Anglers at Diamond Lake this year will feel like they’ve hit the jackpot.

To prepare the lake for its dose of rotenone in September, which will poison the non-native tui chub that have taken over the lake, Oregon Department of Fish and Wildlife officials have changed the rules of trout fishing in Diamond Lake for the spring and summer seasons.

Dave Loomis, watershed district manager for the Umpqua District of Oregon Fish and Wildlife, said the previous catch limit at Diamond Lake was five fish, with a total daily possession of 10. Of those, the minimum length was eight inches, and each angler could only keep one fish with a length of more than 20 inches.

This year, though, the limits have gone up – way up.

Anglers at Diamond Lake could leave after one day of fishing with as many as 20 fish, with no size limits attached.

As soon as the ice starts breaking up on the surface, which Loomis hopes will be mid-May, the Oregon Department of Fish and Wildlife will release about 20,000 hatchery trout, none smaller than 8 inches, into the lake to be fished along with the rest. Loomis said the department spends about $1.50 per fish to stock the lake.

Another 4,000 trout will be released prior to Free Fishing Weekend on June 10 and 11. Loomis thinks that there will be a total of about 40,000 catchable fish in the lake this year.

In past years, Loomis said as many as 40,000 to 50,000 catchable-sized hatchery trout were released into the lake for fishing.

”We felt it was prudent to put about 24,000 in this year,” he said.

The Oregon Department of Fish and Wildlife and other federal, state and local agencies plan to rid the lake of the chub in September, which should have an impact on the blue-green algae that is also taking over the lake.

Although these issues have been on the radar of the Department of Fish and Wildlife for more than a decade, years of research, controversy and legal battles with environmental organizations concerning the use of rotenone have continually came up as road blocks.

The decision on how to fix the problem was to close Diamond Lake from Sept. 5 to Oct. 31 and dump rotenone into the lake.

Rotenone is a plant material that is native to areas like South America and New Zealand and is toxic to fish. According to Loomis, rotenone can also be used as an insecticide or pesticide for some plants.

When put in the lake, the chemical prevents oxygen from changing molecularly so that it can be used by fish, ”effectively killing anything with gills,” Loomis said. He said the chemical has a very quick half-life, which means it will dissipate quickly from the lake.

Allowing people to fish the lake so much this year is largely serving two purposes. The first is to get anglers to catch as many trout as possible. The other, Loomis said, is to assure that the economy in the area remains strong throughout the season so that when the lake is closed in September, it will not have too large of an economic impact.

Letting people fish so freely is also one of the ways that the lake is being prepared for the rotenone dump. If the chemical were dumped now, millions of fish would die. If they all began to decompose in the lake it would overload it with nutrients that could impact its oxygen levels.

He said what makes the chub, a non-native species to Diamond Lake, such a hassle is that they eat the lake’s supply of zooplankton, an important lake habitat food source for trout and other native lake species. The zooplankton is also responsible for eating the blue-green algae.

Large chubs only get to a length of about seven inches, but a mature chub can lay more than 35,000 eggs.

According to the Oregon Department of Fish and Wildlife’s Web site, tui chub are in the same food chain as trout, and because of their rapid rate of procreation can take over a lake in a small period of time, eliminating the trout’s resources.

The blue-green algae that is taking over Diamond Lake can be toxic, and has caused the lake to be closed to swimmers in recent summers. According to the Oregon Department of Human Services Web site, the algae is not toxic in small amounts. Under the right conditions, though, it can grow rapidly.

When the blooms grow too large, they create a neurotoxin that poses health hazards to humans and animals.

According to the Diamond Lake Restoration Project documents, the blue-green algae in Diamond Lake stayed in check until 2001. That’s when severe blooms began appearing, and according to the statement, this could be directly related to the influx of the tui chub.

Before those problems can be fixed, the Umpqua District of Oregon Fish and Wildlife has to lower the lake level by eight feet so the lake water doesn’t go in to surrounding streams when the rotenone treatment occurs. Deep canals dug in the 1950s can control water flowing in and out of the lake. Loomis said the hatches for the in-flow canal have been closed since September, and the lake is currently seven feet down from normal.

This will be noticeable for those needing boat ramps, as the water will be too low for them to be of use. Those who fish along the edge will also notice a difference, but Loomis said the lake will retain roughly 80 percent of its surface area.

After anglers have had a couple of months to fish Diamond Lake, a contracted fisherman and his crew will come from Newport to net fish in the lake. Loomis said the fishermen will use several different kinds of nets, such as gill nets and trap nets, and fish the lake day and night on weekdays from July 17 to Aug. 11.

Once caught, Loomis said there are a few different options the fisherman could pursue with all the fish. He said they could be used for fish fertilizer, emulsion fertilizer and fish feed.

A total of 180,000 pounds of rotenone powder will be dumped into the lake in one day, along with 9,000 gallons of a liquid form of rotenone. The total cost for the rotenone was $850,000. Only about 5 percent of that is active rotenone, Loomis said, which is why such a large amount is necessary to get the job done.

Once the rotenone has been dumped, initially many of the chub and remaining trout that are killed will float to the surface of the water. Loomis said at this point someone will skim the dead fish off the surface.

He said right now there could be close to 100 tons of fish in the lake, and that the goal is to leave less than half of those to decompose on the lake floor.

Sherri Chambers, a wildlife biologist for the North Umpqua Ranger District of the U.S. Forest Service, was the project leader for the Diamond Lake interdisciplinary team that looked into different solutions. She said other options ranged from taking no action, to hiring people to net fish the lake extensively for six consecutive years, to using a rotenone treatment but with a different strategy for stocking the fish.

In the end, though, allowing anglers to fish out the lake themselves before rotenone treatment was the best way, since it also helps the local economy, Loomis said.

Although the chub population has been increasing for more than a decade, it was the presence of the toxic algae blooms that finally made it imperative that something be done.

”The problems up at the lake just became too serious to let it go, and even though using rotenone is a serious solution, just letting the lake go ahead and further deteriorate ecologically wasn’t acceptable either,” Chambers said.

When a chub overpopulation occurred in Diamond Lake in the 1940s and 1950s, rotenone was the method used to rid the water of them. It wasn’t until 1992 that tui chub were again spotted in Diamond Lake.

Loomis suspects they ended up there when anglers used them for live bait, possibly letting some get away in the process. It’s against Oregon state angling regulations to use non-native species as live bait throughout most of Oregon, as a result of the tui chub problems from the 1940s and 1950s.

Lodging facilities in the area are eagerly awaiting the this summer season. Rick Rockholt, marketing coordinator for Diamond Lake Resort, said with the looser limits on fishing, they’re expecting to have a great spring and summer season. Losing the last two months in September and October will hurt, he said, but it’s something they’ve known about for awhile and have been able to plan for.

Although fishing in Diamond Lake this summer may seem like a free-for-all, the Oregon Department of Fish and Wildlife would like to remind people that a permit is still needed to fish the lake.