Abstract: This study measured δ¹³C and δ¹⁵N in muscle, liver, kidney, lung, hair, whisker and nail from juvenile and adult captive spotted seals Phoca largha after feeding Clupea harengus and Mallotus villosus for more than 6 months to produce the fractionation in each tissue. Meanwhile, this study estimated the food sources for the wild spotted seals from Liaodong Bay, in terms of δ¹³C and δ¹⁵N fractionations in muscle, liver and kidney of wild spotted seals and its potential foods in Liaodong Bay. The results showed that the highest δ¹³C 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 δ¹⁵N 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 δ¹³C values in captive pup were -22.4‰, -23.0‰ and -22.1‰ in muscle, kidney and liver, respectively. The δ¹³C value in milk was -24.8‰. The δ¹³C 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 δ¹³C 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 cephalopoda and shrimps as well.

Key words: water status indicator., apple tree, drought stress