Journal of Tropical Oceanography ›› 2019, Vol. 38 ›› Issue (6): 62-73.doi: 10.11978/2019004CSTR: 32234.14.2019004

Special Issue: 南海专题

• Marine Biology • Previous Articles     Next Articles

Age and growth of Sthenoteuthis oualaniensis based on statolith microstructure in the South China Sea

LIU Yu1,2,3, WANG Xuehui1,3,4(), DU Feiyan1,3, LIU Bilin2, ZHANG Peng1,4, LIU Mengna1,2, QIU Yongsong1   

  1. 1. South China Sea Fisheries Research Institute, China Academy of Fishery Sciences, Guangzhou 510300, China
    2. College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China
    3. Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, Guangzhou 510300, China
    4. Key Laboratory of Open-Sea Fishery Development, Ministry of Agriculture and Rural Affair, Guangzhou 510300, China
  • Received:2019-01-06 Revised:2019-03-25 Online:2019-11-20 Published:2019-11-26
  • Contact: Xuehui WANG E-mail:wxhscs@163.com
  • Supported by:
    National Science and Technology Support Program(2013BAD13B06);National Science and technology basic resources survey(2017FY201405);National Science and technology basic resources survey(2018FY100105);Science and Technology Planning Project of Guangdong Province, China(2014A020217011);Central Public-interest Scientific Institution Basal Research Fund,CAFS(2019HY-JC0203);Central Public-interest Scientific Institution Basal Research Fund,CAFS(2019GH02);Central Public-interest Scientific Institution Basal Research Fund,CAFS(2019HY-XKQ03)

Abstract:

Age and growth rate are key parameters in fish stock assessment and management. Sthenoteuthis oualaniensis has a short life cycle and a fast growth rate. We employ statolith microstructure to study the difference in age composition, gender and growth of the squid collected from October 2016 to September 2017 by falling-net in the South China Sea in order to study their age and growth. The results show that the age of medium cohort squid ranged from 48d to 125d and that the dominant age was from 61d to 80d. There were significant differences in the composition of female and male ages; age of dwarf cohort squid was between 44d to 95d, and the dominant age was between 51d to 70d. The difference in age composition between male and female individuals is significant. The estimated incubation period for the medium cohort samples was from July 2016 to July 2017; the peak hatching dates were distributed in the months of January and from July to August; the incubation period of the dwarf cohort was from June to October 2016 and from December 2016 to February 2017, and their peak hatching months were January and August. The mantle length, body mass and age of different individuals in the medium cohort could be fit in logarithm and linear relationship. The mantle length and age of different individuals in the dwarf cohort were fit in logarithm and logistic relationship, while the body mass and age were fit in logistic relationship. Our findings indicate that the growth rate of the dwarf group was higher than that of the medium group. The growth rate of the female was lower than that of the male in the dwarf group, but it was the opposite in the medium group. Through the analysis of statoliths growth pattern, we can learn about the age composition of the squid, estimate their hatching time, select their appropriate growth equation, and estimate their growth rate, to provide basic data for fishery biology.

Key words: Sthenoteuthis oualaniensis, statolith, age, growth, the South China Sea