An environmental group has filed suit against state and federal fishery management agencies, saying the agencies turned responsibility for protecting shad and river herring populations into a finger-pointing blame game while the fish stocks declined.

Spawning populations of both species - which once packed the region's rivers each spring - are at, or near, all-time lows along the coast and in the Chesapeake Bay.

The suit, filed by Earthjustice in September against the National Marine Fisheries Service, the Atlantic States Marine Fisheries Commission and coastal states, contends fishery managers have done little to prevent the fish from being caught as bycatch in other fisheries.

"There has just been finger-pointing," said Roger Fleming, an attorney with Earthjustice. "These population levels have dropped so significantly that we have to do everything that we can to avoid their bycatch."

The suit was filed on behalf of New England anglers who are prohibited from catching the fish because of their low populations.

River herring include two species, alewives and blueback herring. They, like shad, are anadromous species that return to their native rivers to spawn, but spend most of their lives migrating along the East Coast.

Most of the fisheries targeting those species historically took place in rivers during spring spawning runs. As a result, their catches have been regulated primarily by the ASMFC, which has ratcheted back allowable catches over the years.

Much of the problem, according to the suit, is that the ASMFC's jurisdiction only includes state waters. The fish spend most of their lives in federal waters, those more than 3 miles offshore.

Anecdotal evidence suggests that large numbers of shad and river herring are caught by fisheries targeting other species in federal waters - potentially more than the total caught in the few remaining fisheries in state waters.

Last year, the ASMFC asked the federal government to take emergency action to gather data about bycatch of shad and river herring in federal waters, but their request was rejected.

"That was one trigger for the suit - seeing the ASMFC ask for emergency action, and being denied pretty bluntly," Fleming said.

Federal managers have said that data indicating excessive bycatch of shad and river herring is poor and too anecdotal to constitute an emergency. But the suit says the federal government has placed too little emphasis on getting better data by not placing observers on vessels in fisheries thought to be catching shad and river herring.

The NMFS has never developed a management plan for shad and river herring because the fish are not specifically targeted in federal waters. But the suit contends that the Magnuson-Stevens Act, which governs catches in federal areas, requires that management plans be developed for any species that is overfished and requires conservation measures.

In addition, the suit said the act requires management plans regulating fisheries in which river herring and shad are being caught - such as the mackerel and Atlantic herring fisheries - to set bycatch limits and to collect better information about the types of fish being caught.

The suit contends the ASMFC has also failed to collect adequate information about the species that would have allowed it to set coastwide bycatch limits for shad and river herring. That information would have allowed it to more effectively coordinate with federal fishery managers, the suit said. It also said existing management plans for the species have failed to adequately protect the stock.

Neither the NFMS nor the ASMFC comment on active suits.

But several conservation groups, who are worried that the depletion of shad and river herring are depriving predator fish of an important food source, applauded the action.

"We are finally airing out this argument between state and federal responsibilities," said Pam Gromen, executive director of the National Coalition for Marine Conservation. "Finally, I'm hoping we will have a definitive decision for the responsibility for managing these fish in federal waters, and that people are held responsible for it."

Shad, and to a lesser extent river herring, have been restoration priorities in the Bay watershed. But despite stocking hundreds of millions of fish and spending tens of millions of dollars over the last two decades, most spawning runs in Bay tributaries have shown little improvement.

Many biologists suspect factors outside the Bay - likely ocean fisheries - play a role, but acknowledge that available monitoring data are inconclusive.

The regional management councils that develop fishery plans for federal waters have begun considering amending management plans to protect shad and river herring, but advocates say any final decision is likely years away. They hope the suit leads to accelerated action.

"You have species that probably could qualify for endangered species listings in some areas," said Ken Stump, policy director of the Marine Fish Conservation Network. "They don't really have the luxury of waiting until we get our act together."

Both species once made spring spawning runs far up coastal rivers in numbers unfathomable to people today. Streams were sometimes so packed with migrating fish that wagons would crush them as they crossed.