"The higher level, though, is a double-edge sword. The aquatic weeds we have now will go away without the sunlight. But there will be more sandy coves that will be flooded to grow weeds," said Gustaveson.

"Every year is different. There are variations that happen every year and it's incredible to watch."

Predictions are that the lake will come up about 50 feet this spring. Heavy runoffs like this bring down nutrients, which lead to increased production of both shad and game fish. It also means that inflow areas near the Colorado and San Juan rivers will be especially productive for anglers.

The spike flood, where water was released from the dam to flood the Colorado River back in March, also helped. It forced some sediments out of the back of the canyons, which resulted in more plankton being released into the lake. This benefited striped bass and will benefit the upcoming crop of shad, which means there may well be a good shad population in the lake this year.

The largemouth bass population is strong this year, but Gustaveson said it is at the "top of the peak."

Without shad, the smaller bluegill, sunfish and young bass were hit hard by predators, "so we have the big largemouth and crappie this year, but the younger fish that we count on for the future are gone. We're missing a year class. They were consumed by predators. We won't see the loss this year, but we will in the future."

The one wildcard in this delicate balance is the rise of the gizzard shad. These larger shad were mistakenly placed in a lake upstream from Lake Powell several years ago. They made it downstream and are now fairly abundant throughout the lake.

"We now have a tremendous population of big adults that are so big no predator can handle them. Some are upwards of 18 inches and I've seen some up to 3 to 5 pounds. They are big egg tankers and when they spawn, the young will help supplement the threadfin shad," he said.

Since the young of both shad species are identical at birth, it will be a couple of months after the spawn before biologists can measure the impact of the gizzard shad.

One of the main hotspots for striper fishing right now is an area near the dam. In the spring, when the water starts to warm, spawning behavior draws the fish to current. They follow the flow of water to the dam, hit the dead end and stay. Anglers are reporting catching upwards of 50 to 75 fish a day.

As for where to fish, Gustaveson said that because the striped bass don't have to school to round up shad this year and can find plankton spread throughout the lake, the fish are scattered lakewide in the upper layers or in water between 6 and 20 feet below the surface.

"Which means the best way to fish is by trolling. And, if you find fish, then you can stop and cast a jig or throw bait," he said.