By Dan Potts
The first time I fished Willard Bay Reservoir was while I was still going to high school. At that time I had just received my driver's license, and I was off fishing any time I could come up with enough gas money for the old 1961 Ford Galaxy bomb.
The first thing that struck me about Willard was its immense size and the second was its shallow depth. This body of water is unique because it is shaped like a huge sewage treatment pond, with a relatively flat featureless bottom. A dike almost completely surrounds the reservoir.
I had heard there were a lot of largemouth bass, walleye, and channel cats to be had, although I knew little about catching warm-water fish at the time. I had grown up, like most Utahns, fishing for trout. But the first day I fished there I easily caught a limit of 10 largemouth bass on a red and white spoon. And I also caught my first walleye as a thunderstorm approached. And, so started my infatuation with warm-water fish and Willard Bay.
In the early '70s, Willard Bay had a large population of small largemouth bass, a nice population of large walleye and channel cats, and common carp – the primary prey species. By the late 70's the largemouths had all but disappeared, replaced by a thriving but stunted population of black crappie. The walleye were still doing well, although their average size had dropped some. The channel cats hung in there well, and of course, the carp persisted under 'predator-heavy' pressure.
By the early 80's the black crappie population had fallen off considerably and the average size of the walleye continued to fall. The channel catfish in Willard have always had the upper hand, due to their omnivorous (opportunistic) nature. Channels are typically caught on even, fast-moving artificial lures in Willard Bay, indicating that they are aggressive, versatile and efficient predators in this monotypic habitat. The carp continued to thrive under this heavy predatory pressure.
By the late 80's, 'the drought' had begun. The crappies were few but larger. The bluegill that were always present in limited numbers had secretly attained very large sizes, but were essentially unfished. The walleye were stunted and the channel cats and carp continued to hang in there.
The Utah Division of Wildlife Resources has made numerous attempts to add more forage fish species, including spotted shiners and pond smelt, among others, to cure the imbalance between predators and prey. Unfortunately, these previous attempts have not panned out to the DWR's expectations. Whether these introductions were poorly researched or simply unsuccessful because of the 'Gods' is not known.
By the early 90's the DWR decided to try again and introduced the highly controversial gizzard shad to provide another prey species to a predator-heavy system. The shad have survived the first few winters, and, their reproduction provided the stunted walleye with needed forage. The compensatory (makeup) growth of the walleye was impressive and even the channel cats responded well with increased condition factor (fatness). The crappie have also grown, but haven't responded with a large year class yet, although it seems inevitable. The large bluegill are not being caught by those who originally found them. An acquaintance did his Ph.D. dissertation on the interaction between gizzard shad and bluegill and found that gizzard shad indirectly out-competed the bluegill. So now what?
It is this fish ecologist's opinion that Willard Bay will always provide a fisheries that is either boom or bust. This washbasin-type reservoir fails to provide any significant structure or complexity to provide its fish species with needed refuge for their offspring This predator-heavy system relies on highly fecund (prolific) prey species to energize its highly efficient predators. Although carp are highly prolific, they also have extremely fast growth and quickly out grow their predator's ability to eat them. It is for this reason that gizzard shad were introduced. The shad's average ultimate size (less than 14") results in far slower growth, allowing a more efficient culling of intermediate sized individuals by larger predators like walleye and channel catfish. Young bluegill and crappie are quickly eaten up by the numerous predators in Willard Bay because they have few places to hide. Shad are schooling fish and hide in the vastness of their numbers. It is likely that, as Utah's long drought subsides and more undiked areas in Willard are reinundated, additional refuge for young-of-the year sunfish will be made available. This could result in a resurgence of stronger year classes of crappie and other centrarchids (sunfish).
The problem with gizzard shad, however, is that their continued existence in Willard is somewhat tenuous. Experts were unsure that they would be able to weather the winters here in Utah. It seems almost sure that we will ultimately have a winter that is harsh enough to wipe out enough shad in Willard Bay to leave the fishery without their benefit and throw things completely out of whack again. Of course, they can be reestablished, but probably not before a degree of instability again returns.
