西非沿岸乌贼角质颚形态及生长特征

The Morphology and Growth Characteristics of Beaks of European Common Cuttlefish (Sepia officinalis) in the Coast of West Africa

中文关键词: 乌贼  角质颚  形态参数  生长特征

英文关键词: Common cuttlefish (Sepia officinalis)  Beak  Morphological parameter  Growth characteristics

中文摘要:

      乌贼(Sepia officinalis)是生活在大西洋西岸的重要头足类之一，研究乌贼角质颚形态及生长特征有利于对其的开发利用。本研究根据2015年在毛里塔尼亚附近海域生产期间所获得的乌贼渔获样本，对乌贼角质颚的各项形态参数进行描述，探究不同胴长和不同性腺成熟阶段角质颚生长情况的差异，并估算乌贼个体的大小。通过对乌贼上、下颚各长度指标的比值比较发现，乌贼角质颚下颚的长度比值波动较大，较不稳定。t检验表明，将各项形态参数除以胴长消除样本规格影响差异后，乌贼雌性个体在角质颚的各项形态参数上均极显著大于雄性(P<0.01)；方差分析及多重比较(LSD法)表明，随着胴长的增加，乌贼的各个角质颚的形态参数也极显著增加(P<0.01)。在性腺成熟期Ⅱ~Ⅳ中，乌贼角质颚的形态参数随着性腺成熟度的增加而显著增加(P<0.05)，但性腺成熟度为Ⅴ期的个体的角质颚形态参数却显著小于前面几期(P<0.05)。主成分分析显示，第一主成分的负载绝对值最高的指标为上头盖长(Upper hood length, UHL)和下脊突长(Lower crest length, LCL)；第二主成分下喙长(Lower rostrum length, LRL)和下喙宽(Lower rostrum width, LRW)，利用主成分分析得到的前2个主成分可以对乌贼的胴长进行估算。研究表明，同一种类不同性别的乌贼个体角质颚形态参数及其比值存在特异性，研究结果为西非沿岸乌贼类分类及生态研究提供基础资料。

英文摘要:

      Common cuttlefish (Sepia officinalis) is one of the most important economic and ecological species in the West African coastal waters. Studying the morphology and growth characteristics of its beak is beneficial for common cuttlefish´s development and utilization. This study analyzed beak morphological parameters and their ratios based on the samples collected by the Chinese trawlers in 2015 in coastal waters of West African Mauritania, and studied the beak growth variations in different mantle length groups and different gonadal maturity stages. Morphological parameters of beaks were used to estimate the size of the cuttlefish. The results showed the length ratio indices of the lower beak were not stable, and that the beak morphological parameters of female were significantly higher than the male after eliminating the effect of the sample size differences by dividing the mantle length (P<0.01). The ANOVA and the Least Significant Difference (LSD) analysis showed that morphological parameters of the common cuttlefish beaks significantly increased with the growth of mantle length (P<0.01) and gonad maturity stage Ⅱ~Ⅳ (P<0.01). However, beaks in the gonad maturity stage V were significantly smaller than those in the previous periods (Ⅱ~Ⅳ, P<0.05). Principal component analysis showed that upper hood length (UHL) and lower crest length (LCL) had the highest loading coefficient in the first principal component, and that lower rostrum length (LRL) and lower rostrum width (LRW) had the highest loading coefficient in the second principal component, which can be used for the mantle length estimation. This study provides basic biology information for the classification and ecological research about common cuttlefish in the coast of West Africa.