Projects and Research

Fish Ladders -- Kids Fishing Day

Alaganik Angler Access Trail

Pipeline Lake 5 Stocking Program

Cutthroat Trout and Dolly Varden in Eyak and McKinley Lakes

Influence of fall-spawning salmon on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska

Up-coming Studies

Fish Ladders

Throughout Prince William Sound there are lakes and streams which fish are unable to access due to cascades or waterfalls. Fish ladders are designed to provide access to these areas to increase the available habitat and thus increase the number of wild fish.

The Cordova District built four fish ladders in the late 1970s and early '80s. Prior to building the ladders, we surveyed the streams above the barriers to measure the amount of spawning and rearing area and determine how many fish could be produced with the new habitat. Each year we check the ladders to see if they need repairs, and we count the number of adult fish that are using the ladders. Every year, thousands of sockeye, pink, and coho salmon use the ladders, increasing the number of fish available for anglers, the commercial fishery, subsistence harvest, and wildlife.

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Kids Fishing Day

Kids Fishing Day has become a popular annual event in Cordova. Kids of all ages come to learn about fishing and Making luresfish. The fisheries crew tries to emphasize not only the fun of fishing, but also the biology of salmon and other species found on the Copper River Delta. Activities like the life cycle game, pond ecology and lure making are a fun way to provide a combination of practical knowledge and biology.

Other agencies such as the U.S. Coast Guard and the Alaska Department of Fish and Game join in the fun to give the kids a well rounded day that includes boating safety and local sport fish regulations, along with catching fish, eating hot dogs and having fun.

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Alaganik Angler Access Trail Project

“Caring for the Land”

We worked cooperatively with the recreation crew to build the Alaganik Angler Access Trail. The trail is designed to improve sportfishing access and to protect the wetland vegetation from anglers walking across the fragile sphagnum bog. In the past, angler foot traffic created muddy trenches along the pathways up to a foot deep. Anglers would then walk around the trenches, destroying more vegetation and creating an ever-widening mudhole. An estimated one-half acre of wetland had been harmed, and it was expected that the damaged area would continue to increase without an improved, hardened trail.

Working cooperatively with the recreation crew, loading bridge materials

Loading bridge materials

Happy anglers using the new Geoblock trail

Happy anglers using the new Geoblock® trail

Perhaps the most important aspect is that the natural beauty of the area will be restored to a large degree. Although the trail itself isn’t natural, the Geoblock® used for the first part of the trail is level with the ground and will allow vegetation to grow through it, minimizing its visibility. The Geoblock® distributes the weight over a larger area, and the roots of the vegetation hold the soil together so new mudholes do not form.

Moose seem to like the trail too!

Moose seem to like the trail too!

Notice the vegetation growing through the Geoblock

Notice the vegetation growing through the
Geoblock® one year after installation.

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Pipeline Lake 5 Stocking Program

We began a 5-year cutthroat trout stocking project on Pipeline Lake 5 during the 2001 summer field season. The stocking was initiated in order to enhance recreational angling opportunities in the Pipeline Lakes complex, which consists of four other lakes. In recent years Cordova Ranger District fisheries personnel have been concerned about an apparent decline in cutthroat trout populations in the other lakes. Pipeline Lake 5, a formerly fishless lake, has less aquatic vegetation, good over-wintering conditions, and has quality spawning habitat in the inlet stream. Therefore, we felt there was a good chance for establishing a self-sustaining cutthroat trout population.

A juvenile cutthroat trout to be introduced into Pipeline Lake 5

We also feel there is an excellent opportunity to gather valuable information on cutthroat trout growth and population dynamics in these upland muskeg lakes. This information may provide insight into the problems with the cutthroat trout populations in the other Pipeline Lakes. A better understanding of these populations would aid in the overall management of the recreational cutthroat trout fishery on the District.

Wild cutthroat are captured with minnow traps in the nearby McKinley Lake, the other Pipeline lakes, and their outlet streams. The fish are then transported to Pipeline Lake 5. Each fish is individually marked with a small PIT tag. This allows us to monitor individual growth and population dynamics using mark-and-recapture population estimates. We will also be able to collect additional information on survival and recruitment. Fish scale analysis will help to verify the age structure of the introduced fish and the population in the lake.

Sexually mature cutthroat trout captured in Pipeline Lake 5

Although no spawners were observed during the spring spawning survey, in the fall we were ecstatic to find cutthroat trout fry in the inlet stream. We now have evidence the introduced fish are successfully reproducing. Measurements of recaptured fish show very rapid growth as well.

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Population Structure and Distribution of Coastal Cutthroat Trout and Dolly Varden in Eyak and McKinley Lakes

What effect does increased sport fishing pressure have on Dolly Varden and cutthroat trout populations? What are the incidental mortalities of Dolly Varden and cutthroat trout in the whitefish subsistence fishery? These questions are impossible to determine without baseline data on current fish populations.

