It sounds easy: Put in small fish, let 'em grow into bigger fish and then catch 'em.
That's not taking into account, of course, things like birds, temperatures, bad health, no food, and worse, bigger fish with an appetite for smaller fish - any fish.For years, the fish trucks back down boat ramps in the spring and fall and dropped millions of fish off at their new residency.
That seemed fine at the time. Tried and proven methods are hard to argue with. Then something happened. The Class of '95 came up missing - most of it anyway. There were bigger fish from earlier plants and smaller fish from later plants, but the size-class from '95 was not showing up.
The result: new planting methods at Strawberry - the same ones used two weeks ago to plant half a million sterile rainbow.
The rainbows were brought to Strawberry from Utah Division of Wildlife hatcheries in late June - not the spring or fall. They were not unloaded at the ramps but were placed in barges. They were not unloaded in deep water or in cold water, and not in a few concentrated spots. These fish were strategically placed in areas that afforded the best chance for survival - something the Class of '95 was not able to do.
It took five long days to get the fish moved, said Bob Spateholts, special project biologist for the DWR. But they're in, and the long-term objectives set for Strawberry 10 years ago are back in place.
When the lake was treated and all the fish killed back in 1990, the plan was to plant Bear Lake cutthroat, sterile rainbow and kokanee salmon. They planted cuts because they are an aggressive predator on small fish, mainly chubs; the rainbow because they are a preferred game fish; and the kokanee as a second game fish.
Three years ago, Utah was told its method for sterilizing fish could no longer be used. So, for two years there have been no rainbow planted.
According to Roger Wilson, special project leader at Strawberry for the DWR, the fish come from rainbow stock that was adapted to spawn in the fall instead of the spring. This made it possible for the DWR to get the eggs in December, which in turn made it possible to plant the fish last week.
To get the sterile fish, said Wilson, a California company developed an accepted method of producing sterile rainbow - even better, all female sterile rainbow. To begin with, it came up with a way for female fish to produce sperm.
"Where the male produces an `X' and `Y' chromosome, these female fish produce a sperm with only the `X' chromosome," said Wilson. "Because female fish only produce the `X' chromosome, only female fish are produced.
"The eggs are then put through a process called `heat shock.' This is where the eggs are put in hot water. This results in fish that are `triploid' or fish with three instead of two chromosomes. This interferes with fertilization. So what you have is sterile fish with female characteristics"
One advantage to this, besides rapid growth, is there are no false spawns with sterile males trying to fertilize the eggs of fertile females.
No one knows what happened to the Class of '95, but it is widely held that the planting procedure enabled birds and larger fish to eat the new arrivals.
The planting method used for the sterile rainbow is the same one used for age classes '96 and '97.
"And," said Spateholts, "our gill-net checks this spring show that we're getting a good return of fish in those size classes, which tells us that the method works."
The fish were brought in from two hatcheries in fish trucks and then loaded onto barges. With between 8,000 and 10,000 fish onboard, the boat headed for pre-determined locations around the reservoir, primarily shallow areas where there is currently an abundance of food, good water quality and protection from predators.
The fish that were planted were between four and five inches.
"Because this is such a prime time to plant fish, we expect to see growth of about one inch per month, and in some cases two inches," Spateholts said. "By fall these fish will be 10 to 14 inches, and by the fall of 1999, we expect these fish to be 16 to 18 inches. At least that's what we saw with other sterile fish. This is the first time we've planted the triploids, but we expect similar growth."
Earlier, 500,000 cutthroats were planted using this same system. This fall, the DWR will plant another 2 million cutthroats. Spateholts pointed out that the cutthroat planting was stepped up when the DWR lost its source of sterile rainbow.
The fact that the lake is now full for the first time - 17,000 surface acres or 1 million acre feet - large sections of new shoreline have been flooded, which has resulted in an abundance of food, not only for larger fish but also for the new plants.
Because of the number of fish and the new planting policy at Strawberry, consensus is that the catch rate will continue to get higher in the coming years.
Currently, because the fish are scattered and fish numbers are down becuase of the gap in planting, fishing has been spotty, but it is showing signs of improving. Boat fishermen have been doing well trolling pop gear, needle fish and triple teasers.
Plans are to purchase another 500,000 sterile rainbow, at a cost of around $20,000, this fall for planting in the summer of 1999.
Strawberry remains Utah's No. 1 fishery. The last detailed report, taken in 1995, showed 415,000 angling days were spent on the reservoir. By comparison, Lake Powell was second with 330,000 angling days. Consensus is those numbers are higher today.