Fisheries Lake Survey

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Name: AHSUB

Nearest Town: 24 mi. E & 6 mi. N of Ely
Primary County: Lake
Survey Date: 05/31/2005
Inventory Number: 38-0516-00

Public Access Information

Ownership Type Description
US Forest Service Carry-in 1/8 mile portage from Disappointment Lake in the BWCAW.
US Forest Service Carry-in 1/8 mile portage from Jitterbug Lake in the BWCAW.


Lake Characteristics

Lake Area (acres): 58.00
Littoral Area (acres): 22.00
Maximum Depth (ft): 78.00
Water Clarity (ft): 16.00

Dominant Bottom Substrate: N/A
Abundance of Aquatic Plants: N/A
Maximum Depth of Plant Growth (ft): N/A


Did you know? Spawning habitat improvements can enhance naturally reproducing populations of fish species such as walleye and northern pike.

Fish Sampled up to the 2005 Survey Year

Species

Gear Used

Number of fish per net

Average Fish Weight (lbs)

Normal Range (lbs)

Caught

Normal Range

Brook Trout Gill net 3.7 N/A - N/A 0.37 N/A - N/A
White Sucker Gill net 11.7 0.8 - 5.3 3.11 1.1 - 2.5
Normal Ranges represent typical catches for lakes with similar physical and chemical characteristics.


Length of Selected Species Sampled for All Gear for the 2005 Survey Year

Species Number of fish caught in each category (inches)
0-5 6-8 9-11 12-14 15-19 20-24 25-29 30+ Total
Brook Trout 0 10 0 0 1 0 0 0 11


For the record, the largest Shorthead Redhorse taken in Minnesota weighed 7 lbs., 15 oz. and was caught:

    Where: Rum River near Ramsey, Anoka County
    When: 8/5/83
    Statistics: 27" length, 15" girth

Fish Stocking Activity

Fish Stocked by Species for the Last Ten Years

Year Species Size Number Pounds
2010 Brook Trout fingerlings 4,384 116.0
2008 Brook Trout fingerlings 5,049 153.0
2007 Brook Trout fingerlings 4,368 130.0
2006 Brook Trout fingerlings 4,359 126.0
2005 Brook Trout fingerlings 4,575 150.0
2004 Brook Trout fingerlings 4,340 124.0

Privately Stocked Fish
* indicates privately stocked fish. Private stocking includes fish purchased by the DNR for stocking and fish purchased and stocked by private citizens and sporting groups.

Stocking Fish Sizes
Fry - Newly hatched fish that are ready to be stocked usually called "swim-ups". Walleye fry are 1/3 of an inch or around 8 mm.
Fingerling - Fingerlings are one to six months old and can range from a size of one to twelve inches depending on the species. Walleye fingerlings range from three to eight inches each fall.
Yearling - Yearling fish are at least one year old. A one-year-old fish can range from three to twenty inches depending on the species. Walleye yearlings average from six to twelve inches.
Adult - Adult fish are fish that have reached maturity. Depending on the species, maturity can be reached at two years of age. Walleye reach maturity between the ages of four and six years.

Fish Consumption Guidelines

No fish consumption guidelines are available for this lake. For more information, see the "Fish Consumption Advice" pages at the Minnesota Department of Health.


Status of the Fishery (as of 05/31/2005)

Ahsub Lake is in Ecological Lake Class 3, which consists of 72 lakes in northeast Minnesota that are deep, have irregularly shaped shorelines, and have clear and soft (unmineralized) water. Ahsub Lake is smaller than most of the lakes in this lake class.

Ahsub Lake was thermally stratified on 05/31/2005 with a surface temperature of 63 F and a bottom temperature of 39 F. Good oxygen for trout (more than 5 ppm) was retained to a depth of 40 ft, where the temperature was 41 F. Ahsub Lake has no inlets. The outlet has a filter barrier (which is in disrepair) and a beaver dam with a 3 ft head that limits fish movement upstream from Jitterbug Lake. Bottom substrates along the shoreline of Ahsub Lake are 40% ledgerock, 40% boulder, 10% rubble, and 10% muck. Aquatic plants are sparse and grow to a depth of 15 ft; there is a concentration of plants in the shallow outlet bay.

Ahsub lake was first surveyed with gillnets in 1966, and was poisoned in 1967 to remove populations of northern pike, white sucker, and yellow perch. Trout stocking began in 1969. Eight subsequent trout assessments each consisted of 2-4 gillnets, mostly done in late May or early June, or in October. Trapnetting has not been done in this lake due to the difficult portage access, and shoreline seining has not been done due to the lack of suitable seining areas.

Fish species captured in 2005 were brook trout and white sucker. A dozen smallmouth bass nests were observed by the survey crew, and one of these nests was occupied. Smallmouth bass were first reported in Ahsub Lake by anglers in 1997.

Brook trout biomass in 2005 (1.4 lb/gillnet) was lower than the average trout catch of 7.7 lb/gillnet (all species) in previous assessments on this lake and was also lower than the median trout catch of 3.9 lb/gillnet (all species) in recent assessments of 25 stream trout lakes (excluding mine pit lakes) in the Tower Fisheries Management Area.

Ten of 11 brook trout captured in 2005 ranged in size from 6" to 8" and had been stocked the previous fall as fingerlings. One 18" brook trout was also captured. The stomachs of the small trout were empty, while the stomach of the large brook trout contained chironomids and dragonfly larvae.

White sucker numbers in 2005 (11.7/gillnet) were similar to the average catch of 11.9/gillnet in previous trout assessments on this lake.


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 C5044 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

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