Roosevelt Lake On The Line

Can monster bass save vital fishery?

Arizona Game and Fish will introduce Florida strain bass in hopes they can gobble up the invading gizzard shad.

Arizona Game and Fish will introduce Florida strain bass in hopes they can gobble up the invading gizzard shad. Photo by Pete Aleshire. |

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Move over little bass — the big bass is moving in.

At least, that’s the song advocates for the beleaguered Roosevelt Lake bass fishery hope they’ll be singing later this year.

The Arizona Game and Fish Commission has decided to spend $356,000 to reverse an alarming decline in the bass populations in the lake by introducing fast-growing Florida strain bass, conducting ongoing research and scattering artificial reefs to help the bass get enough to eat.

The state will spend the money in the course of the next two years, including an initial $100,000 to stock Florida strain bass, $120,000 to create fish habitat, $40,000 for additional research and $35,000 in Game and Fish personnel costs.

The state will also investigate turning a warm-water fish hatchery into a breeding facility for Florida strain bass, to reduce the long-term task of growing bass for introduction into reservoirs on the Salt River in response to a series of challenges, including the invasion of gizzard shad.

Experts think the bigger bass may not only delight anglers, but introduce predators that can take advantage of the invasion of gizzard shad — which grow too large for the northern strain largemouth bass that currently inhabit the lake.

“Florida strain bass have a very high growth rate — they get very large, very quick,” said Chris Cantrell, head of the fishery branch for the Arizona Game and Fish Department. “Some Eastern states have had very good success in stocking Florida strain bass — and the angler can catch a bigger fish. I don’t know if it will be the magic bullet for the gizzard shad.”

Game and Fish electro-shocking, fish-sampling surveys indicate that the number of Northern strain largemouth bass, bluegill and black crappie have all declined from 76 to 85 percent — with average weights also dropping about 10 percent.

In 2008 the electric shocks produced 44 bass per hour, but in 2013 the total had dropped to 11 fish per hour.

The number of complaints about low catch rates has also risen sharply in a lake once ranked as one of the top bass fisheries in the country.

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Gizzard shad

James Goughnour, a local fishing expert who has spearheaded efforts to bolster the fishery, hailed the Game and Fish plans. “There is still a lot of work to do related to the gizzard shad problem and it’s going to take years to get Roosevelt Lake back to its glory days. Restocking, more habitat and raising lake water levels, hopefully will balance the gizzard shad invasion.”

The plunging catch rates for bass and crappie have dealt a blow to hotels, marinas, businesses and everyone else who depends on spending by eager fishermen.

A single, nationally televised bass tournament can inject some $600,000 into the local economy in the course of a weekend.

A study by Arizona State University done for the state estimated the economic impact of trips taken by the state’s 255,000 anglers at nearly $1 billion annually.

Cantrell said the lake has been battered by a perfect storm of changes that have allowed the invasive gizzard shad to thrive, while apparently dramatically reducing populations of threadfin shad, all critical to the health of the populations of largemouth bass and crappie. Those sportfish and bluegill also consume plankton when they’re tiny, as well as crayfish, insects, snails and other prey. The bass also feed on the smaller fish like bluegill and crappie.

One major factor was the unexpected arrival of the gizzard shad, which gobble up the same plankton and algae that sustain the threadfin shad — long the base of the food chain for the sport fishery. The threadfin shad top out at about six or eight inches in size, perfect forage for the northern strain of largemouth bass. However, the gizzard shad grow to 12 or 16 inches, too big for the northern strain bass to swallow — since a bass can only swallow and digest a fish about half its size.

In addition, lake levels have dropped sharply. Three years ago, the lake reached record levels, inundating brush along the shoreline, producing nutrients resulting in bumper crops of fish like shad and bluegill. The submerged brush also created perfect conditions for the largemouth bass, which are ambush predators. However, the return of the drought has half-emptied the reservoir, leaving barren shorelines and providing far less nutrients or places for the bass to lay their traps.

In addition, a virus that affects largemouth bass has thinned the population, said Cantrell.

Finally, the lake has suffered several recent outbreaks of golden algae, which at certain concentrations releases a toxin fatal to fish. Last summer the growth caused a major fish kill in the Salt River and later less serious die offs in the reservoir. Turns out, most of the fish that turned up dead were gizzard shad — but that’s because they’ve become more numerous than any other fish in the lake.

The Game and Fish Department will likely convert a warm-water hatchery at Bubbling Pond near Cornville on the Verde River.

Cantrell said that stocking Florida strain bass into the lake would likely reduce the number of bass the average angler catches, but produce far more monster fish. For northern strain bass, a big fish tops the scale at five or six pounds. But Florida strain bass routinely top 10 pounds — and can grow to such formidable sizes in as little as five years, depending on forage and water temperatures.

Cantrell said Game and Fish stocked Apache Lake and Saguaro Lake with Florida strain bass between 2007 and 2009 after a golden algae bloom laid waste to the fishery. The Florida strain bass have done well there, although they’ve apparently interbred with the northern strain bass also in the lake. Cantrell said one angler at a recent tournament on Apache Lake pulled out a nine-pound bass.

“That’s pretty awesome,” he said. “The bag limits are a whole lot better up there” since the new strain of bass was introduced.

Cantrell noted that northern strain bass can get huge, but it takes them roughly twice as long. “Northern strain have the ability to get to 12 pounds or more and Canyon Lake has the state record of 16 pounds, which is thought to be a northern strain. But the Florida strain have much faster growth rates and can get to six inches in one year, so you’ve got a really good opportunity to grow a fishery.”

He noted that many anglers consider the Florida strain bass more wary and harder to catch — and perhaps more likely to avoid lures altogether after a near-catch experience. They’re also more expensive for Game and Fish to buy as fingerlings for stocking, which is one reason the state may start its own bass hatchery.

However, the Florida strain bass will almost certainly do much better when it comes to hunting gizzard shad.

“The bass will try to eat fish up to half their length in size. So a 16-inch-long bass can eat an eight-inch-long gizzard shad. But you need a 30- or 31-inch bass to eat a 15-inch gizzard shad.”

The gizzard shad have also invaded Lake Powell, with dramatic effects on the fishery there. They seem to have displaced the threadfin shad as well as other algae eaters like carp. However, the major predator fish in Lake Powell is the striped bass, which grows much larger than the largemouth bass, and that means they can continue to prey on the gizzard shad.

However, Cantrell said Game and Fish isn’t considering introducing stripers into Roosevelt Lake, since they tend to quickly dominate any lake they’re in.

“I think that the intent of the management of Roosevelt Lake is for largemouth bass. I don’t think we want to introduce another apex predator. We’re on the verge of being able to commit to stocking the Florida strain. Long term, that’s where we want to go. I really hope we can get Roosevelt back to the heyday it was at.”

A release issued this week by Game and Fish noted that the state has already shifted manpower toward the project, began to design the fish habitat, drafted a habitat management plan and finished necessary environmental reviews.

Game and Fish has also set up a fund to take donations to match the first $50,000 set aside to pay for stocking the larger strain of bass.

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