By Jason McLure

LITTLETON, New Hampshire (Reuters) - New England fishing quotas for cod, haddock and yellowtail flounder may be cut by 70 percent next year due to their depleted populations, a U.S. government official said.

Fishermen scrambled to come up with an economic plan to protect themselves from any drastic quota reduction, which could make the fish harder to find on restaurant menus and in supermarkets.

Allison McHale, a spokeswoman for the regional fisheries office of the National Oceanic and Atmospheric Administration, said recent studies of fish populations could justify cuts of as much as 70 percent for cod and haddock and 50 percent for yellowtail flounder.

Overfishing is not thought to be the sole culprit.

"It's beyond just fishing," McHale told Reuters. "There are various factors we're investigating."

Fishermen suspect such factors as climate change and the rapid growth of predators including seals and dogfish, a small shark that feeds on juvenile cod and other bottom feeders.

A recommendation on next year's quotas from an advisory council that includes state environmental officials and fishermen may be released next month, and NOAA will announce the final quotas in the spring, McHale said.

"It's really scary for the fishermen," said Ben Martens, director of the Maine Coast Fishermen's Association, which represents small commercial fishermen. "While these cuts are very detrimental, some of them are needed. We're not seeing a lot of fish in the water and our fishermen don't want to be fishing down to the last codfish."

In response, fishermen in Maine and Massachusetts are asking the federal government to declare their North Atlantic fishery a federal disaster area, a move that could lead to millions of dollars in aid, including government purchases of excess fishing boats and permits.

Two recent assessments of cod found there were only enough spawning fish to meet 8 percent of a target level of 140,424 tons at Georges Bank, off Cape Cod, Massachusetts, and 20 percent of targeted levels in the Gulf of Maine.

New England's bottom-fishing industry once fed millions of people but has dwindled as species such as Atlantic halibut and ocean perch have become commercially extinct.

(Editing by Barbara Goldberg and Eric Beech)