapacity. In addition, five-year trends in catch rates and a survey index were decreasing (FAO, 2010).
Catches of squid increased rapidly in the early 2000s but from 2005 have been on a stable or slightly decreasing trend. Increased cephalopod catches in the South China Sea in the past were attributed to changing fishing techniques and not to increased abundance (Guo & Chen, 2000).