Fisheries Lake Survey

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Name: Grindstone

Nearest Town: Sandstone
Primary County: Pine
Survey Date: 07/30/2012
Inventory Number: 58012300

Public Access Information

Ownership Type Description
DNR Concrete North West side of Lake.


Lake Characteristics

Lake Area (acres): 532.91
Littoral Area (acres): 71.3
Maximum Depth (ft): 153
Water Clarity (ft): 11.5 (10.1-12.9)

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


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.

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 Crappie Trap net 2.56 0.5 - 2.2 0.36 0.3 - 0.5
Gill net 0.17 0.3 - 1.7 0.12 0.2 - 0.5
Bluegill Trap net 28.44 7.7 - 43.4 0.17 0.1 - 0.2
Gill net 0.33 N/A 0.10 N/A
Brown Trout Gill net 0.38 N/A 1.08 N/A
Greater Redhorse Trap net 0.67 N/A 4.06 N/A
Hybrid Sunfish Trap net 0.11 N/A 0.08 N/A
Lake Trout Gill net 2.00 0.2 - 1.7 1.75 1.6 - 4.8
Largemouth Bass Trap net 0.11 0.4 - 1.5 0.20 0.2 - 0.7
Northern Pike Trap net 0.22 N/A 1.14 N/A
Gill net 0.75 2.2 - 8.7 4.36 1.5 - 3.2
Pumpkinseed Trap net 0.89 1.4 - 5.9 0.08 0.1 - 0.2
Rainbow Smelt Gill net 3.04 N/A 0.11 N/A
Rainbow Trout Gill net 0.04 N/A 2.20 N/A
Rock Bass Trap net 2.56 0.8 - 3.7 0.16 0.2 - 0.4
Gill net 0.25 0.7 - 4.4 0.10 0.2 - 0.4
Smallmouth Bass Trap net 0.44 0.2 - 0.8 0.13 0.2 - 0.7
Gill net 0.17 0.2 - 1.6 1.52 0.8 - 1.8
White Sucker Trap net 0.11 0.2 - 0.7 2.20 1.0 - 2.8
Gill net 0.12 0.5 - 2.0 1.91 1.6 - 2.6
Yellow Bullhead Gill net 0.04 1.0 - 6.0 1.57 0.4 - 0.7
Yellow Perch Gill net 0.79 1.5 - 13.8 0.11 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 crappie 6 16 5 0 0 0 0 0 27
bluegill 127 131 0 0 0 0 0 0 264
brown trout 0 0 0 6 3 0 0 0 9
greater redhorse 0 0 0 0 0 6 0 0 6
hybrid sunfish 1 0 0 0 0 0 0 0 1
lake trout 0 5 12 8 10 13 0 0 48
largemouth bass 0 1 0 0 0 0 0 0 1
northern pike 0 0 0 1 4 4 9 2 20
pumpkinseed 8 0 0 0 0 0 0 0 8
rainbow smelt 7 57 9 0 0 0 0 0 73
rainbow trout 0 0 0 0 1 0 0 0 1
rock bass 19 9 1 0 0 0 0 0 29
smallmouth bass 3 1 0 2 2 0 0 0 8
white sucker 0 0 0 1 3 0 0 0 4
yellow bullhead 0 0 0 1 0 0 0 0 1
yellow perch 0 18 0 0 0 0 0 0 19


For the record, the largest White Bass taken in Minnesota weighed 4 lbs., 2.4 oz. and was caught:

