GLENDALOUGH STATE PARK, Minn. — As the canoe hull scraped off the sandy shore and glided off, the bottom of Annie Battle Lake fell away, ever so gradually.

Sand, more sand, then stalks of rushes piercing the bottom. The water darkened ahead, not to stained blackness, but deep azure, the color that deep water has only on the clearest, and often cleanest, of lakes.

Before the dropoff, the bottom seemed perhaps 4 to 5 feet below the surface, but I plunged my paddle straight down with a straightened arm and failed to strike. The illusion of shallowness was the result of water’s magnifying effect, which occurs only on special waters.

The bluegills that avoided the canoe’s shadow seemed extra chunky, but were they magnified, as well?

At the dropoff, cabbage weeds lined the edge and thickened as the bottom plunged into the deep blueness, to the point where only the tops of the stalks were visible, several feet below the surface.

If the anglers among you are figuratively salivating at this description, then I’ve done my job.

This lake is packed with an exceptional population of hefty crappies and bluegill, the result of the most stringent fishing regulations in the state.

But the fishing would have to wait. My canoe, laden with gear for two nights of camping, was en route to a nearby beach, where my wife, Natasha, and son, Tima, were at play.

In addition to coming here to experience what strict harvest regulations — only five sunfish and five crappies can be kept daily — this was a rehearsal for our first trip as a family to the Boundary Waters Canoe Area Wilderness.

PRISTINE LAKE

Glendalough State Park, in Otter Tail County near the town of Battle Lake (Fergus Falls is the nearest sizable city) — is among 14 Minnesota state parks at which you can boat in to a lakeshore campsite. Glendalough’s Annie Battle Lake offers three such sites, all of which can be reserved.

I can attest that, although it’s not the northwoods experience of traveling in a vast wilderness, the canoe-camping experience is legit: lakefront tranquility, private sunsets and rod, paddle and vessel only a few steps away. (My only gripe: check-in for canoe-in sites is 4 p.m., an absurdly late hour for paddlers, whose primary task is to set up before afternoon storms can brew.)

Motors are banned. In fact, a lot is banned here, which is the point. The lake is one of a few designated “heritage” lakes, where all electronics — depth finders, GPS units, underwater cameras — are banned. You fish old-school, plumbing for depths and dead-reckoning for location (with the aid of contour maps handed out at the park office).

If you’ve ever wondered what clear, sandy lakes of western Minnesota were like before cabins, piers, fertilizer runoff, motorboats and high-tech fishing pressure, come here. Relatively few do. With 55,449 visitors in 2013, Glendalough was the state’s 46th-most-visited park.

Much of the 2,761-acre park was privately owned — and not exploited — throughout its modern history. It started as a retreat in the early 1900s, then became a game farm under the ownership of F.E. Murphy, owner of the Minneapolis Tribune. When the Cowles family bought the newspaper, Glendalough Game Farm (named after an Irish monastery) came with it, and for years the progenitors of what is now the Star Tribune had a hunting retreat on some of the most attractive waterfowl real estate along the Mississippi Flyway.

That era faded, but the gem of that land — 354-acre Annie Battle Lake — never was fished heavily. In 1990, the Cowles Media Co. donated the land to the Nature Conservancy, and it was transferred to the state in 1992.

‘HERITAGE’ FISHERY

What the state inherited was a lake with fish populations that were as pristine as the water and shoreline. Translation: The fish were bigger, especially the panfish.

But their vulnerability was soon apparent. Within years after opening under standard fishing rules (30 sunnies a day), the populations began to suffer. In the late 1990s, with the support of lawmakers, Annie Battle was closed to fishing while populations recovered, and the lake was reopened as the state’s first “heritage” fishing lake.

All bass and pike must be released, and low bag limits on panfish were enacted. (For a time, an 11-inch minimum on crappies was instituted, but biologists concluded it didn’t make a difference; that was lifted several years ago.)

I’ve written about this notion that our most-taken-for-granted fish, the bluegill, needs stronger protections if the slow shrinking of sunfish size is to be stopped. Here’s a primer: tinyurl.com/BigBluegill.

Does the five-a-day rule work on Annie Battle?

The data say yes. In August 2010, Minnesota Department of Natural Resources nets on Annie Battle pulled in 86 bluegill smaller than 5 inches long and 137 between 6 and 8 inches. That’s an impressive ratio in favor of respectable sunnies. That same month, nets on Molly Stark Lake, which is connected to Annie Battle via a channel, pulled in 258 little bluegills and 175 of the bigger ones. (Focus on the ratio, not the actual numbers.) The two lakes are similar, but motorboats are allowed on Molly Stark, and it has no special fishing regulations.

Anglers say yes. When I visited in early July, I talked with angler after angler — nearly all from western Minnesota — who said they were here, either with boat or with aims to rent from the park, with panfish as their goal. Everyone I asked praised the rules, and I was struck to hear that many had no intentions of keeping their catches: a conservation ethic in the worm-and-bobber world. One neighboring campsite seemed to have a one-crappie-per-meal thing working.

“There are a lot of bass, and the walleye bite was good this year, but most people come here for the crappies and sunfish,” parks worker DeAnna Rastedt said. “You do see full stringers,” she said, but “full” is only five fish.

The fish aren’t hard to find. A small dock by the canoe-in campsites provided plenty of action for the children in our group of three families, who erected tents our first night. The rod of choice was a stick to which someone had tied a length of line. Old school.

The water was barely knee-deep. Most of those fish were small, but a few 8-inchers were taken.

Most larger sunnies have gone deeper by now, as have the crappies, and I could see other boats having success with worms. (Live bait is allowed.) Every time I tossed a Rapala behind the canoe while paddling, I caught a bass.

I’d like to confirm the panfish bite, but in truth I never had the chance. Our weekend was interrupted by a trip to an urgent-care center in Fergus Falls for what appeared to be an allergic reaction by our son, Tima, 3. Turned out to be a false alarm, but that’s another story.

The kid loved the place. He kept asking, “Why are we only staying for two nights?”

The wife loved the place. She kept asking, “Are you sure you have to tell everyone about this place?”

I do.

Dave Orrick can be reached at 651-228-5512. Follow him at twitter.com/OutdoorsNow.

IF YOU GO

What: Glendalough State Park

Where: Otter Tail County (about 200 miles northwest of St. Paul)

Why: Pristine Annie Battle Lake, big panfish

Rules: No motors, no electronics, special fishing regulations

Lodging: 22 cart-in sites, 3 canoe-in campsites, 4 camper cabins

Coming soon: 2 canoe-in/hike-in/bike-in yurts

Info: MNDNR.gov/Glendalough