Wildlife of Lake Clark: Salmon, Wolves, Bears, Sheep, Moose and Caribou

Salmon hold up the food web of Lake Clark National Park and Preserve in Alaska. Each year between 150 thousand and 3.1 million sockeye salmon return to the park's creeks, rivers and lakes, and the National Park Service (NPS) describes them as important to the region's culture, ecology and economy. Here is how six of the park's animals fit in.

Sockeye salmon (Oncorhynchus nerka). NPS Photo/D. Young.

Sockeye salmon

Sockeye, also called red salmon, are a keystone species. They are anadromous: they hatch in fresh water, migrate to the ocean in their first or second summer, spend one to three years growing there, then return to their birthplace to lay eggs and soon die. Few species bring nutrients from the ocean into rivers, lakes and forests the way salmon do, and they feed life at every level of the food chain. People in the area have lived on them for centuries, and they also provide commercial fishing jobs in Southwest Alaska.

Gray wolves

Wolves live in family packs. Biologists have found four to six packs in the park and preserve, with about four to ten members each. Territories here are larger than those of other Alaskan packs, so there are fewer packs in the same area; they average 1000 square miles. Territory size depends on what the wolves hunt. Packs that eat salmon roam less, because even in spring wolves can dig salmon carcasses out of the lake ice, which makes salmon a long-term food source.

Many young wolves leave their packs to find a mate and a new territory; a few have gone as far as Bethel, 230 miles west of the park's boundary. NPS/J. Mills.

Brown bears

Bears' behavior and diet depend on where they live. On the coast, food is packed into a small space: protein-rich plants in salt marshes, clams on tidal flats, berries on hillsides and, in late summer, salmon in the rivers. NPS compares the coast to a city of grocery stores. Inland, in boreal forest and tundra, food is scarcer and more spread out, so bears eat more roots, insects and berries, travel farther to find salmon, and are fewer in number. The park supports a healthy brown bear population; 95 percent of the brown bears in the United States live in Alaska.

A brown bear (Ursus arctos) in a salt marsh meadow on the Lake Clark coast. NPS/J. Pfeiffenberger.

Dall sheep

Dall sheep live farther north than any other North American wild sheep, and Lake Clark is the southwestern limit of their range in Alaska. They graze tiny alpine plants in summer, when food is plentiful, and in winter eat dry, frozen grasses, sedges, lichens and moss. Only a few of the park's mountains hold them: too high a peak has too little vegetation, and too close to the coast, long winters bury food under deep snow. The park's sheep number about 1,000. Good places to look are the steep slopes of Tanalian Mountain, or around Twin Lakes where they come to salt licks.

Moose

The largest member of the deer family, moose live in the park's forests, tundra and wetlands. Only bulls grow antlers, up to 6 feet (1.8 meters) wide. In spring and summer they eat sedges, horsetail, grasses and water plants; in fall and winter they travel far for willow, birch, aspen twigs and other shrubs. They are active by day, especially at dawn and dusk. Their long legs let them wade lakes, rivers and deep snow. Their eyesight is poor, but they hear well and have an excellent sense of smell. They can be very aggressive and reach speeds of up to 35 miles per hour.

A bull moose. NPS Photo/J. Mills.

Caribou

Caribou are the only deer in which both males and females can have antlers. With moose they are the only deer in the Lake Clark area. They range over the foothill lakes and tundra plains, eating lichens and dried sedges in winter and willows, grasses and flowering plants in summer. Their large, scoop-shaped hooves help them walk on snow and tundra, paddle across water and dig for food. Studies of the Mulchatna Caribou Herd show it has shrunk from around 200,000 animals in 1999 to closer to 14,000. NPS notes that there may be more factors behind the decline, such as changing food resources, and that caribou herds have varied in size through history.

A bull caribou. NPS/J. Frank.

Sources

• National Park Service, Lake Clark National Park and Preserve, "Wildlife of Lake Clark"; rewritten in hubnx's own words.