Looking at the life cycle of its fish says a lot about what this Alaska hatchery does
KETCHIKAN, Alaska — Nestled along the Ketchikan Creek next to City Park is a small building that produces more than 500,000 king salmon per year.
Run by a two-person team, Deer Mountain Hatchery is the Southern Southeast Regional Aquaculture Association’s only hatchery dedicated solely to king salmon.
In the culmination of the hatchery’s biggest project of the year, 400,000 of those kings were transported by boat two weeks ago to upper Carroll Inlet, where they will be released into the ocean in mid-May.
Looking at the life cycle of these fish says a lot about what the hatchery does.
This particular group of king salmon began as eggs in August 2016. SSRAA harvested a batch of roughly 2.5 million eggs from kings returning to the nearby Whitman Lake Hatchery, where they were fertilized and placed in incubators for about nine months.
By the following April, the tiny fish had hatched and developed into fry – meaning that they were mature enough to be held in raceways and to feed on commercial fish food, rather than their yolk sacks.
Half a million of the fry were transported to Deer Mountain Hatchery. Here, they spent the better part of a year swimming in fresh-water circular tanks, which continuously circulate the water and allow the fish to exercise.
This spring, rising temperatures and light levels signaled to the young fish that it was time to transition to salt water, just as they would in the wild.
The kings’ transition to the ocean began about two weeks ago. Over the course of several mornings, the fish were pumped from an outdoor raceway, through a tube and into a metal tanker truck that previously had been used to carry de-icing fluid at Ketchikan International Airport.
The truck carried the fish to a dock at the Alaska General Seafoods plant on Stedman Street, where the fish were gravity fed into the hull of a boat, the Linda. With a few SSRAA staff members onboard, the Linda made the trip to SSRAA’s remote release site near the Swan Lake Power Station in upper Carroll Inlet.
According to Deer Mountain Hatchery Assistant Manager Matt Allen, SSRAA’s practice of having employees from various hatcheries pitch in on a project allows the hatcheries to take on large projects while keeping their staffs as small as possible.
“Being able to share labor responsibilities allows us to maintain a crew of (only) what we need,” Allen said.
At the remote release site, the kings were transferred to 40-by-40 foot saltwater net pens _ their first encounter with pure salt water. At about seven degrees Fahrenheit warmer than the water at Deer Mountain, the ocean water fires up the fish’s metabolism. During this stage, the fish are fed more food than ever and can double in size.
The kings will be released into the open ocean water in mid-May. They will then have to adapt to the demands of a totally alien environment.
“When we release them, they need to learn to become a wild fish,” Allen said. “They’ve been eating, you know, a commercial diet in a hatchery or in a net pen. When we release them, they have to figure out, ‘OK, what plankton can I eat? What fish can I eat? What crab or shrimp or squid can I eat?'”
According to Allen, these kings typically will stay in the southeast Alaska region, though some will enter the open ocean and travel great distances. They will eat a widely varied diet and spend much of their time feeding close to land. These behaviors stem not only from their species, but from their parent stock, which originally was harvested from kings native to the Chikamin River in the Misty Fjords National Monument.
While the struggling health of Alaska king salmon stocks has had a prominent place in recent headlines, SSRAA General Manager David Landis emphasized that hatchery salmon are distinct from wild salmon, and that SSRAA doesn’t aim to replenish any wild stocks.
“This just gives the commercial and sport fishermen an additional resource, besides those fish that spawn in the river system,” Landis said. “… They’re designed to be separate.”
SSRAA’s king salmon are harvested primarily by commercial trollers, who sell the fish for a high price. In southeast Alaska, troll fisheries occur in winter, spring and summer. Commercial seine and gill net, sport, charter, subsistence and personal use fishermen harvest king salmon as well.
Most of the surviving kings, guided by sense of smell, will return to their Carroll Inlet release site three to five years after their release in May. Like wild salmon, their aim will be to return to their birthplace to spawn. Unlike wild salmon, they will have entered a terminal harvest area, which means, in short, that many will be harvested by commercial fishermen.
Meanwhile, some fish belonging to the same brood year (members of the 2.5 million eggs the story began with) that were released at the Whitman Lake Hatchery will return to Whitman Lake, and some of those will be used as brood stock. Their eggs will be taken, and the cycle will begin again.