June 21, 2012 | Vol. 110, No. 25

Cold water a possible factor with low fish return

The Crystal Lake Hatchery began operation in Petersburg in 1973 and is one of the oldest operating hatcheries in southeast Alaska.

Crystal Lake Hatchery Manager Loren Thompson describes the new heat transfer system for the hatchery. This system heats the ambient water to a more comfortable temperature for the growing King Salmon.

“This hatchery was started as a sport fish hatchery,” Crystal Lake Hatchery Manager Loren Thompson explained. “It still is, it’s the only one in southeast Alaska.”

According to the Southern Southeast Regional Aquaculture Association, the facility was first stocked with Chinook from the Columbia River. Andrews Creek fish were used at the hatchery and spread from there as the initial stock used at many different Chinook projects across southeast Alaska.

Crystal Lake was chosen as a hatchery site because of the existent hydroelectric plant and water source.

“Every year we release 600,000 Crystal Creek Kings here in Crystal Creek,” Thompson said. “We also release 200,000 Cohos here; 500,000 Chickamin Chinook are incubated, reared and later released at Neets Bay and another 500,000 Crystal Creeks are released at Anita Bay.”

With 1.8 million fish being released, an average return has been approximately 1,000 for the last few years.

“As soon as these fish hit salt water, they imprint on the nearest fresh water influence,” Thompson said. “They will return to this influence naturally.”

When eggs are taken from the Andrews Creek area and are released here, this is where they return. Thompson said they are very accurate about their return.

This process will take anywhere from zero to seven years, usually about four years and that is the optimum time of return according to Thompson.

“Each year when they return, we harvest the eggs, fertilize them and incubate them and raise them in the raceways.” Thompson explained. “The return over the last 12 plus years has not been constant.”

Crystal Lake Hatchery has had to resort to getting eggs from DIPAC in Juneau and NSRAA’a Hidden Falls hatchery.

“They initially got their eggs from here,” Thompson said. “The stock is the same. This is helpful when we have problems, they can help us and vice versa.”

When Crystal Lake has a low return of fish, it will impact the amount of fish available for fishing. “When there are more years with low returns, it will see a significant shortage,” Thompson stated.

Thompson explained that most of the slow returns have been attributed to the cold winters seen in the recent past.

“The ambient water currently comes into the hatchery at 2.7 degree Celsius,” he said. “Zero degrees C. is freezing and the colder water can make the fish lethargic and they will go dormant.”

Crystal Lake Hatchery is now, for the first time, using a heat exchanger and at present is able to heat the ambient water from 2.7 degrees to 6.5 degrees C.

“This difference in temperature will speed up the metabolism of the fish,” Thompson said. “They eat more and get bigger faster.”

Thompson explained that in the beginning, when fuel costs were lower, the hatchery would use boilers to heat the water coming from the slough.

“With the rising costs of fuel the boilers haven’t been used in approximately 15 to 20 years,” he explained. “With this new heat exchanger we are hoping the fish will be healthier and bigger at release.”

The results of this new equipment will not been seen for several years, when returning adults are tallied up from the releases of smolt that are raised with the use of the heat exchanger, Thompson explained. “We are hoping to produce healthier fish and raise the survival rate for improved returns.”

The Southern Southeast Regional Aquaculture Association secured funding for this new heat exchanger at the price of $180,000 which includes equipment, installation along with piping and everything else needed to get this into operation.

“This process will take a long time,” SSRA Production Manager Bill Gass said. “If the results we are seeing now in the growth rate are any indication, we will see a larger rate of return in four to five years.”

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