METAL Research Topics

Our research currently focuses on mercury concentrations and stable isotope signatures in seals and sea lions and their prey to help understand how heavy metals move within ecosystems and how they may impact conservation of piscivorous marine mammal species.

We also focus on assessment of diet composition using stable isotopes, body condition and general health assessment of marine wildlife, and adaptive biochemistry and metabolism in fasting marine mammals.

Marine Mammals

Within the Order Carnivora are a group of "fin footed" mammals or pinnipeds. There are 3 families of pinnipeds: Otariidae (sea lions and fur seals), Phocidae (seals), and Odobenidae (walrus). Our research currently focuses on Otariids and Phocids.

  • Common Name: Steller Sea Lion

    Scientific Name: Eumetopias jubatus

    Native Names: Wiinaq (Alutiiq) | Qawax (Aleut) | Kai (Haida) | Taan (Tlingit) | Uginaq (Yup'ik)

    Distribution: Across the Pacific rim of fire, California to northern Japan

    Life Span: 30 to 40 years

    Size:
    Pup 23 kg
    Adult female 350 kg (2.9 m)
    Adult male 1120 kg (3.25 m)

    Fun Fact: Largest Otariid males weigh over 2400 pounds and are three times the size of females at a dainty 800 pounds.

    Distribution map and additional information at the NOAA Marine Mammal Laboratory.

  • Common Name: Northern Fur Seal

    Scientific Name: Callorhinus ursinus

    Native Names: Aatak (Alutiiq)

    Distribution: Across the Pacific rim of fire, California, Western Canada, Alaska, Aleutians, Russia, Japan. Breeding colonies Probilofs.

    Life Span: 30 to 40 years

    Size:
    Pup 4.5-5.5 kg
    Adult female 30-50 kg (1.42 m)
    Adult male 185-275 kg (2.13 m)

    Fun Fact: Following weaning at 4 months of age, young fur seals may stay out to sea for 1 to 2 years before returning to their home rockery where they were born.

    Distribution map and additional information at the NOAA Marine Mammal Laboratory.

  • Common Name: Harbor Seal

    Scientific Name: Phoca vitulina

    Native Names: Isuwig (Alutiiq)

    Distribution: Across the northern hemisphere, subpolar to temperate zones.

    Life Span: 30 to 40 years

    Size:
    Pup 8 kg
    Adult female 80 kg (1.7 m)
    Adult male 140 kg (1.9 m)

    Fun Fact: Largest Otariid males weigh over 2400 pounds and are three times the size of females at a dainty 800 pounds.

    Distribution map and additional information at the NOAA Marine Mammal Laboratory.

  • Common Name: Bearded Seal

    Scientific Name: Erignathus barbatus

    Distribution map and additional information at the NOAA Marine Mammal Laboratory.

Ecotoxicology

High trophic-level marine predators, such as Steller seal lions, may be vulnerable to the potential impacts of exposure to heavy metals that accumulate in marine food webs. We focus on the monitoring of contaminant concentrations in the animals' tissues to understand a) the movement of contaminants through these high latitude food webs, and b) the potential for bioaccumulation and biomagnification of heavy metal contaminants to impact human and wildlife health.

  • High mercury exposure and tissular concentrations are neurotoxic to humans and other fish-eating mammals. Methylmercury exposure has also been shown to impact birth weight and immune function.

  • Selenium, which is present in a marine diet and binds to mercury in some scenarios, may provide some protection from the toxic effects of mercury. We will measure the concentration of selenium in whole blood samples collected to help us understand the potential mitigating effects that this element may have on mercury toxicity in Alaska pinnipeds.

  • Organic pollutants such as organochlorines (OC) act as endocrine (hormone) disruptors that impact reproduction and healthy fetal development. We are particularly interested in whether there may be OC levels of concern in Alaskan pinnipeds and how the synergistic effects of multiple contaminants may negatively impact health and reproduction of Alaskan species.

Trophic Assessment

Population & Ecosystem Health