Fat, healthy and growing fish in one year doesn't mean that those same fish will continue to grow the following year. When it does happen, fishermen enjoy it. But it is no certainty that fish will continue to grow and flourish year after year, especially in reservoirs.
North Dakota fishermen know the ups and downs of fish populations and growth rates in Lake Sakakawea very well. They also know it doesn't take long for a healthy reservoir, even one as large as Lake Sakakawea, to become an unproductive fishery. Good water levels and good water quality are key to a good fishery. Without those two elements, the fish in lakes, rivers and impoundments can get in trouble rather quickly.
In South Dakota fisheries, biologists know that Lake Oahe has changed so dramatically, and so quickly, that big changes are being proposed. During the high water days on the Missouri River in 2011, Lake Oahe flushed a large number of rainbow smelt through Oahe Dam. Because smelt are a key forage fish for walleye, and there's too few of them, Lake Oahe walleye growth has become stunted.
The solution, say biologists, is to up the walleye limit from four per day to eight. It may sound a bit odd to allow anglers to harvest more fish when a fishery is in trouble, but biologists believe that is preferred because extensive mortality is expected due to a minimal forage base. In other words, they are requesting that fishermen be allowed to catch more walleyes now while they still can.
"It's basically to provide that resource to anglers before those fish leave the system through mortality," says Geno Adams, fisheries program administrator for the South Dakota Department of Game, Fish and Parks.
There's another reason too. It takes little fish to make big fish. Fishermen are being asked to catch and keep more fish, which takes more predators out of the system. Fewer predators means a better opportunity for forage fish to stage a comeback. Bigger fish will follow. Lake Sakakawea experienced a similar situation just a few short years ago.
A few South Dakota fishing guides are questioning the proposal to increase daily walleye limits. They say it could hurt Lake Oahe's ability to produce trophy fish. What was learned on Lake Sakakawea when smelt numbers reached a low point a few years ago, was that fish became skinny and many of the larger fish, walleyes and northern pike, were believed to have died off. Indeed, fishermen reported very few catches of whopper walleyes or northern pike during the low smelt years.
North Dakota's portion of Lake Oahe has seen big changes in less than a year too. Lake Oahe was a thriving fishery a year ago, but has since slipped to the point where both the numbers and size of fish is dwindling. Numerous reports of skinny fish from Lake Oahe are being received, similar to what fishermen experienced on Lake Sakakawea a few short years ago.
The lesson to fishermen is, don't expect a growing resource one year to continue to do so the following year.
Another recent example I can cite is that four years ago the northern pike in Lake Darling were abundant and growing. I couldn't wait to fish them the following year, but that year turned out to be a disappointment. The pike weren't bigger and they seemed to be fewer in number. Then came the flood year of 2011 which scattered fish everywhere in the Souris River system and created water too murky to fish effectively.
2012 was a different story though. Fishing for northern pike at Lake Darling was excellent and the fish were fat and healthy. However, based on fishermen reports, the number of large walleye in Lake Darling was far fewer in 2012 than it had been in earlier years. Test netting confirmed that fishermen were correct in their assessment.
What will the spring of 2013 bring? Hopefully there is enough runoff to avoid a lowering of lake levels, which is always problematic for a fishery. Unfortunately, "wait until next year" is not often an effective fishing strategy.