Lake Washington's sockeye run still down

In the midst of their peak seasonal return to Lake Washington, thousands of sockeye salmon pass through the Ballard Locks each day, yet their numbers don't compare with recent runs. State fisheries managers anticipate another low season with little chance of recreational anglers having their catch.

"They're doing a lot better than they were the last two years, but we are still well below a fishable run," said Steve Thiesfeld, fish biologist with the Washington Department of Fish and Wildlife.

To estimate the sockeye population, fish counters with the state along with the Muckleshoot Indian Tribe watch from the underground viewing windows at the Locks every day from mid-June through July, the peak of the run.

So far 40,000 fish have traversed the Locks on their way to Lake Washington and the Cedar River, where they spawn and die. To ensure enough fish successfully spawn each year, managers don't allow recreational fishing until at least 350,000 fish have passed through.

The sockeye haven't reached fishable levels since 2006, Thiesfeld said. "Even the most recent information on the fish run suggests we can't get there this season."

The sockeye face myriad obstacles, all of which affect their survival.

Most Lake Washington sockeye start in the Cedar River, while others are released from local hatcheries. The juvenile fish, referred to as "fry," must travel downstream, all the while dodging predators, disease and human encroachment on their stream beds.

To reach the ocean, the fish must pass through a series of man-made and potentially treacherous obstacles, including the Lake Washington Ship Canal, which connects Lake Washington to Puget Sound.

"A natural shoreline would have marsh edges and lots of places for them to hide from predators," said Aaron Bosworth, fish biologist with the Department of Fish and Wildlife. "But with all the docks, riprap banks, concrete bulkheads and big boats, there's not a lot of places for shelter."

Upon reaching the Ballard Locks, the small salmon can be seen shooting out of the white fish-passage tubes installed by the Army Corps of Engineers.

The salmon who make it to the ocean spend two to three years competing for food, avoiding predators and dealing with unpredictable ocean conditions before returning to the lake.

At the Locks, the returning sockeye must find and navigate the small fish ladder, while avoiding harbor seals.

Once in Lake Washington, the salmon confront other stresses.

"Lake Washington, like many water bodies, is undergoing a lot of changes which could impact the sockeye," said Thomas Quinn, a fisheries biologist at the University of Washington. "You have shoreline development, cool and warm climate years, and water-quality issues."

Moreover, Lake Washington sockeye aren't native to the lake but were introduced by the state in the 1930s.

"The idea was to create a fishery in Lake Washington and provide nutrient input," said Melissa Reeder, fish counter with the department. When the fish die after spawning upriver, their bodies provide nourishment to the plants and trees on the riverbank, Reeder said. "Their presence here increases the quality of life in the watershed."

Despite the low runs at Lake Washington, Columbia River sockeye are returning in record numbers, with as many as 30,000 fish a day passing through Bonneville Dam.

Why the success there and not Lake Washington?

"We really don't know," said Robert Nelson, spokesman for the department. "They're fish, and unfortunately they don't talk."

Cassandra Brooks: 206-464-2311 or cbrooks@seattletimes.com