|Nearest Town: 24 mi. E & 6 mi. N of Ely
Primary County: Lake
|Survey Date: 05/31/2005|
Inventory Number: 38-0516-00
|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.|
|Did you know? MinnAqua Fishing: Get in the Habitat! has a Minnesota-base activity guide for teachers, scout and 4-H leaders, youth leaders, outdoor sports groups, or anyone interested in teaching others about habitat, stewardship and fishing.|
|Species||Number of fish per net||
Average Fish Weight (lbs)
Normal Range (lbs)
|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|
|Species||Number of fish caught in each category (inches)|
|For the record, the largest Brown Trout taken in Minnesota weighed 16 lbs., 12 oz. and was caught: |
Statistics: 31.4" length, 20.6" girth
Fish Stocked by Species for the Last Ten Years
|1 - indicates fish purchased and stocked by private citizens and sporting groups.|
|2 - indicates fish purchased by the DNR for stocking.|
|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.|
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:||Lake maps can be obtained from:|
For general DNR Information, contact:
DNR Information Center
500 Lafayette Road
St. Paul, MN 55155-4040
TDD: (651) 296-6157 or (888) MINNDNR
Turn in Poachers (TIP):
Toll-free: (800) 652-9093