Like clockwork, almost, the Issaquah Salmon Hatchery turns into a hive of activity in early September, as the chinook run brings the famous fish to Issaquah Creek.

Recent rains are also helping to drive the mighty chinook, or king, salmon to return home to the hatchery.

The hatchery opened its fish ladder on Monday, Sept. 7, and now an estimated 300 chinook are in the facility’s holding pond.

These chinook are the first wave of the 2009 season’s salmon run.

They are usually joined by some sockeye, with coho expected to arrive in a few weeks.

The hatchery raises chinook and coho salmon and expects the 3- to 5-year-old fish to return to Issaquah Creek from now through November or early December.

The hatchery saw the 2009 season’s first chinook – a female estimated to be 25 pounds – on August 24.

More than 4,600 chinook have been counted passing through the Hiram M. Chittenden Locks to date, and Muckleshoot Tribal officials, who conduct the salmon counts, estimate the run size will reach roughly 5,500 – less than half of an average return.

Meanwhile, the trend for this year’s coho return looks strong.

While still early in the run, the early estimates are that more than 40,000 coho will pass through the Locks this fall. If that number holds up, that would put the run at nearly double an average return.

The news is not so encouraging for the sockeye return. This year’s count of sockeye through the Locks suggests that this year’s run will be the lowest on record since the counts began in 1972.

This year’s estimated sockeye run count was about 20,000 – well below last year’s record-low count of 34,000.

Most of the chinook and coho passing through the Locks are bound for the Issaquah Hatchery.

Others return to Bear Creek, the Cedar River and the other major streams of the Lake Washington/Lake Sammamish Watershed.

Some chinook also return to a small hatchery at the University of Washington.

The hatchery also expects to spawn kokanee from Jacobs, Ebright and Lewis Creeks in November. The eggs could be reared at the Issaquah hatchery or another state hatchery. The kokanee will then be released back into their home creeks as fry.

The hatchery is free to the public during daylight hours, seven days a week.

Hatchery personnel expect to spawn 1,000 chinook and 1,200 coho this year, with a goal of collecting 2 million chinook and 1.5 million coho eggs.

This season’s salmon return is on schedule for the 2009 Issaquah Salmon Days Festival on Oct. 3 and 4.