The objectives of this project are to:

  1. Develop reliable sampling protocols to estimate the seasonal abundance of coastal cutthroat trout and Dolly Varden char populations in Eyak and McKinley lakes;

  2. Determine stock composition, through life history identification, of cutthroat and Dolly Varden populations;

  3. Determine age and growth characteristics of cutthroat and Dolly Varden populations.

A whitefish from the depths of McKinley Lake

This information will help managers answer general questions about population trends and habitat relationships of Dolly Varden and cutthroat trout across Forest lands, as well as provide baseline data towards answering specific questions concerning subsistence fisheries in Eyak and McKinley lakes.

To capture fish we used monofilament gill nets. The nets used are similar to those used in the whitefish subsistence fishery. In addition to being an efficient means of sampling large lakes, these nets allowed us to estimate the incidental catch of Dolly Varden and cutthroat trout in the subsistence fishery. Floy tags serve as the identifying mark for capture-recapture estimates and will provide information on seasonal growth and movement patterns of fish recaptured at later sampling dates.

Hauling in the gillnet

To our surprise, whitefish was the predominant species caught in McKinley Lake, whereas in Eyak Lake, only one whitefish was caught. Migration patterns of whitefish in this area are not known, so it is possible whitefish were not in Eyak Lake during our sampling periods, but are there at other times. In the future, the use of radio tags could determine spawning locations and whether seasonal migrations occur.

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Influence of Fall-Spawning Salmon on Growth and Production of Juvenile Coho Salmon Rearing in Beaver Ponds on the Copper River Delta, Alaska - A Thesis by Dirk W. Lang

Spawning Coho

This thesis examined the influence of fall-spawning coho salmon on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska. During the fall of 1999 and 2000 fish rearing in ponds that received spawning salmon were compared to ponds that did not receive spawners, and to ponds that were artificially enriched with salmon carcasses and eggs. Juvenile coho salmon responded variably to fall-spawning salmon. There were no consistent patterns associated with the two naturally occurring pond types (spawning vs no spawning). In some ponds, fall-spawning salmon increased growth rates and improved the body condition of juvenile coho salmon. Enrichment with salmon carcasses and eggs significantly increased growth rates of fish in non-spawning ponds. For some ponds, the relative influence of spawning and enrichment on body condition depended on fish size. There was no evidence that the influence of fall-spawning resulted in greater smolt production. Fall-spawning salmon provide important food resources that can benefit juvenile coho salmon rearing in beaver ponds on the Copper River Delta. However, other factors such as nutrients from riparian vegetation and catchment characteristics that control hydrology and thermal regimes are important to coho salmon smolt production.

A complete pdf version of the thesis...1.8mb

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Up-coming Studies

Mile 18 Fall Smolt Outmigration

The Mile 18 Creek system on the Copper River Delta has been extensively studied by Forest Service scientists and the Cordova Ranger District. Projects include seven years of smolt outmigration data, eight years of adult escapement data, habitat surveys with smolt production estimates, and a study of the influence of adult salmon carcasses on juvenile coho salmon growth rates. While the projects have enabled us to answer many questions about the available habitat and fish production, they have also raised new questions.

PIT tagging juvenile coho salmon was a large part of the salmon carcass/juvenile growth rate study. One of the interesting side notes was that a portion of juvenile coho tagged in the fall were not recaptured in their ponds during later trapping efforts or recaptured at a weir during the normal spring smolt outmigration. These fish ranged in size from 80 to 90 mm and had typical smolt characteristics such as silver coloration and fading parr marks. The ponds where these fish were trapped and marked were in the lower portion of the system.

Coho SmoltThis raises the question of whether there is a fall outmigration of coho smolts in the Mile 18 system in addition to the normal outmigration in the spring. In one Russian stream, coho smolt have been documented migrating as late as October, but that appears to be the tail end of a single late run. Instances of two separate smolt migrations have not been documented. We also have no idea of what percentage of the smolt population may be leaving in the fall as compared to the spring.

A rotary screw fish trap will be used to capture outmigrating smolts in both the spring and fall. To determine if smolts are migrating to the ocean or simply overwintering in the estuaries, the movement of the fall fish will be tracked with radio tags. Radio transmitters will be surgically implanted in the abdomens of 30 smolts. Tracking of smolts will be conducted by foot, boat, and fixed wing plane.

The migration behavior of these fish has several implications for land managers. Generally, the availability of winter habitat limits coho smolt production in Alaska streams. If the coho are simply spending the winter in the fresh water areas of the estuary, the migration may be due to the need for additional winter habitat in the Mile 18 Creek system. Winter habitat enhancement projects could increase production. If instead they are truly undergoing the changes for salt water life, there may be a need to re-think habitat enhancement efforts. In addition, if a large percentage of the smolts are fall migrants, we may have grossly underestimated the productivity of the system using our past spring smolt numbers and the generally accepted coho salmon production models.

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Key Contacts

Chugach National Forest
161 East 1st Avenue, Door #8
Anchorage, Alaska 99503
907-743-9500

Glacier Ranger District
P.O. Box 129
Forest Station Road
Girdwood, AK 99587
(907) 783-3242

Cordova Ranger District
P.O.Box 280,
Cordova, AK 99574
(907) 424-7661

Seward Ranger District
33599 Ranger Station Spur
Mile marker 23.5
Seward, AK 99664
(907) 288-3178



https://www.fs.usda.gov/detail/chugach/about-forest/districts/?cid=stelprdb5052473