Gem Lake Depth Map & Fishing Spots (CA)

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Lake depth chart

Gem Lake, CA

Max 80 ft

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Where to start

Callibaetis (Speckled Dun) window is on — see the hatch outlook

Hatch outlook

Callibaetis (Speckled Dun)Active window

Typical here: May 1 – Oct 1 · multi-brood; a documented midsummer lull when surface temps push fish deep

nymphthe hours before the midday emergence — nymphs rise off the weed tops in a vertical zigzag that can take hours — sources split between slow 2–4 inch strips with long pauses and a quicker steady retrieve; carry both speeds
dunmidday, roughly 11am into early afternoon
spinnermid-to-late-morning falls

Trout browse the weed-bed edges knocking nymphs loose, then cruise the flats sipping duns at midday — the marquee western lake mayfly.

The midday emergence puts cruisers over weed flats in under 20 ft: a casting bubble with a #14 Callibaetis nymph retrieved dead-slow with pauses is the honest match. Between hatch hours, small spoons and #1 inline spinners along the weed edges and drop-offs pick off the same fish.

The event happens over weed flats and weed-bed edges in 20 ft of water or less

Chironomids (stillwater midges)Active window

Typical here: Apr 25 – Oct 31 · end of April to the end of October at Crowley — the main food source for the entire season

nymphearly morning, start of the day — fish the bloodworm ON the bottom — 4–6 inches off the mud before the emergence starts
pupathe cool morning hours are prime — as the emergence builds, slide the pupa up to 12–15 inches off bottom under the indicator; a little wind chop does the jigging

Concentrates by DEPTH BAND and mud type, not a fixed spot: roughly 20–25 ft in spring, deeper midsummer, in against the feeder creeks in summer heat, 5–25 ft in fall. Match the band.

This one translates almost perfectly: a slip float with a 1/64–1/100 oz midge-pattern jig set 4–15 inches off bottom over a mud flat, dead-sticked with the chop doing the work. Depth control is everything — no moving lure imitates a hanging pupa; the float rig IS the technique.

The event happens over open mud flats alongside weedlines, channels and basin edges; feeder-creek mouths in summer heat

Grasshoppers (east-side summer)Active window

Typical here: Jul 1 – Sep 30 · the East Walker and Upper Owens terrestrial program

adultall day in high summer, best when afternoon wind knocks bugs onto the water

Pulls fish to the windward grassy banks and edges for months — fish the bank the wind blows ONTO.

The friendliest crossover of the summer: on lakes, drift the windward bank with a bubble-and-foam-hopper — the bubble's splash doesn't hurt a hopper presentation. On rivers, the same rig dead-drifted along the undercut grass banks, or small gold spinners under the banks between rises.

The event happens over grassy banks, undercut edges and windward shorelines

Next on this water

Damselfly migration · forageMay 25 – Aug 31 · in ~9 months

Recommendations come from depth structure and seasonal species behavior. Treat them as a starting point, not a guarantee. Contours on this water are approximations. Never use for navigation. Always check local regulations.

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Recent catches at Gem Lake

Shared by DepthScout anglers. Exact spots stay private, always.

No shared catches here yet — be the first.Log a catch from the map above and share it to put Gem Lake on the board.

Fishing Gem Lake: what the data says

268-acre lake near Mono County. The lake tops out around 80 ft. The contours are modeled from the water's real shoreline and maximum depth. Treat them as a rough guide, and never use them for navigation. Species by species, here's what the data says the year looks like.

The outline encloses 266 acres, worked by 4.2 miles of shoreline. A middling shoreline index (1.8) gives it some bays to work without being a maze. About 46% of the surface sits shallower than 15 ft on the modeled chart — that's the weed-and-bait zone. Call it 1.1 mi long by 0.8 mi wide at the broadest reach. It sits in Mono County. Agnew Lake sits 1 mi east — the closest neighbouring chart.

Brook Trout fishing at Gem Lake

When the water first warms, brook trout slide up into 2 to 15 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 3 to 20 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 6 ft that scores good in spring. In summer the feeding windows fall in early morning and the evening. Keep a small spoon fished deep or a trolled lake-clear wobbler + worm rigged through the warm months.

Season	Depth	Best window	Start at	Go-to baits
Spring	2 to 15 ft	dawn & dusk	Shallow bay flat (6 ft)	Small inline spinner (gold), Tiny spoon
Summer	10 to 30 ft	dawn & dusk	Break off the point (36 ft)	Small spoon fished deep, Trolled lake-clear wobbler + worm
Fall	2 to 15 ft	midday & dawn	open water	Small spoon (orange), Spinner
Winter	3 to 20 ft	dawn	Shallow bay flat (6 ft)	Small jigging spoon, Tungsten jig + plastic

Rainbow Trout fishing at Gem Lake

Come spring, look for rainbow trout tight to the bank in 5 to 20 ft. Expect a summer slide to 8 to 30 ft, then a winter hold in 8 to 40 ft. Start at Break off the point. It's a drop-off holding about 36 ft of water and rates prime come winter. Prime time lands in early morning and the evening. A dodger + spoon (deep troll) or a flutter spoon is the honest summer answer here.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Main-lake point (20 ft)	Inline spinner (silver), Small spoon
Summer	8 to 30 ft	dawn & dusk	Main-lake point (20 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	10 to 35 ft	dawn & dusk	Main-lake point (20 ft)	Casting spoon, Jerkbait over shoals
Winter	8 to 40 ft	dawn	Break off the point (36 ft)	Jigging spoon, Tube jig (white)

Notable structure

Count 6 structure marks on this chart. The deepest, Deep basin, sits near 68 ft.

Deep basin: deep basin, around 68 ft
Break off the point: drop-off, around 36 ft
Main-lake point: point, around 20 ft
Secondary point: point, around 20 ft
Shallow bay flat: weed flat, around 6 ft
Back-bay flat: weed flat, around 6 ft

Gem Lake fishing regulations

Season dates, license requirements, and size and bag limits for California waters are set by the California Department of Fish and Wildlife — and special regulations can apply to Gem Lake specifically, so confirm the current rules before you fish.

Check the official California fishing regulations →

Common questions

How deep is Gem Lake?

Gem Lake is about 80 ft (24 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.

What fish are in Gem Lake?

Anglers target brook trout, rainbow trout on Gem Lake.

Where is the best fishing spot on Gem Lake?

Break off the point is the top-rated area: a drop-off in about 36 ft of water that rates prime for rainbow trout in winter. The map above holds the full rated-spot list for every species and season.

When is the best time to fish Gem Lake?

For brook trout, the summer bite is best in early morning and the evening. 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 Gem Lake?

Fishing on Gem Lake is regulated by the California Department of Fish and Wildlife. Check the official California regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.

Nearby waters

Agnew Lake 1 mi · Waugh Reservoir 2 mi · June Lake 5 mi · Mamie Lake 13 mi · George Lake 13 mi · Mary Lake 13 mi · Tioga Lake 13 mi · Convict Lake 20 mi · Edith Lake 20 mi · Genevieve Lake 20 mi · Dorothy Lake 21 mi · Bright Dot Lake 21 mi

See how Gem Lake stacks up: best rainbow trout lakes in California · best brook trout lakes in California

More water nearby: Mono County fishing maps (9 charts). Browse all California fishing maps or 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.