Fisheries Lake Survey

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Name: Minnetonka

Nearest Town: Mound
Primary County: Hennepin
Survey Date: 06/18/2012
Inventory Number: 27013300
Buy your walleye stamp todayPurchase a walleye stamp. Your voluntary contribution will be used to support walleye stocking.

Public Access Information

Ownership Type Description
City Concrete Carson's Bay Access
DNR Concrete Maxwell Bay Access
DNR Concrete North Arm Access
DNR Concrete Gray's Bay Access
City Concrete Cook's Bay Access
County Concrete Spring Park Bay Access


Lake Characteristics

Lake Area (acres): 14729.56
Littoral Area (acres): 5849
Maximum Depth (ft): 113
Water Clarity (ft): 7.7 (1.5-22)

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


Did you know? Each year, DNR fisheries personnel stock game fish fry and fingerlings in lakes lacking habitat for natural reproduction.

Fish Sampled for the 2012 Survey Year

Species

Gear Used

Number of fish per net

Average Fish Weight (lbs)

Normal Range (lbs)

Caught

Normal Range

Black Bullhead Gill net 0.25 0.5 - 4.1 0.68 0.6 - 1.0
Black Crappie Gill net 3.42 0.2 - 1.1 0.20 0.2 - 0.5
Bluegill Gill net 34.17 N/A 0.18 N/A
Green Sunfish Gill net 0.17 0.1 - 0.5 0.05 N/A
Hybrid Sunfish Gill net 0.58 N/A 0.13 N/A
Largemouth Bass Gill net 0.17 0.3 - 1.2 0.98 0.6 - 1.0
Northern Pike Gill net 11.17 3.0 - 7.9 2.91 1.7 - 2.8
Pumpkinseed Gill net 0.92 N/A 0.13 N/A
Rock Bass Gill net 1.08 1.0 - 6.6 0.23 0.3 - 0.5
Smallmouth Bass Gill net 0.08 0.2 - 0.9 0.58 0.9 - 1.8
Walleye Gill net 4.25 4.0 - 9.6 2.72 1.1 - 1.9
White Sucker Gill net 0.33 1.0 - 3.5 2.32 1.5 - 2.3
Yellow Bullhead Gill net 0.75 0.6 - 6.4 0.81 0.6 - 0.9
Yellow Perch Gill net 13.42 7.1 - 33.9 0.14 0.1 - 0.2
Normal Ranges represent typical catches for lakes with similar physical and chemical characteristics.


Length of Selected Species (Trapnet, Gillnet) Sampled for the 2012 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 bullhead 0 1 1 1 0 0 0 0 3
black crappie 8 29 3 0 0 0 0 0 41
bluegill 122 282 0 0 0 0 0 0 410
green sunfish 2 0 0 0 0 0 0 0 2
hybrid sunfish 5 2 0 0 0 0 0 0 7
largemouth bass 0 0 0 2 0 0 0 0 2
northern pike 0 0 0 2 32 62 29 8 134
pumpkinseed 9 2 0 0 0 0 0 0 11
rock bass 6 7 0 0 0 0 0 0 13
smallmouth bass 0 0 1 0 0 0 0 0 1
walleye 0 0 3 8 18 21 0 0 51
white sucker 0 0 0 0 4 0 0 0 4
yellow bullhead 0 0 6 3 0 0 0 0 9
yellow perch 35 123 1 0 0 0 0 0 161


For the record, the largest Ohrid Trout taken in Minnesota weighed 6 lbs., 6 oz. and was caught:

