Head Lake

Where Head Lake is

Head Lake lies in the County of Haliburton, within the Municipality of Dysart Et Al.

How deep is Head Lake?

The deepest mapped contour on Head Lake is 4.6 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 4 depth contours for Head Lake.

Surveyed Depths

Ontario has surveyed the depths of several thousand of its lakes over more than half a century. Later surveys were conducted by boat with satellite positioning and produced hundreds of thousands of soundings per lake. Earlier surveys were charted by running transects across the water and drawing depth contours by hand.

Water quality

Ontario’s Lake Partner Program is a volunteer monitoring network. Participants collect a water sample each spring for phosphorus analysis and measure water clarity through the summer with a Secchi disk.

Phosphorus is the nutrient that controls how much algae a lake can grow. A lake with little phosphorus stays clear and supports cold-water fish such as lake trout. As phosphorus rises, algae increase, the water clouds, and oxygen in the deep water falls as the algae decay. The province classifies each monitoring site by its spring phosphorus. Below 10 micrograms per litre is oligotrophic: clear water and low algae. From 10 to 20 is mesotrophic: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom. Above 20 is eutrophic: nutrient-rich water, prone to algal blooms and low oxygen at depth.

A Secchi disk is a 20 centimeter white or black-and-white plate lowered on a marked line until it disappears from view. The depth at which it vanishes is the Secchi depth, a direct measure of water clarity. Clearer water gives a deeper reading.

Head Lake has 1 Lake Partner monitoring site, which has yet reported phosphorus for the three years the province requires before a status is assigned.

Water temperature

Ontario’s aquatic resource records class Head Lake as a cool-water lake.

A lake separates into layers through the summer where it is deep enough. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold. A shallow lake mixes to the bottom instead and warms through, sooner in spring and later into autumn.

No provincial monitoring station records water temperature on Head Lake. The province’s longest in-water record is kept on eight research lakes near Dorset, sampled since 1976. A reading is taken at the surface, at one meter, at each meter to seven and then every two meters to the bottom, about every two weeks through the open-water season and about monthly under ice. The record holds 5,240 readings at a depth of one meter.

At one meter the eight lakes track one another closely. On a day when several were sampled, the warmest and the coolest lake differed by about one degree in every month of the year, and a 12 meter deep lake and a 37 meter deep lake read within 0.2 degrees of each other from June to October. The weather of the year, and not the lake, sets most of the width of the band below.

Satellite thermal imagery gives a surface reading on clear days: the Landsat sensors pass over Head Lake every eight days at a resolution of 100 meters. In the province’s record the surface reading and the one meter reading agree to within half a degree nine times in ten in summer.

The water a few meters down is colder than any figure on this chart, in every month of the year.

How depth changes the temperature

The chart below is the province’s record on Harp Lake, 37 meters deep, drawn as the median temperature at each depth for each month over 49 years. In July the water at one meter is 23 degrees, at five meters 15, at seven meters 9, and from 13 meters to the bottom under 6. By October the warm layer has deepened to seven meters and cooled to 11 degrees. In February the whole column sits between 1 and 4 degrees under the ice, coldest at the top.

A shallower lake in the same record warms sooner. Heney Lake, six meters deep, reads about 1.8 degrees warmer than Harp Lake at one meter from January to May, 0.8 degrees warmer from June to August, and the same or cooler from September.

Fish in Head Lake

Ontario’s aquatic resource records name 9 fish species in Head Lake. The province classes the lake as cool water. The record took effect on 11 June 2021, and it compiles what field biologists had reported by then.

Eight of the nine species in the province’s records

• Ciscotrout and whitefish
• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Pumpkinseedsunfish

Spawning areas

Ontario maps 9 fish spawning records within the Head Lake outline, for three species, all of them mapped areas.

By number of records

By area mapped

• Largemouth Bass4 areas0.6 ha
• Muskellunge3 areas0.3 ha
• Walleye2 areas0.7 ha

The federal Fisheries Act prohibits the harmful alteration, disruption or destruction of fish habitat without an authorization, so a dock, dredging, infill or shoreline work at a mapped spawning area is reviewed on that basis.

Stocking history

Ontario’s stocking records for Head Lake run from 1946 to 2015 and hold 27 releases. Walleye account for most of the fish: 1,089,275 released in eleven of the years between 1962 and 2015. The last recorded release was 220,000 walleye frys in 2015.

The province’s current stocking programme, recorded from 2016, lists no release into Head Lake.

Eating the fish

The 2025 Guide to Eating Ontario Fish carries consumption advice for one species taken from Head Lake, tested for contaminants at a sampling location in Dysart Twp., Haliburton Co. Each figure below is the most meals a month the guide advises for a fish of that length. The advice falls as the fish gets longer, because mercury accumulates over a fish’s life. A zero means the guide advises no meals of that fish at that size.

General population adultsSensitive population children under fifteen, women who are or may become pregnant

Fisheries Management Zone 15

Head Lake lies in Fisheries Management Zone 15. Ontario sets its fishing seasons and catch limits by zone. Zone 15 covers central Ontario from Georgian Bay to the Ottawa River, bounded to the north by the Pickerel River, Highway 522 and the northern edge of Algonquin Park. It takes in Parry Sound, Huntsville, Bracebridge, Bancroft, Pembroke and Renfrew, and the whole of Algonquin Provincial Park. The province describes it as a zone of many natural lake trout and brook trout lakes, with a well-developed road network and moderate angling effort.

The figures are the number of fish an angler may catch and keep in a day and have in possession, under a sport fishing licence and under a conservation licence. The rows are the whole zone’s, and they apply to every lake in it. No waterbody exception names Head Lake.

Head Lake Ice Fishing

An ice hut on Head Lake must be removed by March 31. Head Lake lies in fisheries management zone 15, one of the twenty zones Ontario sets its fishing rules by, and one removal date applies across the whole zone.

An ice hut must also be removed before the ice breaks up, whether or not that date has passed. The deadline clears huts from the ice ahead of the thaw and does not close the fishing season.

Registration is required in zone 15 for an ice hut built of anything other than fabric, and for a fabric tent covering seven square meters or more. Registration is free, and the number is displayed on the outside of the hut.

When the ice goes out

The ice has been recorded leaving Head Lake in 99 springs between 1900 and 2001. The median date is April 20. The earliest recorded break-up is March 28 in 1945, and the latest is May 5 in 1904.

Across the 99 recorded springs the median date has moved by less than a day each decade.

The record was contributed by Peter J. Dillon, Ontario Ministry of the Environment to the Global Lake and River Ice Phenology Database. It holds the day the ice left and carries a freeze date for only six of those winters, too few to draw on, so it says nothing about when Head Lake freezes.

Ice conditions

No public record reports the thickness or the condition of the ice on Head Lake on any given day. Ontario publishes ice safety guidance for anyone going out on the ice, at ontario.ca.

Nearby lakes

• Soyers Lake8 km away
• Kashagawigamog Lake8 km away
• Drag Lake9 km away
• Eagle Lake10 km away

All lakes

Questions about Head Lake

• How deep is Head Lake?

  Its deepest charted contour is 4.6 meters, and the water within it is deeper.

• How big is Head Lake?

  Its surface covers 0.7 square kilometers, with 5 kilometers of shoreline.

• What fish are in Head Lake?

  Ontario’s aquatic resource records name nine species, among them walleye, smallmouth bass, largemouth bass, muskellunge, yellow perch and black crappie.