Journal of Tropical Oceanography ›› 2015, Vol. 34 ›› Issue (6): 64-72.doi: 10.11978/2015038cstr: 32234.14.2015038

• Marine Biology • Previous Articles     Next Articles

Salinity effects on growth and enzyme activity of juvenile Sepia pharaonis

LE Ke-xin, JIANG Xia-min, WANG Yuan, PENG Rui-bing, JIANG Mao-wang, HAN Qing-xi   

  1. School of Marine Sciences, Ningbo University, Ningbo 315211, China
  • Received:2015-03-16 Revised:2015-06-20 Online:2015-11-10 Published:2015-11-24

Abstract: To investigate salinity effects on growth and enzyme activity of juvenile Sepia pharaonis, manipulative laboratory experiments were conducted. These experiments revealed the effects of abrupt and gradual changes of salinity on survival rate, specific growth rate, weight gain rate, hepatosomatic index, and enzyme activity (superoxide dismutase, alkaline phosphatase, glutamic oxaloacetic transaminase, glutamic-pyruvic transaminase). The results showed that abrupt salinity change had significant effects on larval survival rate and behavior after cultivation of 21 days (p<0.05). Optimum survival rates of juvenile cuttlefish were obtained when cultivated at salinity of 24‰ and 27‰ (75.56%±6.94%~77.78%±6.94%). Specific growth rate and weight gain rate were the highest at the salinity of 27‰. The hepatosomatic index increased with salinity increase, and achieved the highest value at the salinity of 30‰. Gradual change of salinity also had significant influence on survival rate, specific growth rate, weight gain rate, hepatosomatic index, and enzyme activity (p<0.05). Optimum survival rate (87.78%±1.92%) was obtained at the salinity of 24‰. Specific growth rate (6.88%•d-1±0.13%•d-1) and weight gain rate (180.96%±5.13%) were the highest at the salinity of 27‰, whilst the highest hepatosomatic index was observed at salinity of 30‰. SOD enzyme activity declined and then increased following the rising of salinity from 18‰ to 33‰, with the lowest value at salinity of 27‰. GOT, GPT and AKP enzyme increased and then decreased; GOT and GPT enzyme activity were the highest when the salinity was 24‰, whereas AKP enzyme reached the maximum value at salinity of 30‰. Therefore, the suitable and optimal salinity values were 21‰~30‰ and 24‰~27‰, respectively, under abrupt salinity change. Suitable and optimal salinity values were 18‰~33‰ and 24‰~27‰, respectively, under gradual salinity change. We concluded that juvenile cuttlefish can live under a wider range of salinity and that we can improve its survival rate with very gradual salinity change.

Key words: Sepia pharaonis, juvenile, growth, behavior, metabolic enzyme

CLC Number: 

  • P735.541