Fewer Fish in Strawberry

By Bob Spateholts, UDWR Strawberry Project Biologist
     There is a lot going on with management of the Strawberry Reservoir fishery. The DWR is adapting our programs to maximize the quality of the fishery into the future. Public support for our management program has been outstanding so far. We need to keep the public informed, and welcome and respond to feedback. I'd like to give an update of what's happening in 1998.

Triploid Sterilized Rainbow Trout
     The Division of Wildlife Resources is planning to stock half a million rainbow trout in Strawberry in June. These fish have been sterilized by immersing the fertilized eggs in heated water, which alters the number of their chromosomes so they can't reproduce. They will be tested in April to verify the percentage of sterilization is high, so that they will not cross with the cutthroat in Strawberry. The rainbows will be about 5 inches at stocking, and should grow about an inch a month. A few may start showing up in the catch by fall.
     Rainbow trout typically occupy the shallow shoreline areas and weedy bays. They are excellent fighters and get fat and feisty. Rainbows provide an alternative harvest that buffers the take of Bear Lake Cutthroat.
The stocking of triploid sterile rainbows in 1998 will be an experiment. We may continue to stock them if they have satisfactory survival, growth and returns to the creel. Rainbow stocking will no longer be effective if chub numbers multiply and take over the weedbeds. We are several years away from this situation, but the chubs are there and are increasing.

Chub Abundance and Control
     The objective of the 1990 chemical treatment of Strawberry Reservoir was 99% removal of nongame species. The rotenone killed far more than 99% of chubs and suckers. We didn't see any rough fish for 2 1/2 years following the treatment. The extremely few survivors have now reproduced, and at present chubs make up somewhat less than 10% of the weight of fish in the the reservoir. At this level, competition with trout is not a problem.
     Bear Lake cutts and kokanee were chosen as the major species for Strawberry over the long term because we anticipated that chubs would eventually come back. The cutts and kokes will not be as severely impacted as rainbows are by competition, and should be able to maintain a good quality fishery in spite of large rough fish populations. The Bear Lake cutts are eating some chubs. Presently, the large cutts eat more smaller trout and kokanee, which are more numerous than the nongame fish. As chubs become more abundant they will be more heavily preyed upon by large trout.
     We are evaluating the potential for introduction of smallmouth bass as an additional control on the chubs. In some other western waters, bass and trout coexist, and bass seem to keep the chubs in check. In a high elevation water like Strawberry, bass growth will be very slow, so they may not become a major sportfish due to small size. Even small bass are voracious predators; and inhabit the shallows where the baby chubs are. However, there are some potential concerns with smallmouth. It is possible that bass spawning would not be successful at Strawberry due to the short growing season. Additionally, the bass may prey heavily on the small trout fingerlings that we stock in the weedbeds in the summer or enter the reservoir from the tributaries. We will evaluate all potential benefits and impacts before a proposal to stock bass is made. At that time, the proposal will be brought before the public for input before a final decision is made.

Voluntary Catch and release Will Keep The Fishing Good
     This should be a good year for fishing Strawberry. With a full reservoir and lower fish numbers than the past few years, the catch rate will probably be slower than it has been. But, the average fish size will be large, making 1998 the year to hook (and hopefully release) the trophy of a lifetime.
     Fish numbers may be down for the next couple of years. In 1995 and 1996, we estimated that there were over 600,000 adult Bear Lake cutthroat in the population. It isn't likely that we will see that density of trout again. This was a result of outstanding survival of fish we stocked the first few years following the rotenone treatment.
     There was no competition for food and little predation. Those Bear Lake cutts became predators themselves and ate up the majority of over 2 million small fingerlings that we stocked in the fall. The missing fingerlings would have reached the size that they would start being caught this year. The population now is large holdover fish, and survivors from our spring stocks of larger fish and wild trout which migrate out from the tributary streams. Our best estimates are that the population this year is in the range of 250,000 adults. That still amounts to almost 15 trout over 18 inches per acre. We are increasing our stocking of spring fish, and changing the stocking season of fingerlings to summer, when the large predators are mostly offshore. With this and recruitment from the streams, the numbers should bounce back in a couple of years.
     The current limit is four fish, of which only one trout may be over 18 inches. Further reducing harvest by voluntary catch and release will help protect the population and keep the fishing good throughout the season. We strongly urge the use of artificial lures and flies, which do not injure fish as badly as baited hooks. Handle the fish carefully, and return them to the water quickly. A good practice is to hold your breath when you take a fish out of the water. It reminds you to hurry!

New Tactics For Successful Fishing
     There will be a lot of water out there to cover this year. Strawberry is becoming much like Bear Lake in that there are vast areas of deep open water. The larger cutthroats are becoming nomadic, cruising the reservoir looking for prey. The remaining rainbows from the 1994 and 1995 stocks will move into newly flooded shoreline areas. Kokanee will school suspended at depth in the open water. Many of the traditional hotspots may not be productive. Some areas may be good during certain times of year and dead the rest of the time.
     The key to success this year will be to be mobile. Don't assume that an area is too deep or too shallow. The fish could be anywhere. They are not everywhere like they used to be. Whether from boats, shore, float tubes or pontoon craft, keep moving around until you locate fish. They do tend to travel in small schools, so you catch your fish in bunches. Fish finders are extremely useful to locate the area and depth oft he trout. Downriggers, lead weights and sinking flylines get your offering down to where they're at.
     Lures and flies that imitate small fish are becoming increasingly effective, as are frozen and salted minnows for bait. That banjo minnow lure that is advertised on late night cable might be just the ticket. Two other prey items that are becoming more important in the diet of Strawberry fish are worms (particularly in newly flooded areas) and crayfish. Night crawlers, rubber worm rigs or jigs, and red and brown leech flies tied sparse work well. Crawdad tails, and lures and flies that mimic crayfish are excellent in areas with rocky bottoms where the crawdads abound.
     I'm really getting the itch for the ice to pull away from shore at Strawberry so I can be the first one out in my float tube, casting after the big ones! But, thanks to el nino, its looking like a long wait. The snow is so deep the fences are buried. You can hardly tell where the land ends and the reservoir begins. There won't be open water until May. For now, it's time to browse through the catalogs, tie up some bugs, and get the gear in order.
     Happy fishing!