    Where: Mississippi River Pool 5, Wabasha County
    When: 5/4/2004

Fish Stocking Activity

Fish Stocked by Species for the Last Ten Years

Year Species Size Number Pounds
2013 Brown Trout yearlings 1,000 302.0
  Brown Trout adults 1,500 1,250.0
  Lake Trout yearlings 5,250 555.0
  Rainbow Trout yearlings 9,000 4,396.0
2012 Brown Trout yearlings 2,500 2,000.0
  Rainbow Trout yearlings 9,000 3,872.0
2011 Brown Trout yearlings 2,500 1,785.7
  Lake Trout yearlings 5,960 522.8
  Rainbow Trout yearlings 8,999 4,441.2
2010 Brown Trout yearlings 2,000 307.2
  Lake Trout adults 433 683.0
  Rainbow Trout yearlings 8,166 4,134.2
2009 Brown Trout adults 2,500 1,700.7
  Rainbow Trout yearlings 5,000 2,262.4
  Rainbow Trout yearlings 2,838 3,638.0
2008 Rainbow Trout yearlings 3,000 2,000.0
2007 Brown Trout yearlings 2,500 625.0
  Lake Trout yearlings 5,385 469.6
  Lake Trout adults 75 115.6
  Lake Trout adults 57 150.8
  Rainbow Trout yearlings 7,700 4,169.7
2006 Brown Trout adults 130 469.3
  Brown Trout yearlings 5,000 885.0
  Rainbow Trout adults 77 447.7
  Rainbow Trout yearlings 11,400 5,318.8
2005 Brown Trout yearlings 2,500 371.5
  Lake Trout yearlings 5,353 536.2
  Rainbow Trout yearlings 8,000 4,586.6
2004 Brown Trout yearlings 5,700 1,960.7
  Lake Trout yearlings 5,578 476.7
  Rainbow Trout yearlings 8,000 4,059.0

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
GRINDSTONE
Pine Co., 58012300
Bluegill Sunfish   All sizes     Mercury
Lake Trout   All sizes     Mercury
Northern Pike     All sizes   Mercury

General Population

LAKE NAME
County, DOWID
Species Meal Advice Contaminants
Unrestricted 1 meal/week 1 meal/month Do not eat
GRINDSTONE
Pine Co., 58012300
Bluegill Sunfish All sizes        
Northern Pike   All sizes     Mercury

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 07/30/2012)

Grindstone Lake, with a maximum depth of 150 feet, is unique among lakes in east central Minnesota. The long, narrow 528 acre lake has enough oxygen in its deep cold waters to support coldwater species such as trout as well as cool and warmwater species such as bass, panfish, and northern pike. Brown trout and rainbow trout are stocked annually in the spring, and additional rainbow trout are stocked in the fall. Lake trout are stocked every other year to provide one of two southern most lake trout fisheries. Rainbow smelt, which were not introduced by the DNR, provide an additional angling opportunity in winter and spring. The public access is located on an inlet on the north side of the lake. During periods of low water, boat launching can be difficult for medium to large boats.

Although Grindstone Lake is managed for trout, it is not a designated trout lake, so rules which apply to designated lakes are not in effect on Grindstone. However, a trout stamp is required to keep and transport any rainbow, brown, or lake trout. Due to Grindstone Lake's depth and steep contours, rainbow, brown, and lake trout may be difficult to locate. Winter angling is very popular and can be very productive. Open water anglers have the most success right after the May trout season opener before the surface water has warmed up and trout can still inhabit the shallower water.

Test netting in 2012 showed lower abundance of all three trout species than the 2007 netting. All brown trout netted were from the May yearling stocking, and the one rainbow trout appeared to be from the 2011 stocking. Lake trout mean size improved from the previous survey, with an average of 15.4 inches and trout up to 24 inches seen in nets. Stocked lake trout are marked by clipping one of the lower fins; only two unclipped lake trout were seen in this survey, indicating little natural reproduction.

Northern pike have consistently maintained normal population levels with above average size in Grindstone Lake. Northerns netted in 2012 had an average weight of 4.4 pounds and ranged from 18.5 to 32.6 inches. In recent years anglers have caught or speared northern pike over 40 inches.

Smallmouth bass up to 17.6 inches were captured by electrofishing, and large numbers of smaller smallmouth bass indicate good natural reproduction. Largemouth bass were sampled for the first time in 2012; the six largemouth sampled ranged from 8.5 to 20.6 inches in length. Both bass species will likely increase in abundance if the trend towards warmer summer surface water temperatures continues.

Black crappie remained above normal levels in 2012 while bluegill abundance was typical for the lake type. Most crappies exceeded 8 inches and a larger portion of the bluegill catch exceeded 7 inches than in the previous assessment.


For more information on this lake, contact:

Area Fisheries Supervisor
PO Box 398
306 Power Ave N
Hinckley, MN 55037
Phone: (320) 384-7721
Internet: Hinckley Fisheries
E-Mail: Hinckley.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 B0235 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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