    Where: Tofte Lake, Lake County
    When: 1/9/73
    Statistics: 25" length

Fish Stocking Activity

Fish Stocked by Species for the Last Ten Years

Year Species Size Number Pounds
2013 Walleye1 yearlings 2,502 417.0
2012 Muskellunge yearlings 215 233.2
  Muskellunge1 fingerlings 1,200 232.1
  Walleye2 fingerlings 113,471 6,444.1
2011 Muskellunge yearlings 88 67.7
  Muskellunge2 fingerlings 1,200 226.4
2010 Walleye1 fingerlings 35,416 2,167.5
  Walleye1 fingerlings 66,137 4,274.6
2009 Muskellunge adults 46 46.0
  Muskellunge1 fingerlings 703 175.8
  Muskellunge1 fingerlings 511 127.8
  Muskellunge yearlings 372 186.0
2008 Muskellunge adults 103 454.1
  Muskellunge yearlings 35 17.5
  Muskellunge1 fingerlings 305 112.1
  Walleye1 fingerlings 27,177 1,606.7
  Walleye1 fingerlings 98,947 4,841.3
2007 Muskellunge adults 351 1,103.0
  Muskellunge1 adults 51 63.8
  Muskellunge fingerlings 425 65.2
  Muskellunge1 fingerlings 2,500 776.4
  Muskellunge1 yearlings 99 33.0
2006 Muskellunge adults 744 1,804.1
  Muskellunge1 yearlings 383 138.9
  Walleye fingerlings 9,030 492.1
  Walleye1 fingerlings 116,307 5,958.5
2005 Muskellunge1 fingerlings 380 122.6
2004 Walleye1 fingerlings 123,456 5,346.2

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

These fish consumption guidelines help people make choices about which fish to eat and how often. Following the guidelin es 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

LAKE NAME
County, DOWID
Species Meal Advice Contaminants
Unrestricted 1 meal/week 1 meal/month Do not eat
MINNETONKA
Hennepin Co., 27013300
Bluegill Sunfish   All sizes     Mercury
Carp   All sizes     Mercury
Crappie All sizes        
Largemouth Bass   All sizes     Mercury
Northern Pike   All sizes     Mercury
Walleye   shorter than 18" 18" or longer   Mercury
White Sucker All sizes        

General Population

LAKE NAME
County, DOWID
Species Meal Advice Contaminants
Unrestricted 1 meal/week 1 meal/month Do not eat
MINNETONKA
Hennepin Co., 27013300
Bluegill Sunfish All sizes        
Carp All sizes        
Crappie All sizes        
Largemouth Bass All sizes        
Northern Pike   All sizes     Mercury
Walleye   All sizes     Mercury
White Sucker All sizes        

DOWID - MN DNR, Division of Waters' lake ID number.

Contaminants listed were measured at levels that trigger advice 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 06/18/2012)

The 2012 Lake Minnetonka (27-0133-00) fisheries assessment was conducted June 18th through 28th. Annual sampling began in 1997 following a 20-year period when the fish community was sampled every five years. Sampling in Lake Minnetonka is divided into three aggregations of basins that differ in their habitat and water chemistry characteristics. The Northwest Bays are most fertile, primarily because they are the first recipients of the majority of surface runoff from the watershed. The Upper Lakes are intermediate in fertility, while the Lower Lakes are least fertile.

Since 1997, assessments have been conducted every year to assess trends in growth, condition, relative abundance, reproduction, and size structure of northern pike, walleye, and yellow perch. Sampling of these species typically involves 24 experimental gill net sets at 12 historic locations (24-hr sets; 2 net sets at each location with approximately 7-9 days between net sets. However, due to budget and staffing constraints, only one circuit of 12 net sets was completed in 2012. In May 2011, an electrofishing special assessment was conducted to evaluate the status of the largemouth bass population. That year-old data is included in this report. The 2012 gill net assessment revealed a diverse fish community (14 species) dominated (based on lbs/gillnet) by northern pike (32.3 lbs/net), walleye (11.4 lbs/net), and bluegill (6.1 lbs/net).

Water Quality Water quality trends in Lake Minnetonka indicate a positive change in average Secchi depth and anoxic depth (< 2 ppm dissolved oxygen) over time. Secchi depths in 2012 were generally shallower than 2011 in the Upper Lakes and Northwest Bays; however, the trends in Secchi depth for all three basins show a positive relationship for increasing water clarity. The same positive relationship is also true of historical anoxic depths. The Lower Lakes have the best water quality, followed by the Upper Lakes, then Northwest Bays.

Walleye Lake Minnetonka is stocked with 6,446 pounds of fingerling walleye in even-numbered years. This equates to 1.1 lbs/littoral acre. Starting in the fall of 2010, walleye were and will continue to be stocked into all three basins of the lake. For more than 30 years, previous management limited walleye stocking locations to the Upper Lake and Lower Lake basins. Since 2004, most or all of the walleye stocked were purchased from Minnesota-based fish farmers.

