Salmon are a crucial link between Sitka National Historical Park and its surrounding marine environment. Salmon and several other species of fish are anadromous, meaning their life cycle is completed by returning from the ocean to spawn in the river where they were born. Returning salmon transport energy and nutrients from the ocean to the freshwater environment. This cycle is vital to the health of coastal ecosystems, increasing stream productivity and benefitting resident fish habitat. For the salmon, coming home means contributing to the community where their lives began.
Pink salmon (Oncorhynchus gorbuscha) are the most common salmon species in the Indian River. These fish are nicknamed “humpbacks” or “humpies” due to the pronounced humped back that males develop during spawning migration. Humpies complete their lifecycle in two years, including the time they hatch from eggs until their return as adults to spawn. After the eggs hatch, juvenile pinks immediately begin their migration to the ocean and begin to grow quickly. Humans and other predatory animals rely on this ocean phase of the salmon lifecycle for harvesting mature salmon. During spawning season from mid- July through September, the pink salmon return to the same river to produce their own young.
Other species use the river as habitat for migration, spawning, incubation of eggs, and rearing of young. Three other species of Pacific salmon (chum, coho, and king), two species of trout (cutthroat and rainbow), and one char (Dolly Varden) spawn in the Indian River. Pacific salmon, including pink, die after spawning while trout and char may return to the river several times to spawn. Fish enter the intertidal and lower segments of the Indian River, but only pink and chum have been observed spawning in the river itself.
The Indian River is also an important habitat for non-migrating fish species. Coastrange sculpin, three-spined stickleback, and resident rainbow trout live in the river year round. These species, like anadromous fish, feed on rich populations of invertebrates in the river. Their presence contributes to a diverse aquatic web, where fish species act as both predators and prey. The three-spined stickleback is endemic to the Southeast Alaska archipelago and north coast of Canada.
Salmon carry nutrients that have accumulated during their time in the ocean and are deposited back into the system during spawning migration and finally death. Their bodies feed countless piscivores (fish eaters) like mammals and birds. The larger animals carry carcasses onto the stream bank or nearby vegetation, where they are partially eaten and left to fertilize the forest.
Did You Know?
Sitka National Historical Park has the distinction of being the oldest federally designated park in Alaska. It was designated as a park by President Benjamin Harrison on June 21, 1890. More...