Under the new shad scenario, the walleye will undoubtedly move away from the structure of the dike to pursue their new forage – the nomadic shad. This will require new approaches to fishing for them. Long line trolling with shad-like imitations will probably become the summer time norm. Trolling in long sweeping 'S' curves will help to avoid spooking of fish as inside lines cut the corners and catch fish that have moved away from the noise of the boat. Willard Bay walleye, however, grow accustomed to boat traffic in the summer.
Another vogue approach is the use of planer boards to place baits away from the boat as they are trolled. The smaller in-line versions attach directly to heavy lines and larger rods to facilitate their use, and reduce the investment costs. When fish are caught, fishing buoys can be thrown out to mark the spot so that the area can be more thoroughly fished. It is assumed that schools of walleye will undoubtedly be herding schools of shad in this featureless washbasin.
It is also assumed that channel catfish will also pursue shad and continue their aggressive posture in Willard. Of course, one will be able to catch cats on the "typical baits," but trolling for cats can sometimes be more fun and productive with the added possibility of catching the other sportfishes.
The shad compete directly with black crappie in that they are filter feeders. Crappie have closely spaced gill rakers to enable them to strain the water for smaller organisms. Shad have even more closely spaced gill rakers, which means that they can eliminate virtually all of the microorganisms before they are large enough for the crappie to capture. This will probably displace the crappie ecologically. Crappie will be forced to feed upon shad and young carp, which are only available for about half of the year. But, they will grow well at that time and will be more catchable when the young fish are not available to them.
The DWR has planned to take yet another chance by introducing another predator into Willard Bay – the wiper. The wiper is a sterile hybrid cross between the striped bass and the white bass. Striped bass, as anyone who has fished for them in Lake Powell will tell you, are a large, fast growing shad-eater which fight well and are relatively easy to catch. In Utah, white bass are primarily found in Utah Lake where they bite almost anything that moves and some things that don't. They hit hard, and like stripers, fight well.
As you would suspect, wipers, or hybrids as they are sometimes called in other parts of the country, possess qualities about halfway between the two species. They strike hard and make striper-like runs until they tire. As tablefare they rate fair to good. The flesh is softer and more oily than that of walleye or crappies so anglers need to place more care on bleeding and quickly chilling them to preserve the quality. Wipers attain sizes of over eight pounds where there is adequate forage. Plus, their sterility allows the DWR to more easily fine tune the balance between wipers and other species including their prey, the gizzard shad, by only stocking appropriate numbers at appropriate times.
Wipers will surely out-compete walleye in open water areas, displacing them back to the dike and shoreline areas where they may be more easily caught. Walleye, under a 'wiper' scenario, will certainly not be as numerous but probably will not be greatly affected due to their ecological plasticity. Crappie will probably be less able to boom and bust and will likely grow well as previously stated. Shad would be so well cropped by so many efficient predators that adults would probably attain large sizes and spawn prolifically, flooding the system with young every summer to stimulate good growth in predators. Every fall as the young prey disappear, the sportfishes would again become easier to catch, as their expanded stomachs become empty. Catchability would reach a peak in late winter and spring prior to the influx of newly hatched fry.
On the other hand, will the DWR be able to track the situation at Willard and regularly provide the needed stock to establish the balance desired under their new monetary and administrative constraints? It has been suggested that their management of other hybrids like splake and tiger muskies has fallen short of expectations. These hybrids are not always stocked with regularity, which can lead to the boom and bust scenarios to which we are all too familiar. And, what if the shad do ultimately crash? Will we see the same problem we've had at Lake Powell – stunted and starving fish? Is adding yet another predator to an already predator-heavy system the answer?
Well, I certainly do not know the answers to these questions, but I know the past, and the future does not appear to be any different. Willard Bay will continue to be a changing, probably boom-and-bust fishery, that will always be good fishing for something – even if it is only carp and catfish! I like 'em!