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33-acre lake near Gwynedd. The lake tops out around 154 ft. This chart interpolates between a real shoreline and a known maximum depth. It will point you at likely water, but it is not a navigation product. The season-by-season read for each species follows, from the map's own numbers.
Llyn Cau maps at 33 acres behind 1 miles of shoreline. Its 1.2 shoreline index means few bank features; the contours below do the pattern work. 8% of the surface is littoral (under ~15 ft), per the model — cover, weeds and forage water. The basin spans about 0.4 mi end to end and 0.2 mi across at its widest. Gwynedd claims this one. Its nearest charted neighbour, Llyn y Gadair, is 1 mi to the northwest.
Spring puts brown trout in skinny water — 3 to 25 ft is the zone. As the season builds they drop to 25 to 60 ft, wintering in 5 to 35 ft. Summer brown trout concentrate at Main-lake point, a prime-rated point around 39 ft. Warm-month bites cluster around after dark and early morning. A spoon at the thermocline or a deep stickbait (night) covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 25 ft | dawn & dusk | open water | Stickbait off planer boards (shallow), Small spoon along mud lines |
| Summer | 25 to 60 ft | night & dawn | Main-lake point (39 ft) | Spoon at the thermocline, Deep stickbait (night) |
| Fall | 5 to 30 ft | dusk & dawn | Main-lake point (39 ft) | Jerkbait over gravel, Casting spoon |
| Winter | 5 to 35 ft | dawn | open water | Jigging spoon, Small stickbait (slow) |
Early season european perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 8 to 28 ft, then a winter hold in 12 to 33 ft. Put Shallow bay flat first on the milk run — a feeding flat near 6 ft that grades prime for spring. In summer the feeding windows fall in early morning. Tie on a drop-shot micro plastics or a small crankbait (perch pattern) and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (6 ft) | Small jig + curly tail, Inline spinner #1-2 |
| Summer | 8 to 28 ft | dawn | Shallow bay flat (6 ft) | Drop-shot micro plastics, Small crankbait (perch pattern) |
| Fall | 10 to 33 ft | midday | open water | Jigging spoon (small), Drop-shot on deep flats |
| Winter | 12 to 33 ft | midday & dawn | open water | Tungsten jig + maggots, Small balance jig |
Come spring, look for northern pike tight to the bank in 2 to 8 ft. Expect a summer slide to 8 to 20 ft, then a winter hold in 5 to 15 ft. Start at Shallow bay flat. It's a feeding flat holding about 6 ft of water and rates prime come spring. Prime time lands in early morning and the evening. A bucktail or a weedless spoon over cabbage is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (6 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (6 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (6 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (6 ft) | Tip-ups, Large jigging spoon |
The spring pattern is a shallow one: arctic char in 4 to 15 ft. Midsummer fish sit out in 20 to 60 ft before dropping to 10 to 40 ft for winter. The spot to know is Break off the point, a drop-off in about 69 ft of water that rates prime for arctic char in summer. Plan around early morning in the warm months. Summer baits: a jigging spoon vertical or a tube jig (smelt) gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | midday & dawn | Shallow bay flat (6 ft) | Small casting spoon (silver/orange), Jerkbait (small) |
| Summer | 20 to 60 ft | dawn | Break off the point (69 ft) | Jigging spoon vertical, Tube jig (smelt) |
| Fall | 8 to 30 ft | midday & dusk | open water | Casting spoon (orange/gold), Beadhead streamer |
| Winter | 10 to 40 ft | midday & dawn | open water | Jigging spoon (glow/silver), Tungsten jig + plastic |
Structure-wise the chart holds 4 features, led in depth by Deep basin at roughly 131 ft.
Llyn Cau is about 154 ft (47 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target brown trout, european perch, northern pike, arctic char on Llyn Cau. 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 feeding flat in about 6 ft of water that rates prime for european perch in spring. Every other rated spot, per species and season, is on the map above.
For brown trout, the summer bite is best in after dark and early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Llyn y Gadair 1 mi · Tal-y-llyn Lake 1 mi · Llyn Gwernan 2 mi · Llyn Cwm-mynach 7 mi · Llyn Erddyn 8 mi · Llyn Dulyn 8 mi · Llyn Bodlyn 8 mi · Llyn Glanmerin 9 mi · Llyn y Bi 9 mi · Llyn Hywel 9 mi · Gloyw Lyn 12 mi · Llyn Penrhaeadr 12 mi
See how Llyn Cau stacks up: best northern pike lakes in United Kingdom · best european perch lakes in United Kingdom · best brown trout lakes in United Kingdom · best arctic char lakes in United Kingdom
More water nearby: Gwynedd fishing maps (35 charts). Browse all United Kingdom fishing maps. See every water on DepthScout. 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.