FOR a couple of days each year, Alaska fishermen are hit by storms and floods.The storms, they say, come inevitably on the days designated months in advance by the International Pacific Halibut Commission (IPHC) as the year's two or three 24-hour Alaska commercial halibut seasons. The floods are what happen to markets that are saturated with halibut caught at the same time by up to 6,000 vessels plying Alaskan waters. The oversupply, fishermen complain, plus the need to freeze most of the fish flood, depresses prices they receive for their catch. One of the world's most frenzied food harvests, the Alaska halibut fishery supplies nearly all of this white fish prized by chefs and supermarkets. In 1990, 52.9 million pounds of Pacific halibut were caught commercially in Alaskan waters, compared to 8.5 million pounds off British Columbia and 324,000 pounds off Washington, Oregon, and California, according to the Seattle-based IPHC. This month's 24-hour opening from noon Sept. 3 to noon Sept. 4 brought a harvest of 23.7 million pounds of halibut. Concerned about exceeding Alaska's total season quota, the IPHC said last week that there would be no more openings this year. This year's only other Alaska commercial halibut opening was held May 7. The system must change, fishermen here say. They complain that the compressed fishing season, open to nearly everyone with a boat and enough cash to pay the small license fee, gives fishermen no alternative but to venture out in bad weather, forego sleep and safety precautions, and to harvest halibut hurriedly and often carelessly. "I'm getting too old for these 24-hour openings. It's rough on your body," said Robert Thomassen, a 47-year-old captain from Petersburg, Alaska, as he stood on the dock here in the driving rain that blew in from the Gulf of Alaska, fishing grounds for the Seward-based fleet. Like others, he joked that the Alaska weather always turns bad at the start of halibut openings. The recent opening was no exception. After days of sunny, clear and calm weather, gale force winds and rain greeted the halibut fishermen. The winds and choppy seas pinned many of the smaller vessels close to shore and away from the fish. Even fishermen who hauled in good harvests expressed dissatisfaction with the prices. While Alaskan halibut fetched $1.60 to $2.35 a pound from processors last week, British Columbian halibut caught under a different system brings about $3 a pound, fisheries officials said. Thanks to a quota system started this year, the Canadian fish can be handled more gently and supplied fresh for months to markets, fisheries officials said. Now the North Pacific Fishery Management Council, the group that regulates fishery management in federal waters off Alaska's coasts, is considering changing the system here to one resembling Canada's program. A proposal to divvy up the catch by individual quotas, limiting entry to those with past participation in the fishery, is on the agenda for the council's meeting starting today. The flood of new entrants with bigger boats into the now wide-open halibut fishery has squeezed the harvests down to the two or three 24-hour openings from the 122-day season 12 years ago, notes Clem Tillion, a North Pacific council member and onetime halibut fishermen spearheading the quota campaign. "You have one pie and everybody has a right to a slice, and pretty soon your slice gets pretty thin." Mr. Tillion expects fierce opposition from fishermen who prefer the open-access system that, although risky, gives part-time mariners a chance to earn $10,000 or $20,000 for a day's fishing. "They like the lottery, the excitement," Tillion says. "What you're looking at is the end of the frontier." Just how officials should limit entry into this wide-open fishery remains a matter of debate. Defenders of the current system fear that processors will use their own boats to dominate the market. The limited entry proposal also poses administrative challenges, such as enforcing catch limits on permit-holders who would have an incentive to underreport their harvests. This year, fishermen who suffered through a season of dismal salmon prices pinned their hopes on a halibut windfall. Many returned to the Seward docks nearly empty-handed and angry at the current system, however. Even the successful halibut fishermen here argued for limited entry. Chuck Kissell of Coos Bay, Ore., was one of five crew members who worked on a big 85-foot vessel on the Gulf of Alaska and hauled in 50,000 pounds of halibut and about $6,000 each. But he is buying a small boat that could never have endured the rough weather of the last opening, he says. He scoffs at the oft-repeated legend of part-time halibut fishermen bringing home a fortune for 24 hours of work. "I think the glory days of the past are pretty much exaggerated," he says. For the US Coast Guard, the current derby-style halibut harvest poses problems. "When they do have these halibut openings, it's like a mad rush to get out there," agency spokesman Ed Moreth says. As usual, the Coast Guard was swamped with mayday calls, he says. Coast Guard crews assisted 29 vessels during the period, responding to pleas stretching from the Aleutian Islands to the southeastern Alaska panhandle.