Gray wolves in coastal Southeast Alaska and British Columbia are a genetically distinct subspecies (Canis lupus ligoni) that have unique connections to the ocean, both in habitat and diet. In the past 10 years, this subspecies has incorporated more marine species into their diet, especially sea otters (Enhydra lutris). In central Southeast Alaska there are specific populations in three locations: Juneau (wolf=22), Gustavus (wolf=11, otter=17), and Pleasant Island (wolf=15, otter=67). Wolves in Juneau subsidized most of their diet with terrestrial prey, Gustavus wolves feed mainly on terrestrial prey and marine opportunistic diet, and Pleasant Island wolves, situated between Gustavus and Juneau, eat a high amount of opportunistic marine prey such as otters and only occasional terrestrial prey. The mean wolf δ¹³C and δ¹⁵N in Juneau was -25.0, 4.70 ‰, in Gustavus -22.2, 7.88 ‰, and in Pleasant Island -17.5, 11.3 ‰, with Pleasant Island wolves displaying enriched isotopes. Sea otters in Gustavus and Pleasant Island displayed δ¹³C and δ¹⁵N of -15.2, 11.2 ‰ and -15.1, 11.3 ‰, respectively, indicative of the high contribution of sea otters into Pleasant Island wolves and only limited contribution to Gustavus wolves. Heavy metal analysis indicates a significant difference in cadmium, mercury, selenium, and vanadium among the 3 groups of wolves. The high concentrations of both vanadium and manganese in the Pleasant Island wolves may be related to high concentrations and physiological utilization of both elements by marine invertebrates. The selenium to mercury ratios in all wolves suggests a potential mercury toxicity. Cadmium in Pleasant Island wolves in particular were significantly different than all other wolves in the study. This correlated with the higher cadmium concentrations found in sea otter fur. The combined stable isotopes and heavy metal analyses present the importance of the marine diet in select populations of coastal grey wolves in southeast Alaska.

Amy C Hirons

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