Lake information report

Name: MOOSE, BIG

Public Access Information

Lake Characteristics

Fish Sampled up to the 2003 Survey Year

Length of Selected Species Sampled for All Gear for the 2003 Survey Year

Fish Consumption Guidelines

These fish consumption guidelines help people make choices about which fish to eat and how often. Following the guidelines 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 high enough to warrant a recommendation 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 06/16/2003)

Big Moose Lake is in Ecological Lake Class 16, which consists of 38 lakes in northeast Minnesota that are large and shallow, and have soft (unmineralized) and turbid (bog-stained) water. The Secchi water clarity of 12 ft on 6/16/2003 was higher than the average of 6 ft in previous investigations and also higher than the lake class average of 5.6 ft.

Big Moose Lake was partially thermally stratified on 06/16/2003 with a surface temperature of 72 F and a bottom temperature of 65 F. Good oxygen (6.8 ppm) was retained to the bottom on this date. Big Moose Lake has several inlets draining local wetlands. The outlet to the Moose River has rocky areas and shallow falls that limit fish movement. Lake bottom substrates along the shoreline are 75% boulder, 14% muck, 6% sand, and 5% ledgerock. Aquatic plants are sparse and grow to a depth of 4 ft; the most common aquatic plant is watershield.

The 2003 fish population assessment consisted of 6 standard gillnets set in mid June. It did not include trapnets due to the difficult access, and did not include the standard number of gillnet sets for a lake of this size (12 sets) to limit unnecessary walleye mortality. The purpose of the assessment was to determine if natural reproduction could maintain the walleye population at desired levels and if the apparent reduction in forage fish populations was affecting walleye growth. Five previous gillnet assessments, dating back to 1982, consisted of 3-6 gillnet sets.

The total catch of fish (all species combined) in 2003 of 24 fish/gillnet (36 lb/gillnet) was near the first quartile for this lake class. Walleye were introduced to this lake in 1983 and the total catch of fish in this lake has gradually declined from the initial investigation in 1982, which captured 93 fish/gillnet (62 lb/gillnet), most of which were perch and sucker. Lake Class 16 is one of the most productive lake classes in northeast Minnesota, in terms of gillnet catches of fish.

The introduction of walleye from 1983 through 1991 was accompanied by the decline in numbers of perch, sucker, and northern pike. Rock bass and smallmouth bass numbers have remained relatively stable over time.

Walleye numbers peaked in 1991 at 15/gillnet and gradually declined to their abundance in 2003 of 8.0/gillnet, which was at the median for this lake class. Walleye sizes in 2003 averaged 14.8" (1.3 lb), which was in the fourth quartile for this lake class and was similar to the average size of 14.2" in all investigations on this lake. The largest walleye captured in 2003 was 28.4" (6.9 lb). Ageing of walleye scales collected in 2003 was judged to be difficult, but walleye appeared to be present from 11 different year classes, only one of which (1991) was stocked with walleye. Growth of two year old walleye captured in 2003 was normal by area standards, while growth of all older year classes was slower than normal. Few age one or age three walleye were captured in 2003, which may have helped the growth of the two year olds. Growth of older walleye seemed especially slow. Most walleye stomachs that were examined were empty.

No yellow perch were captured in 2003. Perch numbers in 1982, prior to the introduction of walleye in 1983, were very high (54/gillnet). Perch numbers declined abruptly to 10/gillnet in 1986, then gradually declined to zero in the 2003 investigation. Perch sizes increased during this period, from an average of 8" in 1982 to an average of 10" in 1998.

White sucker numbers also declined over time, from 30/gillnet in 1982 to 8/gillnet in the 2003 investigation. Sucker sizes increased, from an average of 13" in 1982 to an average of 16" in 2003.

Northern pike numbers declined from 4.8/gillnet in 1982 to 1.7/gillnet in 2003. Pike sizes in 2003 averaged 22.8" (2.9 lb), which was in the fourth quartile for this lake class and was similar to their sizes in previous investigations. Pike scales were difficult to read, but only four year classes appeared to be represented in the gillnet catch. Pike growth appeared to be average by area standards.

Rock bass numbers in 2003 were in the fourth quartile for this lake class and were similar to the median catch of 2.0/gillnet (range: 0.6-2.8/gillnet) in previous investigations on this lake.

Smallmouth bass numbers in 2003 (3.7/gillnet) were in the fourth quartile for this lake class and were higher than the median catch of 1.7/gillnet (range: 0.5-2.7/gillnet) in previous investigations on this lake. Smallmouth sizes in 2003 averaged 13.5", which was similar to previous investigations. Growth of smallmouth captured in 2003 was faster than normal by area standards.

For more information on this lake, contact: Area Fisheries Supervisor 650 Hwy 169 Tower, MN 55790 Phone: (218) 753-2580 Internet: Tower Fisheries E-Mail: Tower.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 C0853 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