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Rating depth structure for walleye.
Recent public catches load as you reach this section.
153-acre lake in Alberta. The lake tops out around 7 ft. The depth chart comes from published agency 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.
Drawn out, this is 153 acres of water rimmed by 3.2 miles of bank. The shoreline is moderately structured (index 1.8) — enough points and pockets to pattern. All of it is shallow-zone water — under ~15 ft across the entire basin, so the food chain has the run of the place. Figure 1.5 mi of water from one end to the other, 0.3 mi at the beam. You'll find it in Division No. 12. Closest neighbour on DepthScout: Lower Mann Lake, 7 mi southwest of here.
When the water first warms, yellow perch slide up into 2 to 7 ft. There's no big seasonal slide here — summer means 2 to 7 ft, winter 2 to 7 ft. Start at Shallow bay flat. It's a weed flat holding about 3 ft of water and rates prime come spring. The feeding windows run early morning. Keep a drop-shot micro plastics or a small spoon tipped with worm rigged through the warm months.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 7 ft chart-limited; documented 3 to 12 ft | midday & dawn | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 2 to 7 ft chart-limited; documented 10 to 30 ft | dawn | Deep basin (7 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 2 to 7 ft chart-limited; documented 12 to 35 ft | midday | Deep basin (7 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 2 to 7 ft chart-limited; documented 15 to 35 ft | midday & dawn | Deep basin (7 ft) | Tungsten jig + spikes, Rattle spoon (small) |
The spring pattern is a shallow one: northern pike in 2 to 7 ft. The depth story barely changes: 2 to 7 ft through summer, 2 to 7 ft in winter. The spot to know is Shallow bay flat, a weed flat in about 3 ft of water that rates prime for northern pike in spring. Plan around early morning and the evening in the warm months. Summer baits: a bucktail or a weedless spoon over cabbage gets it done.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 7 ft chart-limited; documented 2 to 8 ft | midday & dawn | Shallow bay flat (3 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 2 to 7 ft chart-limited; documented 8 to 20 ft | dawn & dusk | Shallow bay flat (3 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 2 to 7 ft chart-limited; documented 6 to 18 ft | midday & dawn | Shallow bay flat (3 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 2 to 7 ft chart-limited; documented 5 to 15 ft | midday | Shallow bay flat (3 ft) | Tip-ups, Large jigging spoon |
When the water first warms, walleye slide up into 2 to 7 ft. There's no big seasonal slide here — summer means 2 to 7 ft, winter 2 to 7 ft. If you only fish one area, make it Break off the point: a drop-off around 6 ft that scores prime in fall. In summer the feeding windows fall in the evening and early morning. Keep a crawler harness on bottom bouncer or a deep crankbait (trolled) rigged through the warm months.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 7 ft chart-limited; documented 4 to 15 ft | dusk & dawn | Main-lake point (3 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 2 to 7 ft chart-limited; documented 15 to 35 ft | dusk & dawn | Break off the point (6 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 2 to 7 ft chart-limited; documented 12 to 40 ft | dusk & night | Break off the point (6 ft) | Jigging rap, Jig + big minnow |
| Winter | 2 to 7 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (7 ft) | Jigging spoon + minnow head, Rattle bait |
Count 6 structure marks on this chart. The deepest, Deep basin, sits near 7 ft.
Season dates, license requirements, and size and bag limits for Alberta waters are set by the Alberta fishing regulations — and special regulations can apply to Grassy Island Lake specifically, so confirm the current rules before you fish.
Check the official Alberta fishing regulations →
Grassy Island Lake is about 7 ft (2 m) deep at its deepest point. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Anglers target yellow perch, northern pike, walleye on Grassy Island Lake. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Shallow bay flat is the top-rated area: a weed flat in about 3 ft of water that rates prime for yellow perch in spring. The map above holds the full rated-spot list for every 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 Grassy Island Lake is regulated by the Alberta fishing regulations. Check the official Alberta regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Lower Mann Lake 7 mi · Upper Mann Lake 9 mi · Vincent Lake 10 mi · Floatingstone Lake 10 mi · Minnie Lake 11 mi · Garner Lake 14 mi · Chickenhill Lake 16 mi · Fork Lake 18 mi · Goodfish Lake 18 mi · Moose Lake 19 mi · Bonnie Lake 21 mi · Whitefish Lake 22 mi
See how Grassy Island Lake stacks up: best walleye lakes in Alberta · best northern pike lakes in Alberta · best yellow perch lakes in Alberta
More water nearby: Division No. 12 fishing maps (45 charts). Browse all Alberta fishing maps. 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.