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D

Whaletail Lake

Hennepin County, MinnesotaEutrophic

On the scoring rubric Whaletail Lake grades a D: clarity at 3.3 ft and 48 µg/L of phosphorus keep it in the lower bracket for Hennepin County. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Minnesota norms.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Whaletail Lake reaches 22 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Whaletail Lake covers 510 acres alongside 6.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Whaletail Lake ranks 37 of 95 in Hennepin County — solidly in the upper half of the local distribution.

Eurasian watermilfoil is established at Whaletail Lake, which can dampen recreational access and pressure the native plant community. The fishery is bass-led, with 13 documented species across the lake's records. A documented public access point at Whaletail Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a partial ice record — 9 observed ice-outs, centered near Apr 8. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-09. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Very murky, less than 3.3 ft of visibility. Phosphorus level: 47.6 µg/L. Trophic State Index: 60.

MetricValueGrade
Water Clarity (Secchi Depth)3.3 ftF
Phosphorus47.6 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)60Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth22 ft
Surface Area510.03 acres
Shoreline Length6.9 mi
Littoral Zone92%
Public AccessYes

Fish Species

black bullhead,black crappie,bluegill,brown bullhead,common carp,green sunfish,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,white crappie,yellow bullhead,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Whaletail Lake (14-day solunar calendar)

→ Is it safe to eat fish from Whaletail Lake? (mercury & PFAS guide)

Whaletail Lake fishing regulations (limits, seasons, special rules)

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Eurasian watermilfoil

Water Quality Trend: Improving

Based on 4 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.555 m/yr4
Phosphorus Improving-4.25 µg/L/yr3
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (13 observations).

Typical Ice-Out
Apr 8
Typical Ice-In
Nov 30

Estimated open water season: 236 days

EarliestLatest
Ice-Out2024-03-03 (2024)2018-05-01 (2018)
Ice-In1997-11-15 (1997)1999-12-14 (1999)

Most recent ice-out: 2024-03-03

Location

Loading map…

County Ranking

Ranked #37 of 95 lakes in Hennepin County

Cleaner Lakes Within 30 Miles

Whaletail Lake holds Grade D. 3 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Hennepin County

Compare Whaletail Lake With Nearby Lakes

DNR Fisheries Survey Summary

9 surveys on file from MN DNR Fisheries. Most recent: 2021-07-26 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Crappie45.960.16 lb
Bluegill20.040.15 lb
White Crappie12.450.21 lb
Yellow Perch8.260.11 lb
Yellow Bass4.840.78 lb
Brown Bullhead3.370.83 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Black Crappie

156 fish · 49 in · 2021-07-26
47240trophy 10456789

Bluegill

408 fish · 38 in · 2021-07-26
150750345678

White Crappie

3 fish · 59 in · 2021-07-26
210trophy 1056789

Yellow Perch

80 fish · 57 in · 2021-07-26
53270567

From the 2021-07-26 survey

Whaletail Lake is 510-acres (469 littoral acres) with a maximum depth of 22 feet. Whaletail is located northeast of St. Bonifacious in southwestern Hennepin County. Public water access is provided by DNR Parks and Trails on the northwest side of the lake off of County road 92 and West Highland road (up to 16…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Whaletail Lake. 2 reports on file.

EPA Impairment Status

Whaletail Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN27-0184-02 · Official waterbody report · Matched by proximity (0.51 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Lake details from Minnesota DNR LakeFinder

Ice data from Minnesota DNR Climate

Most recent sample: 2023-10-09

Monitoring stations: 2