Defense Date

4-24-2025

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Biology

First Advisor

Amy C Hirons, Ph.D.

Second Advisor

Dimitrios Giarikos, Ph.D.

Third Advisor

Gretchen H. Roffler, Ph.D.

Fourth Advisor

David W. Kerstetter, Ph.D.

Keywords

Gray wolf, trace elements, Southeast Alaska, stable isotope ratios

Abstract

Gray wolves (Canis lupus), northern sea otters (Enhydra lutris) and salmon (Oncorhynchus spp.) play vital roles in southeast Alaska, yet all are exposed to trace element (TE) bioaccumulation. This study examines dietary patterns and TE accumulation in four northern Lynn Canal wolf populations (Douglas Island, Juneau, Gustavus, and Pleasant Island) using stable isotope analysis (SIA) (δ13C and δ15N) and TE assessments. SIA revealed that wolves in Juneau and Douglas Island primarily consumed terrestrial prey, whereas wolves in Gustavus and Pleasant Island exhibited enriched isotopic signatures indicative of a marine-based diet, particularly sea otters. Trace element analysis showed higher concentrations (Al, Cd, Cr, Co, Fe, Mn, Hg, Mo, Se, and V) in wolves with marine-based diets, highlighting bioaccumulation risks related to this marine subsided diet. Both sea otter populations demonstrated higher values compared to wolves for Cd, Se, and V. Douglas Island and Juneau wolves consume less marine prey but will opportunistically eat salmon mainly during the fall runs. Sixteen TE concentrations were analyzed across seven tissues from two Alaskan salmon species (chum (O. keta) and pink (O. gorbuscha)) revealing tissue-specific variation in metal accumulation, with kidney and liver having the highest concentrations. These findings suggest that salmon may serve as a pathway for TE transfer within the food web. Notably, the Se:Hg molar ratio suggested a heightened potential for mercury toxicity in all wolf population’s whereas all sea otters and salmon were outside the risk. Understanding how dietary habits influence contaminant exposure is critical for assessing ecological risks and informing conservation strategies.

ORCID ID

https://orcid.org/0009-0000-3979-3050

Download
Share Feedback

Share

COinS