The ocean’s resources are renewable if they’re managed well. That demands science-based management, but when there’s not enough science, the door is wide open for manipulation by special interests.

That sort of manipulation is occurring right now, and it illustrates the need for continued research and additional federal fisheries observers.

Recently, two groups of groundfishermen filed suit against the National Oceanic and Atmospheric Administration, the National Marine Fisheries Service and the Secretary of Commerce. The suit seeks to ban another group of fishermen – those who engage in mid-water trawling for herring and mackerel – from certain areas of the ocean.

The rationale? These areas are closed to commercial groundfishing by fisheries regulators in an attempt to ensure sufficient spawning stocks to rebuild roughly a dozen species depleted by overfishing.

Groundfish, as the name implies, are species that live on and near the bottom of the ocean – species such as cod, haddock and flounder. Some groundfish species are in trouble. But fisheries scientists say that stocks of herring and mackerel are robust. Herring are vitally important to Maine’s lobster fishery, because 80 percent of the annual northeast herring catch is used as bait.

Herring and mackerel are often found in the areas closed to groundfishing. Because they usually swim higher in the water than groundfish, scientists and fisheries regulators have determined that fishing for these pelagic species in these areas does not have a biologically significant effect on groundfish spawning stocks. Recreational groundfishing is permitted in these areas for the same reason.

The lawsuit was filed after NOAA rejected a petition demanding closure of these areas to midwater trawlers. In rejecting the petition, NOAA noted that observer data indicates levels of bycatch, the capture of nontargeted species, were within an acceptable range and that the plaintiffs had not provided new information to justify emergency action. Dockside catch inspections and other regulatory processes support this view.

Midwater trawlers have minimal contact with groundfish for several good reasons. Beside the fact that herring and mackerel are usually found higher in the water column, midwater trawl nets are not built to withstand sustained contact with the ocean floor. The nets are also designed to exclude nontargeted species; at their outer edges, the mesh is large enough to let a city bus pass through sideways. Only the last segment of the net – the brailer, which has an opening about 25-feet in diameter – has a mesh size small enough to keep most fish.

Bycatch is a fact of life in every commercial and recreational fishery, regardless of the type of gear used. Midwater trawlers do, in fact, take some groundfish such as haddock as bycatch. The relevant question is not whether it occurs, but rather if the amount of bycatch is biologically significant. The available science indicates that it’s not.

Regulations on the midwater trawl fleet already include specific protections for groundfish. For example, midwater trawlers are required to keep bycaught haddock and to report it. If as little as 0.02 percent of the total allowable catch for haddock is caught by midwater trawlers, the primary herring grounds – 90 percent of the area north of Cape Cod – are closed for the season.

Many of the most vocal opponents of midwater trawling are directly funded by multimillion dollar environmental activist groups and aided by slickly produced “reports” that present emotionally compelling doom-and-gloom scenarios. The reports claim to be science based, but in fact rely mostly on anecdotes and non peer-reviewed studies funded by the same activist groups, which also fund the environmental litigation firms that bring the lawsuits.

It’s an all-too-cozy arrangement that makes for bad policy and even worse science – and objective science is what’s needed to properly manage the ocean’s resources.

To that end, the midwater trawl fleet has submitted a grant request for an objective, detailed study of bycatch resulting from midwater trawling activities. And although federal fisheries observers ride along on midwater boats more frequently than they do with many fisheries, midwater boat owners are attempting to get the federal government to fund more fisheries observers.

As more data is collected, fisheries managers will be able to make better decisions about how and where boats should fish. That requires action and commitment on the part of the government. Today, it’s too easy for special interests with finely-tuned public relations machines to manipulate the process.

Billie Schofield is the general manager of Norpel, a fish processor in New Bedford, Mass. Dave Ellenton is the general manager of Cape Seafoods in Gloucester, Mass. Leslie Raber is the owner of Ocean Spray Partnership and the fishing vessel Providian, based in Portland.