The ban on taking of alewives and blueback herring from most of the state's inland and marine waters has been extended for its ninth year, the state Department of Environmental Protection announced Friday.

"Since 2002, states along the East Coast have all experienced dramatic declines in river herring populations," Deputy Commissioner Susan Frechette said in a news release announcing the ban, which is now extended through March 31, 2012. "To combat this decline, the closure of these fisheries must remain in place."

Alewife and blueback herring, collectively referred to as river herring, hatch in freshwater, migrate to the ocean to grow, then return to freshwater to spawn. Historically, millions of river herring returned to Connecticut rivers and streams each year. In 1985, more than 630,000 blueback herring passed over the fishlift on the Holyoke Dam, on the Connecticut River in Massachusetts. In 2006, only 21 passed the dam, and last year the number was 76. While the reasons for these historically low levels are not fully understood, DEP biologists believe predation by increasingly abundant striped bass and undocumented catch in the ocean may be important factors.

"River herring comprise a large portion of the diet of many species of freshwater and marine gamefish, as well as osprey, bald eagle, harbor seals, porpoise, egrets, kingfishers and river otter," said William Hyatt, chief of DEP's Bureau of Natural Resources, "and it is important to protect river herring runs as a means of conserving all of these other species." DEP wildlife biologists have noted that strong runs of river herring enhance the survival rate of osprey chicks.

Non-migratory alewife populations are also established in 12 lakes and ponds in Connecticut, including Rogers Lake in Old Lyme, Uncas Pond in Lyme, Amos Lake in Preston and Beach Pond in Voluntown. Alewives in these lakes may still be taken by angling and scoop net.

The ban is expected to remain until there are indications that the population has recovered and could sustain harvest, Hyatt said. The DEP will continue monitoring the populations, and is working to enhance river herring stocks by transplanting adult herring from streams with healthy runs into those with depleted runs, removing obsolete dams and building fishways. The U.S. Fish & Wildlife Service is assisting the DEP with the transplantation effort.

The Atlantic States Marine Fisheries Commission has requires all coastal states to improve their monitoring of river herring runs and take positive conservation actions. The New England Fishery Management Council is also considering changes to the Atlantic herring fishery in federal waters to reduce the accidental harvest of river herring in the ocean.