The Washington Suburban Sanitary Commission will assign boat mooring stakes for its Triadelphia and Rocky Gorge reservoirs at 7:30 a.m. Saturday. Stakes will be awarded on a first-come, first-served basis at the Jewell Visitors Center above Brighton Dam.

Fishing/boating season opens at the two big impoundments March 1. Anyone seeking a stake must buy a $30 season-use permit. Call (301) 699-4172.


Anglers Unlimited will hold its 16th annual fresh- and saltwater fishing show from 10 a.m. to 4 p.m. today at Martin's Crosswinds in Greenbelt, with tackle on sale and seminars by guides and charter skippers. Admission $4, kids free. For details, call Art Cousin, (301) 474-7426.

Also, the Potomac-Patuxent Chapter of Trout Unlimited will offer a slide show by Alaska guide Barry Johnson at its monthly meeting, 7:30 p.m. Thursday at Glenallan Elementary School, 125 Heurich Rd., Silver Spring. Public is welcome. Call (301) 384-0424.

And Saltwater Sportsman magazine's all-day national fishing seminar rolls into Annapolis, 9 a.m. to 4 p.m. Saturday at Maryland Hall for the Creative Arts, with talks by local and national tidewater fishing experts. Admission of $30 includes a 100-page textbook. Call 1-800-448-7360.


It seems too early for this sort of thing, but the headboat Miss Ocean City scheduled its first foray into the Atlantic this weekend to hunt for migrating Boston mackerel.

Usually, mackerel fishing doesn't start off the Maryland coast until early in April, but last year there was a fantastic run off Virginia Beach starting in January, and already this year Ocean City's commercial netters have been loading up on mackerel outside the Jackspot, 30 miles off the beach. Adventurous? Call the Miss Ocean City at (301) 289-8234 and find out how they did.


Maryland has strict new regulations for personal watercraft, those annoying jet-ski contraptions that buzz around the water all summer. The new rules ban wake-jumping, require operators to wear life jackets, set a minimum age of 14 for operators, limit speed to 6 knots within 100 feet of a vessel, shore, wharf, pier, piling, bridge or abutment, and ban night operation or towing skiers.


Northern Virginia Chapter of Trout Unlimited offers two, six-week fly-fishing courses. The first session will start Feb. 27 and will run five Wednesday nights at the National Wildlife Federation Center on Rte. 7, west of the Beltway. Final class on casting techniques will be on a Saturday morning at Wolf Trap. The second session will start April 10. Cost will be $40 for TU members, $60 for nonmembers; equipment provided. Call (703) 494-9741.


Cruising sailors John Neal and Barbara Marrett will present their "Paradise Landfalls" lecture 7:30-10:30 p.m. Thursday at St. John's College in Annapolis. Neal, author of a delightful account of his South Pacific wanderings called "Log of the Mahina," has logged more than 100,000 miles at sea in small boats. Tickets are $10 and should be available at the door, or can be ordered by phone at (401) 847-1588.


The Northern Virginia Planning District Commission has a new map showing all local, regional, state and federal parks in the region. For a copy, send $5 to the agency at 7535 Little River Turnpike, Suite 100, Annandale, Va. 22003, or call (703) 642-0700.


The National Ocean Access Project, a nonprofit organization that provides recreational marine opportunities for the disabled, is looking for members and sponsors for the 1991 season. NOAP has a fleet of four, specially equipped 20-foot sloops to take the disabled sailing and organizes diving, swimming and other water-related activities. For information, call (301) 280-0604.