For centuries, commercial fishing has been about manipulating natural systems to the greatest human benefit – often without considering, or even knowing, the ripple effects of such actions.

Today, a new idea called ecosystem management is taking hold of the nation.

“Everybody’s talking about it … like the weather,” University of Maine professor Jim Wilson said recently.

To teach his students about ecosystem-based fisheries – the deceptively simple idea of restricting our fisheries in the interest of preserving all of the ocean creatures’ relationships to one another – Wilson turns to storytelling.

You see, he explained during a recent interview, urchins have to live in balance with the kelp forests where they live. Urchins eat kelp, keeping the seaweed under control, and preserving the open stretches of sand where their larvae start life.

But about 15 years ago, Maine overfished its urchins, tempted by a lucrative Japanese sushi market. Today, the larvae drop into an overgrown kelp forest where tiny crabs and other predators snatch them up before they can grow and breed. The balance of nature has been shifted, and, without help, the urchins may never recover.

In this and countless other examples worldwide, fisheries managers’ ignorance of the ecosystem’s delicate balance may have destroyed it, Wilson said.

Ecosystem management broke onto the national scene in a big way nearly a decade ago, when a National Marine Fisheries Service panel endorsed the concept in hopes it could save struggling fisheries.

Last spring, the privately funded Pew Oceans Commission recommended that the federal government reorganize its policies based on ecosystems, calling the shift both “a practical measure and a moral obligation as the stewards of our planet.”

Now, U.S. Sen. Olympia Snowe’s pending reauthorization of the mother of all federal fisheries laws – the Magnusson-Stevens Act – includes a requirement that fisheries managers study ecosystem approaches throughout the country, and that at least one region get an ecosystem management pilot program on the ground in the next decade.

“Almost everybody gets [ecosystem management] as a matter of common sense,” said Philip Conkling, president of the Rockland-based Island Institute and a member of the National Marine Fisheries Service panel.

The trouble lies in applying such a simple idea to the complex world of modern fisheries management.

The existing fisheries management system is “clunky and antiquated,” said Roger Fleming of the Conservation Law Foundation in Rockland.

A better plan would focus more on how we fish than on impossible-to-enforce absolute quotas, Wilson said. For example, open fishing times might be designed around a fish’s life cycle or particular equipment might not be permitted in places where it would disturb shellfish nursery grounds.

Such a system, designed around the details of local fish behavior, has the potential to be much more responsive to scientists and fishermen alike, he said.

Perhaps a well-designed ecosystem management program could even heal the long-standing rift between fishermen struggling to make a living and the scientists whom they blame for ever-increasing restrictions, Wilson said.

Even with skilled federal scientists and sophisticated computer models, modeling every aspect of ocean life is beyond the realm of possibility, he said.

“You want to use the best science that’s available, but it’s always going to change and evolve,” Fleming agreed, adding that ecosystem management can’t afford to wait for “perfect” science.

“We have to recognize that we don’t have much control,” Wilson said.

But the key to ecosystem management is understanding enough about fish life that human actions don’t disturb it – so whom better to ask than the fishing families that have generations of knowledge, he said.

“Ecosystem management is really about people,” Conkling agreed.

Maine is a particularly appropriate location for an ecosystem management pilot study, fisheries policy experts said.

Mainers already are familiar with the successful lobster zone management system, which incorporates many characteristics of ecosystem management. Mainers live in tight-knit communities that have a long relationship with the sea.

And with the combination of federal restrictions that many say favor southern New England fishermen, and the struggling populations of groundfish, the Down East commercial fishery has nothing to lose, Wilson said.

In fact, an ecosystem-based groundfish industry that uses fishing methods as well as quotas, might bring some diversity – and thus, some economic safety – back to a region that’s almost wholly dependent on lobstering. No one knows, for instance, exactly why the lobsters have boomed, but they could crash just as unexpectedly, destroying entire communities, he said.

“It’s like managing an investment portfolio,” Fleming said. “You’ve got to be balancing your risk.”