Baptiste Lake

Where Baptiste Lake is

Baptiste Lake lies in the County of Hastings, within the Municipality of Hastings Highlands.

How deep is Baptiste Lake?

The deepest mapped contour on Baptiste Lake is 30.5 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 42 depth contours for Baptiste 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.

Baptiste Lake has 5 Lake Partner monitoring sites. Two have reported phosphorus for the three or more years the province requires before a status is assigned. One of those sites is classified oligotrophic and one mesotrophic.

The longest record is held by site 196/2 at Lavallee Bay, with phosphorus sampled once a year over 21 years to 2025. Its long-term mean phosphorus concentration is 15.52 micrograms per litre, within the mesotrophic band, which runs from 10 to 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 184 clarity readings at site 196/2 give a median Secchi depth of 4.0 meters.

Median Secchi depth by year at site 196/2

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

Baptiste Lake Weather

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

Baptiste Lake weather

Water temperature

Ontario’s aquatic resource records class Baptiste Lake as a cold-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 Baptiste Lake. The weather page for Baptiste Lake 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

Fish in Baptiste Lake

Ontario’s aquatic resource records name 20 fish species in Baptiste Lake.

Popular species in the province’s records

• Lake Trouttrout and whitefish
• Lake Whitefishtrout and whitefish
• Ciscotrout and whitefish
• Northern Pikepike
• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Burbotcod
• Brown Bullheadcatfish

Spawning areas

Ontario maps 30 fish spawning records within the Baptiste Lake outline, for five different species, and all of them are mapped below.

By number of records

By area mapped

• Walleye13 areas5.1 ha
• Muskellunge8 areas10.4 ha
• Lake Trout7 areas800 m²
• White Sucker1 area700 m²
• Lake Whitefish1 area4.7 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 Baptiste Lake run from 1946 to 1986 and hold 53 releases. Walleye account for most of the fish: 6,050,000 released in eight of the years between 1946 and 1954. The last recorded release was 20,000 muskellunge frys in 1986.

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

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for nine species taken from Baptiste Lake, tested for contaminants at a sampling location in Herschel Twp., Hastings Co. 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 15

Baptiste 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 Baptiste Lake

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

Baptiste Lake Ice Fishing

An ice hut on Baptiste 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). Baptiste 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 In / Out Date

No ice record is kept on Baptiste Lake. The province’s nearest long record covers eight lakes near Dorset, about 74 kilometers away. It holds a date for every winter since 1975, observed by eye and from cameras set on the shore.

On those eight lakes the median date of complete ice cover is December 7 and the median date of complete ice loss is April 20, a median season of 134 days.

The date the ice forms has moved later through the record: a November 26 average across 1971 to 1980, and December 11 across 2011 to 2020. The date it leaves has moved by less than a day each decade over the same period. The two charts below are drawn to one scale of 26 days, so they can be read against each other.

Ice in date (eight lakes near Dorset, ON)

Ice out date (eight lakes near Dorset, ON)

Ice conditions

No public record reports the thickness or the condition of the ice on Baptiste 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 and When the Lakes Will Freeze This Winter

Islands and names

Baptiste Lake contains 23 islands in the Ontario Hydro Network’s outline, one of them over 10 hectares and seven under a tenth of a hectare. Three of them lie mostly inside wetland the province’s Wetland With Significance dataset maps as unclassified wetland.

Official names

Ontario’s geographic names register lists 5 official names on the water and its islands: four bays.

Bays 4

• Dog Bay
• Hay Bay
• Lavalley Bay
• Redmond Bay

Nearby lakes

• Paudash Lake18 km away
• Lake St. Peter21 km away
• Esson Lake23 km away
• Miskwabi Lake27 km away

All lakes

Questions about Baptiste Lake

• How deep is Baptiste Lake?

  Its deepest charted contour is 30.5 meters, and the water within it is deeper.

• How big is Baptiste Lake?

  Its surface covers 22.3 square kilometers and it holds 23 islands. Of its 117 kilometers of shoreline, 106 kilometers is the mainland shore and 11 kilometers is the shore of the islands.

• What fish are in Baptiste Lake?

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