In 1995, the Federal Drug Administration put a kink in Utah's planned program for Strawberry Reservoir. It stopped the state's method of sterilizing fish . . . fish that were considered critical to future plans for Utah's No. 1 fishing hole.
To continue to sterilize rainbow trout would have taken millions more dollars than the Utah Division of Wildlife Resources had or would likely ever get.Even though the method had been used successfully for years, Utah was told to stop - under threat of severe penalties - its sterilization program.
This, of course, triggered the imagination of some of the state's brightest biologist.
An example: One thing that came out of it was a scientific-looking piece of equipment made from a children's phonograph, a roll of electrical tape, a few boards, a battery, an electrical cord and an electromagnet.
It is, says Eric Wagner, research biologist at the DWR's experiment station in Logan, the first step in getting back on track.
The experiment involves crossing diploid eggs with tetraploid sperm to come up with triploids fish - that is, a fish with different chromosome patterns that would make it sterile. Aside from that, it would look, swim, feed and taste like any other fish of the species.
Wagner says that studies have shown that shocking eggs at a certain stage of development - with such methods as heat or cold or chemicals or a change in the magnetic field - can produce the desired results.
"We know that the magnetic field is a very important part of our development. It's around us every minute of our lives. We also know that changing the field can have some beneficial results. Changing the field has shown, for example, a more rapid regeneration of damaged tissues," he adds.
"There was nothing available that would allow us to do this, so I built an experiment . . . and it works."
He subjected rainbow trout eggs to very low changes in the magnetic field. The phonograph turntable was necessary to keep the eggs rotating so they wouldn't become referenced to the field and resume normal patterns.
The first test, using DC power, was not very successful. From a tube of eggs, only three turned out to be triploids. He plans to try different voltages and even AC power.
Wagner knows it will work, it's a matter of finding the right combinations.
"Shocks, such as this, are not uncommon in nature. It's not unusual to find individual animals in the wild that are sterile. It's just that their numbers are low and survival is not high because they can't reproduce," he says.
"So we know it happens, we just have to find out how. We may manipulate the water the eggs are in, or reduce the calcium levels around the eggs. These might be other approaches."
Utah was using methyl testosterone on small fry. It was being added to the feed, fish would eat it and it would inhibit reproduction.
"We were getting close to 100 percent success using this method," says Wagner.
"The FDA has restrictions on testosterone, partly because of the abuse by Olympic athletes. They were also concerned about the residual effects of testosterone in stocked fish. The risk in our opinion was nil, but the FDA saw it differently. To try and get the drug approved would have taken millions (of dollars)."
Another approach the station is taking is creating hybrids, such as the "Brownbow," which is a cross between brown and rainbow trout.
If it can be raised efficiently, it would serve two purposes: one, hybrids are sterile, and two, biologist hope it would be more resistant to diseases such as whirling disease.
"There does appear to be one problem," Wagner points out. "Between 80 and 90 percent of the fish had cataracts. They look healthy and were fat, but had eye problems. It didn't appear to effect their feeding."
Under the management plan for Strawberry, fertile Bear Lake cutthroat and sterile rainbow were put into the lake. The cutthroat, a very aggressive fish, are there to keep the Utah chub population from exploding. The rainbow, a fast-growing, easy-to-catch fish, were put in the lake for the sportsmen to catch. Using fertile rainbow would result in cross-breeding and dilute the cutthroat strain.
Until a method of sterilization can be found, Utah has had to step up its planting program for cutthroat. Still, the absence of sterile rainbow throws the whole Strawberry plan off course.
In the meantime, Wagner will be experimenting with the turntable and magnet, and looking into other solutions to the sterile-fish problem.