Sign inSign up free Sign inSign up free Sign inSign up freeLake depth chart
Today's read
Shared by DepthScout anglers. Exact spots stay private, always.
85-acre lake in Renfrew County, Ontario. The lake tops out around 55 ft. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled. Every species below gets its seasonal read from the same numbers driving the chart.
Big Rat Lake maps at 85 acres behind 2 miles of shoreline. With a 1.5 development index there's bank structure worth casting at, in moderation. The shallow band under 15 ft claims about 89% of the surface — that's where the groceries are. Figure 0.8 mi of water from one end to the other, 0.2 mi at the beam. Renfrew County claims this one. Maskinonge Lake sits 2 mi southeast — the closest neighbouring chart.
The spring pattern is a shallow one: yellow perch in 3 to 12 ft. As the season builds they drop to 10 to 30 ft, wintering in 15 to 35 ft. Top water on the chart: Break off the point, a drop-off in the 9 ft range, prime in summer. Time it for early morning. Summer baits: a drop-shot micro plastics or a small spoon tipped with worm gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (1 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (9 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (9 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (48 ft) | Tungsten jig + spikes, Rattle spoon (small) |
When the water first warms, northern pike slide up into 2 to 8 ft. By summer they slide out to 8 to 20 ft, and by winter most fish are in 5 to 15 ft. If you only fish one area, make it Break off the point: a drop-off around 9 ft that scores prime in fall. In summer the feeding windows fall in early morning and the evening. Keep a bucktail or a weedless spoon over cabbage rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (1 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (9 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Break off the point (9 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Break off the point (9 ft) | Tip-ups, Large jigging spoon |
When the water first warms, smallmouth bass slide up into 3 to 12 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 20 to 45 ft. If you only fish one area, make it Break off the point: a drop-off around 9 ft that scores prime in fall. In summer the feeding windows fall in early morning and the evening. Keep a drop shot (goby/minnow) or a ned rig rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (1 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (9 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Break off the point (9 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (9 ft) | Blade bait, Hair jig |
Come spring, look for largemouth bass tight to the bank in 2 to 10 ft. Expect a summer slide to 8 to 20 ft, then a winter hold in 15 to 35 ft. Start at Break off the point. It's a drop-off holding about 9 ft of water and rates prime come summer. Prime time lands in early morning and the evening. A texas-rigged 10" worm or a deep-diving crankbait is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (1 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (9 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (1 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (9 ft) | Blade bait, Jigging spoon |
Start shallow in spring: rock bass sit in 2 to 10 ft that time of year. Warm water sends them out to 5 to 20 ft; cold water stacks them in 12 to 30 ft. Top water on the chart: Break off the point, a drop-off in the 9 ft range, prime in fall. Fish it in the evening and you'll meet the bite. Throw a ned rig (small) or a marabou jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Main-lake point (1 ft) | 1/16 oz jig + grub, Small inline spinner |
| Summer | 5 to 20 ft | dusk | Break off the point (9 ft) | Ned rig (small), Marabou jig |
| Fall | 8 to 22 ft | midday | Break off the point (9 ft) | Small tube jig, Inline spinner |
| Winter | 12 to 30 ft | midday | Break off the point (9 ft) | Tungsten jig + plastic, Small spoon + spike |
Start shallow in spring: pumpkinseed sit in 1 to 8 ft that time of year. Warm water sends them out to 2 to 10 ft; cold water stacks them in 6 to 18 ft. Top water on the chart: Shallow bay flat, a weed flat in the 1 ft range, prime in spring. Fish it in the evening and early morning and you'll meet the bite. Throw a micro tube or a sponge spider (fly) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 8 ft | midday & dusk | Shallow bay flat (1 ft) | Micro jig under a float, Tiny beetle-spin |
| Summer | 2 to 10 ft | dusk & dawn | Shallow bay flat (1 ft) | Micro tube, Sponge spider (fly) |
| Fall | 4 to 14 ft | dusk & dawn | Shallow bay flat (1 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 6 to 18 ft | dawn | Break off the point (9 ft) | Tungsten ice jig + plastic, Tiny spoon |
Big Rat Lake also holds brown bullhead (3 to 12 ft in summer). Pick any of them on the map above for rated spots and bait picks.
The chart marks 6 structure features on Big Rat Lake; the deepest is Deep basin at about 48 ft.
Season dates, license requirements, and size and bag limits for Ontario waters are set by the Ontario fishing regulations (FMZ summary) — and special regulations can apply to Big Rat Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Big Rat Lake is about 55 ft (17 m) deep at its deepest point. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Anglers target yellow perch, northern pike, smallmouth bass, largemouth bass, rock bass, pumpkinseed, brown bullhead on Big Rat Lake.
Shallow bay flat is the top-rated area: a weed flat in about 1 ft of water that rates prime for pumpkinseed in spring. Every other rated spot, per species and season, is on the map above.
For yellow perch, the summer bite is best in early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Big Rat Lake is regulated by the Ontario fishing regulations (FMZ summary). Check the official Ontario regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Maskinonge Lake 2 mi · Blackduck Lake 3 mi · Perch Lake 4 mi · Otterson Lake 4 mi · Corry Lake 4 mi · Sturgeon Lake 4 mi · Gwatkin Lake 5 mi · Maunsell Lake 5 mi · Thomas Lake 6 mi · Young Lake 6 mi · Kean Lake 6 mi · First James Lake 6 mi
See how Big Rat Lake stacks up: best largemouth bass lakes in Ontario · best smallmouth bass lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Renfrew County fishing maps (298 charts). Browse all Ontario fishing maps or see every water on DepthScout. Bathymetry: published agency survey data. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.