Flying over California's rugged central coast, Mike Sutton pointed to kelp forests and rocky reefs just below the water's surface that will soon be off-limits to fishing under one of the country's most ambitious plans to protect marine life.

"We're trying to make sure our oceans are [as] protected as our land," said Sutton, a marine expert at the Monterey Bay Aquarium.

Despite intense opposition from many fishermen, California wildlife regulators are creating the nation's most extensive network of "marine protected areas" — stretches of ocean where fishing will be banned or severely restricted.

The first chain of refuges, covering about 520 square kilometres and stretching from Santa Barbara to Half Moon Bay just south of San Francisco, is due to take effect early in 2007. The state plans similar protected zones along the more intensely fished coasts of northern and southern California.

Conservationists say such networks are a new approach to saving the oceans from overfishing. They believe California's plan could serve as a model for other states and countries.

"It's the beginning of a historic shift in how we restore, protect and manage our oceans," said Warner Chabot, the vice-president of the Ocean Conservancy.

"We're doing something that's as historic for the oceans as what Teddy Roosevelt did 100 years ago when he created national parks and forests."

The U.S. Fish and Game Commission voted for the Central Coast preserves in August after two years of negotiations between fishermen, conservationists and coastal residents. Conservation groups had sought even greater restrictions, but were generally pleased with the outcome.

The protected areas will include marine reserves where all fishing will be banned, as well as marine parks and conservation areas that will allow some forms of sport fishing.

All the restricted zones are designed to harbor rockfish, abalone, shellfish and other species that stay in one area, rather than migratory fish such as salmon and tuna. Sea otters and other marine mammals are expected to benefit from the increased food supply.

Criticism from fishing industry

Many fishermen, however, are embittered and feel the commission didn't listen to their input.

The planned restricted areas overlap with some of California's most productive fishing grounds, and commercial and recreational fishermen question whether they're even necessary given the existing array of state and federal regulations.

"We're duplicating conservation efforts unnecessarily," said Vern Goehring, manager of the California Fisheries Coalition. "There are significant actions already under way to prevent overfishing in California."

'We're being regulated out of business.'-Mike Rivets, 70, fisherman for salmon, crab and tuna

Fishermen say the no-fishing zones will put more pressure on areas outside the reserves and could lead to increased seafood imports from countries with fewer marine protections.

At Monterey's Fisherman's Wharf, longtime trollers and crabbers say the new restrictions will cripple their industry, hurt fishing communities and leave Californians with less fresh, local seafood.

"We're being regulated out of business," said Mike Rivets, a 70-year-old fisherman for salmon, crab and tuna.

In the Central Coast port of Morro Bay, Darby Neil is worried about the fate of Virg's Landing, the charter boat operation his grandfather started more than 40 years ago.

"They've already squeezed us down to nothing," Neil said. "It's already so severe that we really can't take anymore."

Collapse of seafood species forecast for 2048

But scientists say more must be done to protect marine life.

A report in a November issue of the journal Science warns that nearly a third of the world's seafood species have collapsed — meaning their catch has declined by 90 per cent or more — and all populations of fished species could collapse by 2048 if current fishing and pollution trends continue.

"We've mismanaged the oceans from abundance into scarcity," said Karen Garrison, an ocean expert at the Natural Resources Defense Council. "We can't protect our oceans without setting aside safe havens where fish can grow big and the whole food web can thrive."

Governments worldwide have been creating marine sanctuaries with various levels of restrictions for the past 40 years.

In June, U.S. President George W. Bush created the world's biggest protected marine area in the northwestern Hawaiian Islands, covering about 360,000 square kilometres of largely uninhabited islands, atolls and coral reefs where commercial fishing will be phased out over the next five years.

Australia created a network of reserves on the Great Barrier Reef in 2005. South Africa and New Zealand are working on plans to protect coastal fisheries.