Despite extensive stocking, walleye abundance, as indicated by gill net catch per unit effort, has remained at low levels. Since 1977, 20 surveys have been conducted on Lake Minnetonka; of these, 12 had walleye catch rates below 4.0 fish/net. The 2012 catch of 4.3 fish/net is higher than that of 2011 (3.5/net), and for the first time since 2007, is near the long term average (4.2/net; 1997-2011). On an entire-lake basis, walleye abundance was higher than the previous 4 years; however, catch rates differed by basin. In Upper lakes, walleye catch rate increased from 2.9 to 3.5 per net since 2011. In the Northwest Bays, catch increased from 3.5 to 5.7 walleye per net. In Lower Lakes, no considerable change in walleye abundance (4.0/net) was observed from 2011. The long-term (1997-2010) average walleye gill net catch per net for Upper Lakes is 4.1, 4.8 in Lower Lakes, and 3.3 in the Northwest Bays. Walleye catch rate in the Northwest Bays has been increasing since 2010 and in 2012 it was the highest observed in 12 years. This may be related to the increased distribution of stocked fish into those bays of the lake.

A comparison of northern pike and walleye catch rates suggests an inverse relationship. For example, the second lowest walleye catch rate (1.5 fish/net) occurred in 2005, three years after the second highest northern pike catch rate (17.7 fish/net). The high northern pike catch rate in 2002 represents a large population of northern pike in Lake Minnetonka that could have preyed upon the walleye fingerlings stocked in that year. Since walleye are recruited to gill nets by age 3, this predation was evident three years later (2005) when they were large enough to be sampled. This relationship was also evident from 1999 through 2001. However, northern pike numbers have been decreasing since 2002 (with the exception of 2012) and show no relationship with relative walleye abundance. During that same time period (2002-2012), walleye abundance also showed no relationship with yellow perch abundance.

Walleye mean weight in 2012 (2.7 lbs) exceeded the 75th percentile (1.9 lbs) when compared to other similar lakes, and this has been the case since at least 1992. Mean weight was highest in the Upper Lakes (3.3 lbs), followed by the Northwest Bays (2.9 lbs), and the Lower Lakes (2.1 lbs). The general trend over time has been for the largest walleyes to be located in the Northwest Bays, followed by Upper Lakes, then Lower Lakes. This is assumed to be related to the productivity of the basins and the amount of yellow perch available as prey. Historically, the physical condition of walleye in Lake Minnetonka has been good. A relative weight value of 100 indicates the fish is in the 75th percentile for weight, relative to its length (above average condition). In 2012, walleye body condition was above the average of the previous 15 years and was similar among all three basins of the lake.

After walleye mean length exceeded 20 inches for the first time ever in the 2011 assessment, mean length decreased in 2012 to a value more similar to other recent assessments. Walleye averaged 18.6 inches in length and ranged from 11.0 to 24.4 inches. Following the same trend as mean weight, mean length was highest in the Upper Lakes (20.1 inches), followed by Northwest Bays (19.0 inches), and Lower Lakes (17.2 inches). Historically, size structure indices have revealed Lake Minnetonka's walleye population consists of larger individuals and this was again observed in 2012; however, values were lower than those of recent years. The proportion of walleye 20 inches and larger had increased every year for the last 5 until the 2012 assessment. Forty-two percent were 20 inches or larger in 2012, which is lower than the 2011 value, but still higher than the long-term (1997-2011) average of 34%. The proportion of 15-inch and longer walleye has fluctuated over the same time period and has averaged 80% in the last 15 years. In 2012, the highest proportion of larger fish was in the Upper Lakes, followed by the Lower Lakes, then the Northwest Bays.

Aging walleyes using otoliths (bones within the skull) allowed year-class inferences to be made. Consistent with previous assessments, walleye natural reproduction is limited. In 2012, 3 of 46 (6.5%) walleye originated from a non-stocked year-class. This was lower than 2011, when 16.0 % were determined to be naturally reproduced. The two most abundant year classes were 2008 (age-4) and 2010 (age-2); each was equally present and together constituted 52% of the walleye catch. The strong 2004 (age-8) and 2006 (age-6) year classes observed in 2011 were still present, representing 15 and 9% of the catch, respectively. The oldest walleye sampled was a 19- year old fish that was a 23.4-inch, 4.6-lb male.

