Trout Lake

Where Trout Lake is

Trout Lake lies in the District of Nipissing, with shoreline in the City of North Bay and the Township of East Ferris.

How deep is Trout Lake?

The deepest mapped contour on Trout Lake is 67.1 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 91 depth contours for Trout 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.

Trout Lake has 20 Lake Partner monitoring sites. Nineteen have reported phosphorus for the three or more years the province requires before a status is assigned. All are classified oligotrophic.

The longest record is held by site 5455/1 at Delaney Bay, TL1, sampled over 13 springs to 2025. Its long-term mean phosphorus concentration is 3.97 micrograms per litre, within the oligotrophic band, which extends to 10. The site’s 53 clarity readings give a median Secchi depth of 5.4 meters.

Water temperature

Ontario’s aquatic resource records class Trout Lake as a cold-water lake, with a mean depth of 16.9 meters against its maximum of 67.1.

A deep lake separates into layers through the summer. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold through the whole season. A mean depth of 16.9 meters places most of Trout Lake’s volume in that cold layer, which is the condition lake trout and lake whitefish require.

No provincial monitoring station records water temperature on Trout 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 Trout 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 Trout Lake

Ontario’s aquatic resource records name 29 fish species in Trout Lake. The province classes the lake as cold water. The record took effect on 8 January 2018, and it compiles what field biologists had reported by then.

Fifteen of the 29 species in the province’s records

• Lake Trouttrout and whitefish
• Brook Trouttrout and whitefish
• Rainbow Trouttrout and whitefish
• Ciscotrout and whitefish
• Atlantic Salmontrout and whitefish
• Northern Pikepike
• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Burbotcod

Spawning areas

Ontario maps 2 fish spawning records within the Trout Lake outline: 2 lake trout spawning areas covering 1.47 hectares.

By number of records

By area mapped

• Lake Trout2 areas1.5 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 Trout Lake run from 1946 to 1994 and hold 76 releases. Walleye account for most of the fish: 856,092 released in six of the years between 1946 and 1990. The last recorded release was 2,000 atlantic salmon yearlings in 1994.

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

Eating the fish

The 2025 Guide to Eating Ontario Fish carries consumption advice for seven species taken from Trout Lake, tested for contaminants at a sampling location in east of North Bay, E. Ferris & Widdifield Twps. 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 11

Trout Lake lies in Fisheries Management Zone 11. Ontario sets its fishing seasons and catch limits by zone.

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.

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

Trout Lake Ice Fishing

An ice hut on Trout Lake must be removed by March 31. Trout Lake lies in fisheries management zone 11, 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 11 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 comes and goes

Ice has been recorded on Trout Lake in 24 winters between 1956 and 1988. The median date of complete ice cover is December 17 and the median date of complete ice loss is April 28, a median season of 135 days.

The longest recorded season is 144 days in 1971-72, and the shortest is 120 days in 1987-88.

The record was contributed by W. R. Skinner, Environment Canada to the Global Lake and River Ice Phenology Database, and the ice was read at a weather station rather than from the middle of the lake. Observations were last contributed for 1988, and none have been added since.

Ice conditions

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

Islands and names

Trout Lake contains 26 islands in the Ontario Hydro Network’s outline, three of them over 10 hectares and six under a tenth of a hectare.

Official names

Ontario’s geographic names register lists 25 official names on the water and its islands: 19 islands and five bays. A further 2 named points stand on the mainland shore.

Bays 5

• Delaney Bay
• Dugas Bay
• Four Mile Bay
• Milnes Bay
• One Mile Bay

Points on the shore 2

• Doran Point
• Pilot Point

Nearby lakes

• Turtle Lake12 km away
• Lake Nosbonsing15 km away
• Lake Talon20 km away
• Lake Nipissing45 km away

All lakes

Questions about Trout Lake

• How deep is Trout Lake?

  Its deepest charted contour is 67.1 meters, and the water within it is deeper.

• How big is Trout Lake?

  Its surface covers 18.9 square kilometers and it holds 26 islands. Of its 73 kilometers of shoreline, 57 kilometers is the mainland shore and 16 kilometers is the shore of the islands.

• What fish are in Trout Lake?

  Ontario’s aquatic resource records name 29 species, among them lake trout, walleye, smallmouth bass, largemouth bass, northern pike and muskellunge.

• Is the water clear?

  All nineteen monitoring sites with a phosphorus status are classified oligotrophic, the clearest of the province’s three bands.