Lake Scugog

Where Lake Scugog is

Lake Scugog lies in the Regional Municipality of Durham, with shoreline in the Township of Scugog and the City of Kawartha Lakes.

How deep is Lake Scugog?

The deepest mapped contour on Lake Scugog is 6.1 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 7 depth contours for Lake Scugog.

See also Ontario's Largest and Deepest Lakes

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 water samples for phosphorus analysis and measure water clarity through the summer with a Secchi disk. Most sites are sampled for phosphorus once a year, in spring, and some several times a year between spring and fall. Phosphorus in many lakes rises through the summer, so the two kinds of average are measured on different bases.

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 average phosphorus:

• Oligotrophic, below 10 micrograms per litre: clear water and low algae.
• Mesotrophic, from 10 to 20: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom.
• Eutrophic, above 20: nutrient-rich water, prone to algal blooms and low oxygen at depth.

Lake Scugog has 10 Lake Partner monitoring sites. Six have reported phosphorus for the three or more years the province requires before a status is assigned. Two of those sites are classified mesotrophic and four eutrophic.

The longest record is held by site 6922/12 at Viewlake-deep spot, with phosphorus sampled several times a year between spring and fall over 16 years to 2025. Its long-term mean phosphorus concentration is 22.55 micrograms per litre, within the eutrophic band, which begins at 20.

A Secchi disk is a 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.

The 93 clarity readings at site 6922/12 give a median Secchi depth of 0.9 meters.

Median Secchi depth by year at site 6922/12

See also Lake Water Quality and Blue-Green Algae in Ontario

Lake Scugog Weather

The weather page for Lake Scugog carries the forecast over the water, wave heights across the lake, the modelled water temperature, and the water level.

Lake Scugog weather

Water temperature

Ontario’s aquatic resource records class Lake Scugog as a warm-water lake, with a mean depth of 1.37 meters against its maximum of 6.1.

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 Lake Scugog. The weather page for Lake Scugog carries the LastLake model’s surface water temperature for each day of the coming week. 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.

Water temperature at a depth of one meter (eight lakes near Dorset, ON)

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.

See also Lake Water Temperature in Ontario

Lake Scugog Water Level

Parks Canada measures the level of Lake Scugog at a gauge on the lake, on the Trent-Severn Waterway, and posts one reading each weekday. The record below holds every reading since 1 January 2026, set against Parks Canada’s average, highest and lowest level for each day of the year.

Readings are provisional, posted by Parks Canada on weekdays, and are not intended for flood warning.

Fish in Lake Scugog

Ontario’s aquatic resource records name 41 fish species in Lake Scugog. The province’s other records for the lake name one further species, brook trout. It appears in the records below.

Popular species in the province’s records

• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Brown Bullheadcatfish
• Common Carpminnow
• Lake Sturgeonother

Spawning areas

Ontario maps 72 fish spawning records within the Lake Scugog outline, for four different species, and all of them are mapped below.

By number of records

By area mapped

• Largemouth Bass25 areas16.5 ha
• Muskellunge23 areas25.4 ha
• Smallmouth Bass12 areas12.1 ha
• Walleye12 areas9.3 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 Lake Scugog run from 1946 to 1989 and hold 94 releases. Muskellunge account for most of the fish: 2,228,450 released in 34 of the years between 1946 and 1989. The last recorded release was 1,950 muskellunge fingerlings in 1989.

The province’s record of stocking for recreational fishing, kept from 2016, lists no release into Lake Scugog.

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for twelve species taken from Lake Scugog, tested for contaminants at a sampling location in Durham R.M. Each figure below is the most meals a month the guide advises for a fish of that length. Where mercury sets the advice, the figure falls as the fish gets longer, because mercury accumulates over a fish’s life. Where the guide has no result yet for certain contaminants at a location, it sets a precautionary limit of 16 meals a month. 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 17

Lake Scugog lies in Fisheries Management Zone 17. Ontario sets its fishing seasons and catch limits by zone.

Fisheries management zones around Lake Scugog

Where a row reads zone-wide, the zone’s own season or limit above applies.

See also Fishing Seasons in Ontario, Zone by Zone and Fish Stocking in Ontario Lakes

Lake Scugog Ice Fishing

An ice hut on Lake Scugog must be removed by March 1. The province sets dates for ice hut removal as a safety measure to ensure huts are removed before thawing occurs. One date applies to an entire fisheries management zone (FMZ). Lake Scugog lies within FMZ 17.

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 FMZ 17 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.

Ice Out Date

The ice has been recorded leaving Lake Scugog in 93 springs between 1901 and 1995. The median date is April 11. The earliest recorded break-up is March 15 in 1983, and the latest is April 29 in 1904 and 1972.

Across the 93 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. The record only holds the ice-out dates for Lake Scugog, and no ice-in date.

Ice out dates for 93 recorded springs between 1901 and 1995

Ice conditions

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

See also Lake Ice in Ontario and When the Lakes Will Freeze This Winter

Islands and names

Lake Scugog contains eighteen islands in the Ontario Hydro Network’s outline, one of them over 10 hectares and twelve under a tenth of a hectare. Nine of them lie mostly inside wetland the province’s Wetland With Significance dataset maps as marsh, open water or unclassified wetland. The largest of these, at 17.5 hectares, falls inside the Lake Scugog Marsh (Osler Marsh).

The province’s register names five further islands on Lake Scugog, which the outline draws joined to the shore: Scugog Island, Washburn Island, Seven Mile Island, Platten Island and Birch Island.

Official names

Ontario’s geographic names register lists 2 official names on the water and its islands: two bays. A further 6 named points stand on the shore.

Bays 2

• King's Bay
• Starr Bay

Points on the shore 6

• Ball Point
• Pine Point
• Plum Point
• Scugog Point
• Stephenson Point
• Williams Point

Nearby lakes

• Sturgeon Lake33 km away
• Cameron Lake41 km away
• Pigeon Lake43 km away
• Mitchell Lake44 km away

All lakes

Questions about Lake Scugog

• How deep is Lake Scugog?

  Its deepest charted contour is 6.1 meters, and the water within it is deeper.

• How big is Lake Scugog?

  Its surface covers 66.5 square kilometers and it holds 18 islands. Of its 155 kilometers of shoreline, 149 kilometers is the mainland shore and 6 kilometers is the shore of the islands.

• What fish are in Lake Scugog?

  Ontario’s aquatic resource records name 41 species, among them walleye, smallmouth bass, largemouth bass, muskellunge, yellow perch and black crappie. The lake’s spawning, consumption and stocking records also name brook trout.