Mann L. 3 Depth Map & Fishing Spots (ON)

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Lake depth chart

Mann L. 3, ON

Max 45 ft

Today's read

Where to start

Fall shiner run window is on — see the hatch outlook

Hatch outlook

Fall shiner runActive window

Typical here: Sep 1 – Oct 31 · same push on the Ontario side — Simcoe's shiners migrate shallow as the water cools, and the predators ride with them

adultdaylight for the jig bite; after dark the shiners stack under dock lights with walleyes and pike mixed right in — follow the bait, not the spot — millions of shiners move together and the predators ride with them; silver profile and flash matter

Concentrates hard but travels — the school (and the walleyes under it) can be off a river mouth one week and miles upriver the next.

Jig-and-minnow is the event's signature — a frozen emerald shiner on a 1/4 oz jig drifted along the run; silver jerkbaits and trolled crankbaits take the roaming fish; blade baits under the schools.

The event happens over river mouths and the first miles upriver, warming shallow shorelines, and rocky points where the displaced bait stacks

Next on this water

Hex (giant mayfly) · mayflyMay 25 – Aug 10 · in ~9 months

June mayfly hatch (walleye lakes) · mayflyJun 1 – Aug 10 · in ~9 months

Recommendations come from depth structure and seasonal species behavior. Treat them as a starting point, not a guarantee. Contours here are generated from real agency depth surveys; use the survey badge for the provider, dataset, datum and measured coverage. Never use for navigation. Always check local regulations.

Depth · ft

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Recent catches at Mann L. 3

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Fishing Mann L. 3: what the data says

16-acre lake in Cochrane District, Ontario. The lake tops out around 45 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). The season-by-season read for each species follows, from the map's own numbers.

On the chart, Mann L. 3 draws 16 acres inside 0.8 miles of shoreline. Index 1.5 on the shoreline: a few honest points and pockets, nothing labyrinthine. Littoral water — the productive band under ~15 ft — makes up 86% of this chart. Tip to tip the water measures near 0.3 mi with a 0.2-mi widest point. The water lies in Cochrane District. The nearest mapped water is Mann L. 2, 0 mi to the northwest.

Yellow Perch fishing at Mann L. 3

Spring yellow perch on Mann L. 3 hold shallow, usually 3 to 12 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 15 to 35 ft. The chart's best answer is Deep basin — deep basin, 37 ft, prime for fall. Prime time lands in early morning. The summer box starts with a drop-shot micro plastics or a small spoon tipped with worm.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 12 ft	midday & dawn	open water	Small jig + curly tail, Perch-pattern micro crank
Summer	10 to 30 ft	dawn	Deep basin (37 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	12 to 35 ft	midday	Deep basin (37 ft)	Jigging spoon (small), Perch rig / spreader
Winter	15 to 35 ft	midday & dawn	Deep basin (37 ft)	Tungsten jig + spikes, Rattle spoon (small)

Notable structure

Mann L. 3 carries 3 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 37 ft down.

Deep basin: deep basin, around 37 ft
Main-lake point: point, around 1 ft
Break off the point: drop-off, around 1 ft

Mann L. 3 fishing regulations

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. 3 specifically, so confirm the current rules before you fish.

Check the official Ontario fishing regulations →

Common questions

How deep is Mann L. 3?

Mann L. 3 is about 45 ft (14 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).

What fish are in Mann L. 3?

Anglers target yellow perch on Mann L. 3.

Where is the best fishing spot on Mann L. 3?

Deep basin is the top-rated area: a deep basin in about 37 ft of water that rates prime for yellow perch in fall. The interactive chart above rates every spot for each species and season.

When is the best time to fish Mann L. 3?

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.

What are the fishing regulations for Mann L. 3?

Fishing on Mann L. 3 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.

Nearby waters

Mann L. 2 0 mi · Mann L. 4 0 mi · Pickerel Lake 4 mi · Little Lake 4 mi · Fletchers Lake 4 mi · Devonshire Lake 6 mi · Big Jefferson L. 6 mi · Tom Lake 6 mi · Jeannie Lake 6 mi · Jefferson Lake 6 mi · Jawbone L. 6 mi · Mary Lake 6 mi

See how Mann L. 3 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.