Lake information report

Name: Trout

Nearest Town: Coleraine Primary County: Itasca Survey Date: 08/16/2010 Inventory Number: 31021600

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Public Access Information

Fishing Regulations:

Lake Characteristics

Fish Sampled for the 2010 Survey Year

Length of Selected Species (Trapnet, Gillnet) Sampled for the 2010 Survey Year

Fish Stocking Activity

Fish Stocked by Species for the Last Ten Years

Fish Consumption Guidelines

These fish consumption guidelines help people make choices about which fish to eat and how often. Following the guidelin es enables people to reduce their exposure to contaminants while still enjoying the many benefits from fish.

Pregnant Women, Women who may become pregnant and Children under age 15

General Population

DOWID - MN DNR, Divion of Waters' lake ID number.

Contaminants listed were measured at levels that trigger advice to limit consumption.

Listing of consumption guidelines do not imply the fish are legal to keep, MN DNR fishing regulations should be consulted.

Dioxin
Mercury
PCBS - Polychlorinated biphenyls
PFOS - Perfluorooctane sulfanate

Status of the Fishery (as of 08/16/2010)

Trout Lake is a large, fertile, class 22 lake located immediately south of Coleraine, Minnesota. As a result of industrial and municipal practices within the watershed, the lake has experienced tremendous changes in water quality and the fish community. In recent years, the lake has provided a quality northern pike and walleye fishery. The 2008 lake management plan indicates walleye and northern pike as the primary species of management with black crappie, largemouth bass and smallmouth bass as secondary species. In 2005, a 17 to 26 inch protected slot length limit with only one fish over 26 inches in possession was implemented for walleye. The 2010 assessment also included additional sampling of near shore fish species in order to calculate an Index of Biotic Integrity (IBI) score.

The 2008 management plan indicates the goal for walleye is to maintain a gill net catch of 10 fish/net with 30-60% over 15 inches and 10-30% over 20 inches. The walleye catch was 9.9 fish/gill net in 2007 but declined to 5.3 fish/net in 2010. The catch was within the normal range for the lake class. The sampled fish ranged from 10.8 to 21.8 inches and averaged 16.1 inches. The size distribution met the size structure goals, having 48% of the fish over 15 inches and 18% over 20 inches. The lower catches and fewer large fish observed in 2010 compared to recent assessments may partially be explained by an increase in small tullibees. During the assessment, some of the walleye sampled in nets near deep water were full of small tullibees. It is not uncommon for large walleye to utilize open water prey like tullibee during the summer and therefore these fish would not be vulnerable to our sampling methods.

The 2010 assessment evaluated a period in which walleye were stocked in 1999-2001, 2003-04, and 2007-08. At least 21% of the fish were the result of natural reproduction. Eight year-classes were identified by scale, opercle and otolith analysis. Walleye averaged 12.9 inches at after three years of growth, substantially less than the 14.2 inches observed in 2007. The slower growth was likely in response to the two shorter and cooler growing seasons of 2008 and 2009. However, the growth was still similar to the statewide averages.

The management plan goal for northern pike was to maintain a catch of 3.0 fish/gill net with 30-60% of the fish over 21 inches and 10-20% of the fish over 28 inches. Northern pike catches have ranged from 1.0 to 9.3 fish/net since 1946. Following the lowest catch on record (1.0 fish/net) in 2007, the catch improved to 2.5 fish/net in 2010. Northern pike ranged from 19.8 to 30.2 inches and averaged 22.7 inches. Four year-classes were identified by scales and cliethra with fish from 2 to 5 years old present. The age structure was dominated by two year old fish, representing 31 of the 37 fish sampled. Interestingly, all but one female northern pike were sexual mature even though they were small and young.

Black crappie are not sampled effectively in many lakes due to their behavior of suspending off the bottom away from shallow cover during the summer. The low population appears to be in response to the lake only having a few shallow, protected bays that are important for recruitment. The trap nets captured 12 fish for a catch of 0.8 fish/net. Gill nets only sampled two fish for a catch rate of 0.1 fish/net compared to 3.3 fish/net in 2007. The fish that were sampled were larger, ranging from 4.1 to 11.8 and averaged 10.0 inches. Four year-classes were identified from scales with fish from age 1 to age 6 present. Growth was similar to statewide averages for all ages.

