秘鲁外海茎柔鱼肌肉组织的能量积累

能量积累是表征生物体身体能量储备水平的重要指标之一,对寿命短、生长快且终生一次繁殖的头足类属种的表征作用尤显重要。本实验根据我国远洋渔业鱿钓渔船于2014年6-8月在秘鲁外海(10?26?S~17?17?S,79?17?W~82?39?W)作业期间随机采集的茎柔鱼(Dosidicus gigas)样本173尾(雌性107尾,雄性66尾),利用数学统计方法和组织能量密度测定技术,分析了该柔鱼个体的体重-胴长生长和胴体、足腕、尾鳍等肌肉组织的能量密度及其能量积累过程。结果显示,茎柔鱼雌雄个体的胴长、体重分别为(262.12±38.33)mm、(541.69±251.69)g,以及(251.37±31.90)mm、(449.78±179.99)g;雌雄个体的体重-胴长生长存在显著性差异(P0.05)。雌雄个体肌肉组织能量密度均以胴体的为最高,分别为(20.56±1.12)k J/g和(20.67±0.76)k J/g;足腕次之,分别为(20.09±1.25)k J/g和(19.95±0.87)k J/g;尾鳍最低,分别为(19.92±1.05)k J/g和(19.63±0.96)k J/g;同一组织雌雄个体间的组织能量密度无显著性差异(P0.05)。胴体、足腕、尾鳍等组织间的能量积累差异性显著(P0.05),胴体是最大的能量积累单元。其中,雌性个体胴体、足腕、尾鳍三组织的能量积累占比分别为63.14%、25.23%和11.63%;雄性个体的分别为65.89%、22.91%和11.20%。此外,胴体、足腕、尾鳍肌肉组织的能量随着个体生长积累显著(P0.05),并且这些肌肉组织的能量积累自低纬度向高纬度海域显著增加(P0.05),表明秘鲁外海茎柔鱼肌肉组织的能量积累过程是一个索饵育肥及其生长的过程。

Energy accumulated in the somatic tissues of the jumbo squid, Dosidicus gigas, off Peru

Energy accumulation is a vital index to indicate the level of reserve for organisms, especially for semelparous cephalopod species due to their short life-span and fast growth. In this study, using the mathematical methods and technology of energy-density determination, the relationship between body weight and mantle length, as well as the energy accumulation of somatic tissues including mantle, arms, and fins, were investigated for the jumbo squid, Dosidicus gigas, off Peru. The squid specimens were randomly sampled from the catch of a Chinese jigger fleet during the fishing season from June to August 2014, in the high sea off Peru (10°26°S-17°17°S, 79°17°W-82°39°W), and a total of 173 specimens were collected (107 females, 66 males). The results showed that the averages of both mantle length (ML) and body weight (BW) in female D. gigas were (262.12±38.33) mm and (541.69±251.69) g respectively; while in males, the values were (251.37±31.90) mm ML and (449.78±179.99) g BW respectively. The effect of sex on the exponent "b" of the BW-ML relationship was significant, suggesting that there was a significant difference in the body growth between female and male individuals. The maximum energy density was detected in the mantle tissue for both female and male individuals, with an average of (20.56±1.12) kJ/g and (20.67±0.76) kJ/g respectively; followed by the arm tissue, with an average of (20.09±1.25) kJ/g and (19.95±0.87) kJ/g respectively. For the fin tissue, the energy density was detected at the minimum value, with an average of (19.92±1.05) kJ/g and (19.63±0.96) kJ/g for female and male individuals respectively. For the same somatic tissue, there was no statistical difference in the energy density between females and males (P>0.05). The energy accumulated in different somatic tissues, however, was significantly different (P<0.05), and the mantle tissue was showed the highest energy accumulation. In females, the percentage of energy accumulation was about 63.14%, 25.23%, and 11.63% for the mantle, arms, and fins respectively. In males, the percentages were about 65.89%, 22.91%, and 11.20% for the mantle, arms and fins respectively. Meanwhile, the energy accumulated in the soma of the mantle, arms, and fins significantly increased with body growth for both female and male individuals (P<0.05), and the energy significantly increased along with the distribution from lower to higher latitudes (P<0.05). These findings indicate that the process of energy accumulation in the somatic tissues of D. gigas off Peru is the procedure for feeding and body growth.