Growth of walleye sampled in 2012 was similar to that of previous assessments. In general, walleye grew to 11.6 inches by age-3 and 18.2 inches by age-6, however there were gender-related differences. Males grew slower, but reached older ages. An age-3 female averaged 13.6 inches, while an age-3 male averaged 10.9 inches. Trends in growth were similar in all three basins, although young walleye (age-1 and 2) grew fastest in the Northwest Bays and older ages grew fastest in the Lower Lakes.

Northern Pike Consistent with recent assessments, northern pike were relatively high in abundance in 2012. On an entire-lake basis, the 2012 northern pike catch of 11.2/net ended a streak of 9 consecutive years showing decreasing relative abundance (6.3/net in 2011). The current assessment was the first time since 2008 that relative abundance was above 7.9/net, where it had consistently been between 1987 and 2008.

Northern pike catch rates in the Lower Lakes (14.8 fish/net) exceeded catch rates in both the Northwest Bays (10.3 fish/net) and Upper Lakes (7.3 fish/net). Northern pike average size (2.89 lbs) was similar to 2011 (3.08 lbs). Northern pike averaged 22.8 inches in length, which was similar to 2011 (23.0 inches) and was at the long-term average of 22.8 inches (1992-2011, spanning 16 surveys). Northern pike mean length was similar in all three basins (Northwest Bays = 23.9 inches, Upper Lakes = 23.5 inches, Lower Lakes = 22.1 inches). Relative weight (90) was good and near the historic average (89). Northern pike condition was similar among all three basins. The largest individual captured was an age-7 female (33.7 inches, 10.8 lbs).

Size structure indices revealed a quality northern pike population. Fifty-one percent were 21 inches or longer and 10% were 28 inches or longer. The best size structure found in the Northwest Bays where 52% were 21 inches or longer and 13% were 28 inches or longer. Growth rates were similar to other West Metro Management Area lakes. On average, northern pike in Lake Minnetonka were 20.7 inches by age-3 and 26.8 inches by age-6, although growth did differ, as expected, by gender. Females reached older ages and consistently grew faster. For example, an age-6 female was 28.0 inches compared to a 21-inch male that same age. Growth was similar among the basins. Nine year-classes were sampled, with most fish (80%) between 2 and 5 years old.

Yellow Perch After a historical high of 31.7 yellow perch/net in 2011, the 2012 catch (13.4/net) returned to near the long-term (1997-2011) average of 14.2/net. Yellow perch relative abundance (13.4/net) in 2012 was moderate compared to other similar lakes. Despite a drop in 2012 (lowest since 2004), the overall trend since 2000 has been for increasing yellow perch gill-net catch. In most previous surveys, yellow perch abundance was highest in the Northwest Bays, but in 2012, the highest catch was in the Upper Lakes (25.5/net), followed by the Northwest Bays (18.7/net), then the Lower Lakes (0.6/net). Gill-net catch was down in all three basins. Over time, there has been an inverse relationship between yellow perch and northern pike abundance. Recently, this appears to be evident as yellow perch gill-net catch peaked in 2011, and in 2012 northern pike abundance increased for the first time since 2002.

Size structure indices revealed a population consisting of small individuals, and this has historically been the case. Yellow perch mean length (6.7 inches) and weight (0.14 lbs) were similar to 2011. The perch population in the Northwest Bays has a better size structure than the other two basins. In 2012, however, the largest mean size was in the Upper Lakes (6.8 inches, 0.14 lbs).

Yellow perch relative weight (86) was fair and the same as 2011, but lower than the historical average of 90. Seven year-classes were sampled with the oldest individual captured age-8. Recruitment seemed consistent as ages 2 through 5 were relatively evenly represented. Yellow perch growth was slower on average than other similar lakes in the West Metro Management Area. Comparing basins, yellow perch grew fastest in the Northwest Bays, followed by Lower Lakes, then Upper Lakes. Yellow perch averaged 5.4 inches by age 3, and 7.5 inches by age 6.

