应用碳氮稳定同位素研究斑海豹(Phoca largha)的食性

Feeding habits of the spotted seal Phoca largha by stable carbon and nitrogen isotopes analysis

通过检测以毛鳞鱼和大西洋鲱饲养6个月以上的幼年和成年豢养斑海豹(Phoca largha)肌肉、肝脏、肾脏、肺、毛发、触须和趾甲等组织的δ13C和δ15N值,获得各组织的分馏系数,结合辽东湾海域斑海豹肌肉、肝脏和肾脏等组织及辽东湾海域潜在食物的δ13C和δ15N值,推测斑海豹在辽东湾海域的食物来源。结果发现:豢养斑海豹对食物中的δ13C值各组织分馏系数依次为触须(3.5‰)>毛发(3.2‰)>趾甲(3.0‰)>肌肉(1.3‰)>肺(1.0‰)>肝脏(0.5‰)>肾脏(0.3‰);对食物中的δ15N值各组织分馏系数依次为肾脏(2.8‰)>肝脏(2.7‰)>肌肉、趾甲和触须(均为2.6‰)>肺(2.4‰)>毛发(1.8‰);豢养斑海豹幼崽肌肉、肾脏和肝脏组织的δ13C值分别为-22.4‰、-23.0‰和-22.1‰,母兽乳汁的δ13C值为-24.8‰;辽东湾海域成年斑海豹肌肉、肾脏和肝脏组织的δ13C值分别为-18.6‰、-19.1‰和-18.7‰。通过豢养斑海豹肌肉组织δ13C的分馏系数(1.3‰)推测辽东湾海域斑海豹的食物以鱼类为主,喜食中上层和中下层鱼类,同时也摄食一些头足类和虾类。

This study measured δ^13C and δ^15N in muscle, liver, kidney, lung, hair, whisker and nail from juvenile and adult captive spotted seals Phoca largha after feeding Clupea harengus and Mallotus viUosus for more than 6 months to produce the fractionation in each tissue. Mean- while, this study estimated the food sources for the wild spotted seals from Liaodong Bay, in terms of δ^13C and δ^15N fractionations in muscle, liver and kidney of wild spotted seals and its po- tential foods in Liaodong Bay. The results showed that the highest δ^13C value in captive spotted seals was in whisker （3.5‰） , followed by hair （3.2‰） , nail （3.0‰）, muscle （1.3‰）, lung （1.0‰）, liver （0.5‰） and kidney （0.3‰）. The highest δ^15N value in captive spotted seals was in kidney （2.8‰）, followed by liver （2.7‰）, muscle （2.6‰）, nail （2.6‰）, whisker （2.6‰）, lung （2.4‰） and hair （1.8‰）. The δ^13C values in captive pup were -22.4‰, -23.0‰ and -22.1‰ in muscle, kidney and liver, respectively. The δ^13C value in milk was -24.8‰. The δ^13C values in wild adult spotted seals from Liaodong Bay were -18.6‰, -19.1‰ and -18.7‰ in muscle, kidney and liver, respectively. According to the fractionation （1.3‰） of δ^13C in captive spotted seal muscle, the estimated food sources for wild spotted seals from Liaodong Bay were mainly from fishes （especially pelagic and meso-demersal fishes） , and some cepha- lopoda and shrimps as well.