Fisheries Lake Survey

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Name: St. Olaf

Nearest Town: Mankato
Primary County: Waseca
Survey Date: 06/14/2010
Inventory Number: 81000300

Public Access Information

Ownership Type Description
County Concrete Access at Park on N. shore of lake.

Lake Characteristics

Lake Area (acres): 91.2
Littoral Area (acres): 51
Maximum Depth (ft): 33
Water Clarity (ft): 4

Dominant Bottom Substrate: N/A
Abundance of Aquatic Plants: N/A
Maximum Depth of Plant Growth (ft): 7.0 (3-8.5)

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

Fish Sampled for the 2010 Survey Year


Gear Used

Number of fish per net

Average Fish Weight (lbs)

Normal Range (lbs)


Normal Range

Black Crappie Trap net 25.44 0.8 - 4.3 0.21 0.2 - 0.5
Bluegill Trap net 119.33 8.3 - 50.1 0.20 0.1 - 0.3
Common Carp Trap net 0.11 0.2 - 0.8 10.12 5.9 - 7.6
Golden Shiner Trap net 0.33 0.1 - 1.7 0.08 0.1 - 0.1
Hybrid Sunfish Trap net 0.78 N/A 0.26 N/A
Pumpkinseed Trap net 0.33 2.8 - 10.3 0.20 0.1 - 0.2
White Crappie Trap net 36.67 0.2 - 1.6 0.21 0.2 - 0.2
Normal Ranges represent typical catches for lakes with similar physical and chemical characteristics.

Length of Selected Species (Trapnet, Gillnet) Sampled for the 2010 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
black crappie 0 224 1 1 0 0 0 0 226
bluegill 204 865 0 0 0 0 0 0 1069
common carp 0 0 0 0 0 0 1 0 1
golden shiner 1 2 0 0 0 0 0 0 3
hybrid sunfish 2 5 0 0 0 0 0 0 7
pumpkinseed 1 2 0 0 0 0 0 0 3
white crappie 0 317 8 0 1 0 0 0 326

For the record, the largest Atlantic Salmon taken in Minnesota weighed 12 lbs., 13 oz. and was caught:

    Where: Baptism River, Lake County
    When: 10/12/91
    Statistics: 35.5" length, 16.5" girth

Fish Stocking Activity

Fish Stocked by Species for the Last Ten Years

Year Species Size Number Pounds
2014 northern pike fry 30,145 0.6
2013 Northern Pike fry 24,664 1.0
2011 Northern Pike fry 22,572 0.4
2010 Northern Pike fry 29,211 0.5
2009 Northern Pike fry 27,073 0.5
2005 Northern Pike fry 25,890 0.9

Stocking Notes
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.

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 06/14/2010)

Saint Olaf Lake was surveyed the week of June 14th, 2010 as part of the first phase of SLICE (Sentinel Lakes in a Changing Environment) monitoring. Trap net returns were similar to 2009 results. Ice out northern pike trap netting and early season vegetation point sampling were also completed. Largemouth bass electrofishing was not completed because the boat was not operational until late summer.

Black crappie averaged 25 fish per trap net lift. Bluegills averaged 119 fish per trap net lift. White Crappie averaged 37 fish per trap net lift. All bluegill and crappie catch per unit effort values exceeded the upper quartile for class 28 lakes. St. Olaf's centrarchid panfish community is largely made up of small and characteristically stunted fish.

Other fish caught include common carp, golden shiner, hybrid sunfish, and pumpkinseed.

Beach seines and backpack electrofishing as part of Index of Biotic Integrity sampling found species captured in trap nets, as well as spottail shiner, yellow perch, northern pike and johnny darter.

Anglers can help maintain or improve the quality of fishing by practicing selective harvest. Selective harvest allows for the harvest of smaller fish for table fare, but encourages release of medium- to large-sized fish. Releasing these fish can help maintain balance in the fish community in St. Olaf Lake and provide anglers the opportunity to catch more and larger fish in the future.

Shoreline areas on the land and into the shallow water provide essential habitat for fish and wildlife that live in or near Minnesota's lakes. Overdeveloped shorelines cannot support the fish, wildlife, and clean water that are associated with natural undeveloped lakes. Shoreline habitat consists of aquatic plants, woody plants, and natural lake bottom soils.

Plants in the water and at the water's edge provide habitat, prevent erosion, and absorb excess nutrients. Shrubs, trees, and woody debris such as fallen trees or limbs provide good habitat both above and below the water and should be left in place. By leaving a buffer strip of natural vegetation along the shoreline, property owners can reduce erosion, help maintain water quality, and provide habitat and travel corridors for wildlife.

For more information on this lake, contact:

Area Fisheries Supervisor
PO Box 86
50317 Fish Hatchery Rd
Waterville, MN 56096-0086
Phone: (507) 362-4223
Internet: Waterville Fisheries

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 C0758 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

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    Toll-free: (800) 652-9093