Muskellunge Muskellunge were not targeted during this assessment, but based on other measures and reports, their population remains strong. Fish exceeding 50 inches and approaching 40 pounds are caught in Lake Minnetonka every year. Survival of stocked fingerling muskellunge is assumed to be low due to the high abundance of largemouth bass and northern pike. Advanced fingerlings and yearlings have been used in recent years in attempt to improve survival rates of stocked fish. A research study is currently taking place in Lake Minnetonka comparing the survival of stocked fingerling and yearling muskellunge. Stocked fish were tagged in 2008, 2009, 2011, and 2012. These muskellunge were tagged with an external spaghetti-type tag near the dorsal fin on the fish's left side. These tags are yellow in color and each includes a unique six-digit number. Angler reports of captured tagged muskellunge are essential to the success of this project. If you catch a tagged muskellunge please record the tag number and length of fish and report the catch via the Tagged Fish Reporting page within the MNDNR website. Please DO NOT remove the tag. Please contact the West Metro Fisheries Office with questions. Practicing CPR (Catch, Photo, and Release) is essential to maintaining the trophy muskellunge fishery found in Lake Minnetonka.

Largemouth Bass The largemouth bass population in Lake Minnetonka has a reputation for quality fishing. In May 2011, nighttime boat electrofishing was performed to assess the largemouth bass population. A total of 385 largemouth bass were sampled in 11 electrofishing transects, equating to 75.4 bass per hour. Catch rates were similar to the 2009 assessment, when 73.2 bass per hour were sampled. These catch rates are above average for area lakes. The size structure of the largemouth bass population in Lake Minnetonka is well-balanced and the fish are in good physical condition. It appeared the larger fish tended to be in the best condition. Largemouth bass averaged 11.8 inches and 1.04 lbs, which is lower than in 2009 when fish averaged 13.5 inches and 1.5 lbs. In 2011, 52% were 12 inches or longer, 24% were 15 inches or longer, and 1% were 20 inches or larger. The largest bass sampled was 20.9 inches long and 4.9 lbs. Fish from the 1999 through 2009 year classes were present, indicating consistent reproduction and recruitment. Age-3 bass from the 2008 year class were most abundant (25%), followed by the 2007 (23% of the total) and 2005 (9.4% of the total) year classes. Growth was slower than average compared with other West Metro Area lakes. Largemouth bass reached 14 inches by age 7 and 18 inches by age 11. No smallmouth bass were sampled during the spring electrofishing assessment.

Numerous bass tournaments are held on the lake every year. These tournaments are held by permit only and fish data must be turned into the DNR. In 2012, 10 bass tournaments were held. A total of 869 tournament anglers caught 1,989 largemouth bass. Average size was 2.73 lbs and the largest recorded was 6.25 lbs. Since bass anglers target the largest individuals in a population, it is common for angling results to yield larger size fish, on average, than electrofishing. Additionally, individual tournaments may enact their own minimum size limit, thus only measuring larger size fish. The electrofishing assessment targeted all sizes of bass.

Other Fish Species Bluegill and black crappie are abundant in Lake Minnetonka; however, gill nets are not reliable indicators of their relative abundance. The consistent natural reproduction and high recruitment of these species have ensured quality angling opportunities. Black bullhead, green sunfish, hybrid sunfish, pumpkinseed sunfish, rock bass, smallmouth bass, white sucker, and yellow bullhead were also captured in low numbers during the 2012 assessment. Smallmouth bass and rock bass were found only in the Lower Lakes.

Invasive Aquatic Species Eurasian water milfoil and curly leaf pondweed are found in high abundance throughout the lake and in 2010 zebra mussels and flowering rush were first found to be present. Lake Minnetonka receives heavy recreational use, so potential for the spread of invasive species into and out of the lake is high. Anglers and boaters should take the precautions necessary to prevent the further spread of all invasive species.

The shoreline and watershed of Lake Minnetonka is highly developed and puts stress on the lake's aquatic habitat and ecosystem integrity. Large docks, boating platforms, and man-made beaches have the potential to destroy vital habitat for fish and wildlife. Environmentally friendly development practices, such as shoreline buffer strips of natural vegetation, are necessary to maintain the current water quality of Lake Minnetonka. Shoreline development, invasive species, and the fish diseases Viral Hemorrhagic Septicemia (VHS) and Largemouth Bass Virus should be a concern to everyone who enjoys lake recreation.


For more information on this lake, contact:

Area Fisheries Supervisor
7050 E Hwy 101, Suite 100
Shakopee, MN 55379
Phone: (952) 496-4141
Internet: West Metro Fisheries
E-Mail: MetroWest.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 B0122 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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    Toll-free: (800) 652-9093