秋季我国近海不同海域短蛸角质颚形态学研究

Beak morphometrics of short arm octopus(Amphioctopus fangsiao) in different sea areas of China in autumn

根据2015年10—11月在黄海、东海和南海北部渔业生产期间采集的393尾短蛸样本,通过标准化方法对不同海域短蛸的10项角质颚形态值进行了差异性分析,同时建立判别函数以区分不同群体。结果显示,东海和黄海样本短蛸个体大小较为类似,南海个体明显较小;经角质颚形态值标准化处理,南海海域个体的角质颚形态比其他2个海域更小;方差分析显示,3个海域短蛸角质颚形态存在显著差异,其中除了下翼长外,东海与黄海个体的角质颚形态值均不存在差异,而南海与其他2个海域的角质颚形态值均存在显著差异;主成分分析结果发现,第一主成分因子均为下颚形态值,第二、第三主成分均为上颚形态值;通过逐步判别分析,选取了6项角质颚形态值建立判别函数,判别正确率在80%以上;回归树分析结果发现,短蛸的下颚形态值(下头盖长和下翼长)能够更快速地辨别不同海域的短蛸。研究表明,因摄食和栖息环境的不同,不同海域短蛸角质颚形态存在较大差异,因此可通过角质颚的形态来判别短蛸的种群。

Short arm octopus, Amphioctopus fangsiao, is widely distributed along the coast of China, and also is one of the important commercially explored cephalopod species in China. Based on 393 samples of A. fangsiao collected along the coast of China, including the Yellow Sea, East China Sea and South China Sea during October to November in 2015, the variation of ten standardized beak morphometrics was studied among the different areas and the discriminant analysis was also established based on the beak morphology. The results showed that the body size of A. fangsiao located in Yellow Sea and East China Sea was similar, and the individuals in South China Sea were smaller than other areas; the standardized beak in South China Sea was also smaller than other two areas.ANOVA test showed that the beak morphometrics in East China Sea and Yellow Sea had no significant difference except for lower beak wing（P0.01）, and beak morphometrics in South China Sea had significant difference compared to other two areas（P0.01）. Principal component analysis suggested that the lower beak mophometrics represented first component factor, and upper beak morphometrics represented the second and third component factors for all the individuals from three different areas. Six beak morphometrics were selected for the stepwise discriminant analysis, and the correct classification rate was over 80% for three different areas. The result of classification tree analysis showed that lower beak morphometrics（lower hood length and lower wing length） can be a good criterion for quick identification of the octopus from different areas. In conclusion, this study has confirmed that the beak morphology has different patterns in different areas due to the varied environments, and also showed that beak is a suitable criterion for identifying the population variation for cephalopods.