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18-acre lake in Cochrane District, Ontario. The lake tops out around 96 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. The depth data here comes from the Ontario MNRF survey of 1971, a decades-old survey (an MNRF lake survey). Here's the year, species by species, as the scoring engine sees it.
The drawn water covers 17 acres wrapped in 0.7 miles of bank. Nearly circular (index 1.2), so the story is the bottom, not the bank. About 56% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Call it 0.3 mi long. It sits in Cochrane District. Mann L. 3 sits 0 mi northeast — the closest neighbouring chart.
In spring, yellow perch run shallow here, mostly 3 to 12 ft. Midsummer fish sit out in 10 to 30 ft before dropping to 15 to 35 ft for winter. Spring yellow perch concentrate at Back-bay flat, a prime-rated feeding flat around 2 ft. Fish it in early morning and you'll meet the bite. You won't need more than a drop-shot micro plastics or a small spoon tipped with worm most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Back-bay flat (2 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shoreline break (1 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (71 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (71 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Count 4 structure marks on this chart. The deepest, Deep basin, sits near 71 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 Mann L. 4 specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Mann L. 4 is about 96 ft (29 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1971, a decades-old survey (an MNRF lake survey).
Anglers target yellow perch on Mann L. 4.
Back-bay flat is the top-rated area: a feeding flat in about 2 ft of water that rates prime for yellow perch in spring. Open the map above to see every rated spot for each species and season.
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 Mann L. 4 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.
Mann L. 3 0 mi · Mann L. 2 0 mi · Pickerel Lake 3 mi · Little Lake 4 mi · Fletchers Lake 4 mi · Devonshire Lake 6 mi · Jawbone L. 6 mi · Big Jefferson L. 6 mi · Duff L. 1 6 mi · Duff L. 2 6 mi · Jefferson Lake 6 mi · Tom Lake 7 mi
See how Mann L. 4 stacks up: best yellow perch lakes in Ontario
More water nearby: Cochrane District fishing maps (673 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.