Largemouth bass were sampled with night spring electrofishing in 2004 and 2010. The catch rate in 2004 was 34.9 fish/hr compared to 16.2 fish/hr in 2010. The timing of the sample and local weather patterns can affect sampling success as much as actual changes in population characteristics. The sampled fish ranged from 11.1 to 17.3 inches and averaged 15.1 inches. Seven year-classes were identified from scales with fish from age 4 to 10 present. There did not appear to be any dominant year-classes. Growth was similar to statewide averages for all ages.

Smallmouth bass populations appear to be expanding in many of the area lakes. Smallmouth bass were sampled with spring night electrofishing in 2004 and 2010. Only five fish were captured (2.5/hr) in 2004 and 14 in 2010 (7.1/hr). Summer gill nets are often effective for sampling smallmouth bass. The gill net catches in the last three assessments were 1.1 fish/net in 2004, 8.9 in 2007, and 6.6 in 2010. The fish sampled in 2010 by electrofishing ranged from 9.1 to 18.2 inches (average 14.0 inches) while the gill net sampled fish ranged from 6.4 to 19.0 inches (average 13.9 inches). Eight year-classes were identified from scales, opercles, and otoliths. Otoliths were generally too brittle and difficult to age. Fish from age 3 to age 11 were present with age 4 and 5 representing 73% of the sample. Growth was similar to the statewide average through age 4 and slower for older fish.

Tullibees are difficult to sample with our standard summer assessments due to their pelagic nature. As a result, tullibee catch rates are generally low but they can be highly variable. In 1946, the gill net catch rate was 23.3 fish/net and since that time catch rates have never been higher than 3.8 (1989). The decline may be a result of changes in water quality due to the land use practices within the watershed. In 2010, the gill-net catch rate was 0.1 fish/net. Interestingly, a number of walleye had stomachs packed with small tullibee.

The yellow perch population has experienced major fluctuations over the years. The gill net catch rates had progressively increased from 20.3 in 1984 to 169.3 in 1999 over five assessments, then decline substantially to 28.6 fish/net in 2004 but increased to 40.5 fish/net in 2007. The 2010 catch was 13.9 fish/net and fell below the lake class median of 17.1 fish/net for the first time. Yellow perch lengths ranged from 3.4 to 10.4 inches and averaged 6.6 inches. Due to the yellow perch size structure, they are probably more important within the fish community as a competitor and prey source than as a species desired by anglers.

Other species observed during the assessment included bowfin, brown bullhead, pumpkinseed sunfish, rock bass, white sucker, and yellow bullhead. Additional species observed while conducting sampling for IBI included banded killifish, central mudminnow, Iowa darter, Johnny darter, mottled sculpin, spottail shiner, and tadpole madtom.

In order to maintain or improve fish and wildlife populations, water quality and habitat must be protected. People often associate water quality problems with large-scale agricultural, forestry, urban development or industrial practices in the watershed. In reality, the impact of land use decisions on one lake lot may be relatively small, yet the cumulative impact of those decisions on many lake lots can result in a significant decline in water quality and habitat. For example, removing shoreline and aquatic vegetation, fertilizing lawns, mowing to the waters edge, installing beach sand blankets, failing septic systems and uncontrolled run-off, all contribute excess nutrients and sediment which degrade water quality and habitat. Understanding these cumulative impacts and taking steps to avoid or minimize them will help to insure our quality fisheries can be enjoyed by future generations.

For more information on this lake, contact: Area Fisheries Supervisor 1201 East Hwy 2 Grand Rapids, MN 55744 Phone: (218) 327-4430 Internet: Grand Rapids Fisheries E-Mail: GrandRapids.Fisheries@state.mn.us	Lake maps can be obtained from: Minnesota Bookstore 660 Olive Street St. Paul, MN 55155 (651) 297-3000 or (800) 657-3757 To order, use B0240 for the map-id.
For general DNR Information, contact: DNR Information Center 500 Lafayette Road St. Paul, MN 55155-4040 TDD: (651) 296-6157 or (888) MINNDNR Internet: www.dnr.state.mn.us E-Mail: info.dnr@state.mn.us	Turn in Poachers (TIP):     Toll-free: (800) 652-9093