The Division of Wildlife Resources is aware that some anglers are unhappy with fishery management at Joe's Valley Reservoir. The real problem stems from the abundance of chubs at the reservoir and attempts by the DWR to combat the problems created by this unwanted species. The management strategy in recent years has resulted in restrictive regulations and changes in the kinds and numbers of fish that are stocked.
The problem had its beginning with the illegal practice of using live fish as bait. For years, law-breakers have captured and kept juvenile chubs in live wells for use as bait. Introduction of any kind of minnows to a reservoir creates management mayhem. In the course of a fishing trip, some baitfish get off the hook. At the end of a day, law-breakers dump leftover chubs overboard to avoid a citation and fine. The minnows (juvenile chubs) grow up and reproduce. In the case of Joe's Valley, the illegal baitfish grew to outnumber and out-compete the desirable sportfish.
From that time forward, the DWR has been fighting a war of fish supremacy. Chubs eat the same food and occupy the same habitat as trout. Unfortunately, just like weeds in a garden, chubs are incredible invaders and took over. After a while, the trout stocked by the DWR failed to grow, and weren't showing up in creel surveys. Continued planting of the same trout became fruitless. The DWR had to do something different. A new strategy was developed, using splake as the dominant predator.
Splake are a sterile hybrid between brook and lake trout. Because males and females don't waste energy on reproductive products, all energy goes into growth. Furthermore, because they can't reproduce, they can't overpopulate a reservoir and stunt. Regulated stocking keeps the population at a manageable level. Another important attribute is the fishes' predatory nature. Once a splake reaches a size of 16 inches or so, they become chub predators, which is exactly what's needed to manage the chub problem.
Many anglers wonder why the DWR doesn't poison the fishery and start over. "I would love to treat Joe's Valley Reservoir," says Paul Birdsey, Regional Aquatics Manager. "When I came to the region more than a year ago, that's exactly what I had in mind. However, once I started planning the technical aspects of the treatment, I discovered that it just wouldn't work."
First of all, the reservoir's outflow is about 300 cubic feet per second, because of downstream water demands, which include culinary, agricultural and industrial uses. For a treatment to be successful, the outflow must be slowed to a minimum, so that a high concentration of rotenone can be held in the reservoir and to give the downstream detoxification process a chance to work. Culinary water may have to be shut down for as long as two weeks. Farmers would have to forgo water for irrigation and stock watering. The Hunter Power Plant wouldn't have the supply it needed for continued operation.
There's an equally serious technical problem. The toxin, rotenone, doesn't work well in cold water. That's a problem at Joe's Valley, especially because it drops 100 feet in places. Deep water is very cold. Rotenone causes a chemical reaction that prevents the gills of a fish from absorbing oxygen from the water. The reaction doesn't predictably occur in cold water. During the stress of treatment, fish naturally escape to deeper water, where oxygen levels are higher. In Joes Valley, the target fish would retreat to the cold depths to avoid suffocation.
Paul Birdsey is very concerned that he could spend millions of sportsmen's dollars on a project, which almost certainly would fail. There's another problem, relative to the reservoir's depth. Even if the toxin worked effectively in cold water, the current application equipment and technology is not suited for distributing the chemical in much more than about 30 feet of water. There's no way to assure complete coverage and uniform application, leaving the target fish another avenue of escape.
If user conflicts and technical roadblocks aren't enough, the DWR faces endangered species issues. Joe's Valley Reservoir is home to the bluehead sucker, a species that occupies the highest tier of state protection. Because rotenone poisons all fish, this population would have to be sacrificed. This could push the species toward federal listing as threatened or endangered. If this were to happen, the Endangered Species Act requires that the federal government take over management for the protection of the species. Such management could jeopardize sportfishing altogether.
Since treatment with rotenone is not possible, what else can be done? In 2006, the DWR began netting and removing chubs from the reservoir. During the past two years, this was done just prior to the spawning period. To date, 27,000 pounds of chubs have been netted and removed from Joe's Valley. Besides the fish themselves, the DWR estimates that by removing the gravid females, as many as 5 million eggs were destroyed. That has to make an impact.
In order to provide anglers with an alternate trout species, the DWR has begun stocking tiger trout, another sterile hybrid. Like splake, tiger trout can't reproduce, so there's no chance for over-population and stunting. All energy goes into growth, and tigers grow up to be chub-munching machines. Paul Birdsey expects that the chub population will plummet within five years. At such time, restrictive regulations and slot limits can be eliminated. "In a few short years, Joe's Valley Reservoir will be a great trophy and family fishery by anyone's standards." says Birdsey. "We just need some time for the plan to work."