Bass Lake

Where Bass Lake is

Bass Lake lies in the District Municipality of Muskoka, within the Township of Muskoka Lakes.

How deep is Bass Lake?

The deepest mapped contour on Bass Lake is 11.0 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 16 depth contours for Bass Lake.

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.

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

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.

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

Water temperature

Ontario’s aquatic resource records class Bass Lake as a cool-water lake, with a mean depth of 4.3 meters against its maximum of 11.

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 Bass 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.

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

Fish in Bass Lake

Ontario’s aquatic resource records name 7 fish species in Bass Lake.

Popular species in the province’s records

• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Rock Basssunfish
• Burbotcod
• Brown Bullheadcatfish

Stocking history

Ontario’s stocking records for Bass Lake run from 1948 to 1963 and hold 8 releases. Smallmouth Bass account for most of the fish: 9,800 released in eight of the years between 1948 and 1963. The last recorded release was 1,000 smallmouth bass fingerlings in 1963.

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

Fisheries Management Zone 15

Bass Lake lies in Fisheries Management Zone 15. Ontario sets its fishing seasons and catch limits by zone. 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.

Fisheries management zones around Bass Lake

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

Bass Lake Ice Fishing

An ice hut on Bass Lake must be removed by March 31. 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). Bass Lake lies within FMZ 15.

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 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.

Ice Out Date

The ice has been recorded leaving Bass Lake in 34 springs between 1970 and 2003. The median date is April 17. The earliest recorded break-up is March 26 in 2000, and the latest is May 4 in 1972.

Across the 34 recorded springs the date has moved earlier by about 3.3 days each decade.

The record was contributed by Martyn N. Futter to the Global Lake and River Ice Phenology Database. The record only holds the ice-out dates for Bass Lake, and no ice-in date.

Ice out dates for 34 recorded springs between 1970 and 2003

Ice conditions

No public record reports the thickness or the condition of the ice on Bass Lake 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

Nearby lakes

• Butterfly Lake6 km away
• Stewart Lake6 km away
• Lake Joseph8 km away
• Little Lake Joseph10 km away

All lakes

Questions about Bass Lake

• How deep is Bass Lake?

  Its deepest charted contour is 11 meters, and the water within it is deeper.

• How big is Bass Lake?

  Its surface covers 0.9 square kilometers, with 9 kilometers of shoreline.

• What fish are in Bass Lake?

  Ontario’s aquatic resource records name seven species, among them smallmouth bass, largemouth bass and yellow perch.