作 者 ：廖永岩*,许振煜,,吴邦臣
期 刊 ：生态学报 2010年 30卷 13期 页码：3396~3405
Keywords:Portunus sanguinolentus, salinity, temperature, survival, intake,
摘 要 ：盐度和温度，是影响蟹类分布、孵化、幼体发育、生长、性成熟、存活及摄饵的两个重要环境因子，设置0、5、10、15、20、25、30、35、40、45、50共11个盐度梯度（盐度差±0.5，每个盐度梯度8只蟹），0、5、10、15、20、25、30、35、40℃共9个温度梯度（温度差±0.5℃，每个温度梯度8只蟹），进行盐度和温度对红星梭子蟹(体重（125±11）g左右)摄饵和存活影响的研究，拟为进一步研究盐度和温度对红星梭子蟹分布、生长、幼体发育、低温保活等的影响提供基础资料。结果显示，盐度从30骤变时，15-40盐度蟹能存活5d以上，存活率达100%；15-45盐度蟹能摄饵，日平均摄饵量达1.32g以上。20-40盐度蟹摄饵明显，日平均摄饵量达3.22g以上。盐度从25以5/d渐变时，盐度10-45蟹均能存活5d以上，存活率达100%；盐度10-45蟹均有摄饵，但盐度15-40蟹摄饵较理想。温度从25℃骤变时，15-30℃蟹能100%存活5d以上。10℃以下及35℃以上，蟹在3d内全部死亡。15℃以上，蟹只要能存活，都有摄饵。25-30℃为蟹最适温度范围，蟹日平均摄饵量达3.55g以上。不超过30℃时，温度越高蟹摄饵量越大。从25℃以5℃/d渐变时，15-30℃蟹存活100%，10℃和35℃蟹存活75%；5℃以下及40℃以上蟹存活时间不超过30min。15-35℃蟹能摄饵。不超过30℃，温度渐变时也是温度越高，蟹日平均摄饵量越大。
Abstract:Temperature and salinity are two important environmental factors which can affect distribution, hatch, larval development, growth, sexual maturity, survival and intake of crab. The three-spot crab, Portunus sanguinolentus is a commercially important, edible crab which is distributed in the Pacific and Indian Ocean. Experiments were conducted to evaluate the effect of salinity and temperature on survival and food intake of Portunus sanguinolentus. Eleven salinity gradients including 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 as well as 9 temperature gradients including 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ and 40℃ were respectively designed. In each treatment, 8 crabs (wet weight averaged (125±11)g) were enclosed and their survival and feeding rate were examined. The results showed that, five days after the salinity acute changed from 30, the survival rates of Portunus sanguinolentus were 100% in 15-40. The Portunus sanguinolentus could feed at salinity of 15-45, the daily mean food intake was over 1. 32g. The proper food intake of survivor was at salinity of 20-40, the daily mean food intake was over 3.22g. With the gradual salinity changed of 5 /d from 25, the survival rates of Portunus sanguinolentus were 100% for five days in 10-45. The Portunus sanguinolentus could feed at salinity of 10-45, but the food intake was higher when it was at salinity of 15-40. This results showed that the proper salinity of survival and food intake of Portunus sanguinolentus was in 25-35 (P＜0.05). Five days after the temperature acute changed from 25℃, the survival rates of Portunus sanguinolentus were 100% in 15-30℃. They all died within three days below the 10℃ and over the 35℃. Over 15℃, if the crab can survive, they all could feed. The proper food intake of survivor was in 25-30℃, the daily mean food intake was over 3.55g. With the gradual temperature changed beginning from 25 at a rate of 5℃ variation per day, the survival rates of Portunus sanguinolentus were 100% in 15-30℃, 75% at 10℃ and 35℃. The survival time only lasted 30min when the temperature is below the 15℃ or over the 40℃. This results showed that the proper temperature of survival and food intake of Portunus sanguinolentus was in 25-35℃ (P<0.05), the optimal temperature was at 30℃ (P<0.05). The results indicated that the crab’s survival and feeding rate changed with the changing magnitude of salinity or temperature. In general, the crabs could survive in a wider salinity range when the crabs were subject to gradual changes of salinity as compared with those in acute changes (i.e., 10-45 in a gradually changing regime of 5 per day beginning from 25 vs. 15-40 in a acute changing regime beginning from 30 ). If the temperature changed acutely from 25℃ to below 10℃ or to above 35℃, the crabs all died within 3days. If the temperature changed gradually from 25℃ at a rate of 5℃ variation per day, 25% of the crabs died within 5 days in temperatures below 10℃ or above 35℃. In addition, in the conditions that salinity was acutely changed from 25 to 20-40, the crabs performed actively feeding and their daily feeding rate reached more than 3.22 g in average. In the case that temperature varied acutely, the crabs exhibited optimal intake of food at temperatures between 25℃ and 30 ℃, and their daily feeding rate reached more than 3.55g in average.
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