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spectr17
10-30-2002, 12:11 AM
Lees Ferry Regulations Modified For 2003

AZ G&FD

10/22/02

PHOENIX – If you plan to fish for trout at the renowned Lees Ferry in northern Arizona in 2003, there have been some regulation changes that will allow you to improve the health of this world-class fishery by harvesting more non-trophy sized rainbow trout.

The Arizona Game and Fish Commission on Oct. 19 adopted a variety of fishing regulation changes for the 2003 year, including modifications to the special regulations at this classic tail-water fishery tucked between Lake Powell and the Grand Canyon.

Fisheries Chief Larry Riley told the Game and Fish Commission that any regulation change at this world-renowned fishery at the river entrance to the Grand Canyon is by its very nature a source of controversy – a lot of different factions have strong ideas and philosophies when it comes to the fishery, and the adjacent Grand Canyon river ecosystem.

Despite all those varying opinions, there were no voices raised at the commission meeting in opposition to the proposal to increase the harvest of smaller trout to allow for better grow outs of trophy fish.

The fishing regulation changes adopted for Lees Ferry starting in 2003 include:

· Increasing the bag limit and reducing the maximum size limit for trout. From the Colorado River from the Glen Canyon Dam to the upstream end of the Paria riffle, trout over 12 inches can’t be possessed starting Jan. 1, 2003. The daily bag limit will be four trout per day and eight trout total in possession. Trout taken from this area shall be killed immediately and retained as part of the bag limit, or immediately released. Current regulations for this reach of river are a 16-inch maximum size with two trout per day and a four-trout total possession limit.

· The special regulation boundary for the Lees Ferry “Blue Ribbon” trout fishery has been moved from the Marble Canyon Bridge upstream to the upstream end of the Paria riffle.

Fisheries Chief Larry Riley explained that the blue ribbon rainbow trout fishery known as Lees Ferry on the Colorado River has long been a controversial fishery due to river flows, native fish concerns, and variable quality of the fishery.

In the late 1970s and early 1980s, mean fish size was above 400mm, but now mean fish size is below 300mm. Fisheries management of Lees Ferry has evolved from a put-and-take strategy in the 1970s to current regulatory programs that are more consistent with “blue ribbon” fishery concepts (i.e., restrictions on harvest, maximum size limit and allowance of only barbless artificial lures and flies).

Riley said that most management schemes implemented thus far have been aimed at producing quality angling experience, such as preserving high standing stocks of healthy, catchable, wild-spawned fish with restrictions on take of “trophy” sized fish.

“However, high levels of natural reproduction, survival of fry and subsequent abundance of adult fish associated with stabilized flows in the 1990s have led to increasing numbers of trout, declining fish growth rates, a surplus of small fish less than 12 inches long, and diminished body condition. These problems have been especially pronounced during recent years when dam discharge and subsequent fish habitat and food quantities have declined,” Riley told the commission.

Given the preponderance of small fish currently in the system, the changes were needed to provide some new recreational harvest opportunities that have not existed at Lees Ferry for some time and to help alleviate problems stemming from high trout densities.

The Glen Canyon Dam Adaptive Management Program developed by multiple agencies including the department, has set trout objectives for the Colorado River stretch from Glen Canyon Dam to the Paria River. These objectives include maintaining and managing rainbow trout numbers for 100,000 age II+ fish.

“Since 1994, electro-fishing data has shown a dramatic increase in rainbow trout density. Electro-fishing data has also shown that since 1993, rainbow trout densities have reached and/or exceeded the amount of available habitat as reflected by mean annual stream flow,” Riley said.

In 2000 the Lees Ferry rainbow trout population was estimated at 256,000 age II+ fish, suggesting the population had more than doubled since the early 1990s.

As is typical with dense populations of trout, the data shows that since 1994 both condition factor (relative plumpness of fish) and proportional stock density (the proportion of fish 16 inches and larger within the population have steadily decreased.

“Too many fish means smaller fish, and larger fish are sometimes in poor condition. Furthermore, data on growth rates of wild fish from recent years indicate that fish growth rates have been declining since fish densities reached a peak in 1997-1998,” Riley pointed out.

Compounding the issue of high density and very successful recruitment was a reduction in discharges during recent years. Due to low inflow to Lake Powell daily minimum flows dropped to 5,000 cubic feet per second (cfs) on several occasions during 2001, as provided for in the Record of Decision. There is a likelihood that such flows negatively impacted productivity of the trout food base, thus reducing the available food supplies.

“Trout densities need to be reduced in order to increase growth, average fish size, and improve the overall quality of the fishery. With an abundance of small trout and PSD steadily decreasing, there is a unique opportunity to provide greater harvest while possibly improving the fishery,” he explained.

While maximum size limits typically reduce harvest, the suggested increased bag/possession limits will allow greater harvest of small rainbow trout, which are thought to form the “bottleneck” in growth to larger sizes. Fish below 12 inches are not considered desirable by many Lees Ferry anglers, so risks of compromising the quality of the fishery (as it stands right now) through over harvest are small.

Additionally, the increase in bag/possession limits may attract some new recreational users to the Lees Ferry fishery, thus further increasing harvest of trout, specifically trout not desired by the traditional Lees Ferry angler.

“Therefore, we will now be providing local residents a legal recreational experience they desire -- increased bag limit and bait fishing -- while managing for native humpback chub, which is reducing trout densities,” Riley said.