From the Cape Cod Times:
This year, when the first days of spring really feel springlike, it's not just flowers that are early.
Alewives, one of two Atlantic river herring species, have started their inland spawning migration weeks ahead of their usual time.
"Based on the warm temperatures, we decided to start our volunteers early," said Jo Ann Muramoto, senior scientist at the Association to Preserve Cape Cod and a member of the River Herring Network who coordinates volunteer fish counters at the Cape's herring runs.
The Cape doesn't usually see significant numbers of herring inland until early to mid-April. But reports began coming into Muramoto last week of fish heading upstream in runs in Mashpee, North Falmouth, Bourne, Brewster, Orleans, Eastham and Wellfleet.
These were not just so-called "scouts" — individuals or pairs of fish that venture upstream as early as February and then possibly return to the main body of fish offshore for some unknown reason. This year, groups of up to 20 fish have been spotted in March.
After spending the fall and winter in offshore waters, sexually mature alewives gather in large schools around the mouths of rivers, streams and other estuaries waiting for water temperatures to reach 51 degrees. Blueback herring, the Cape's other species, don't venture upstream until water temperatures reach 57.
As they wait, river herring's bodies adjust to the increased flow of fresh water, undergoing physiological and other changes that maintain the salt balance between their body fluids and the surrounding water. Their gills change to retain salt instead of expelling it, and they stop swallowing water, except with food.
One big problem this year may be low water levels in the smaller runs, Muramoto said.
But that's just one of a multitude of things that have made it tough for a fish that once clogged waterways from Newfoundland to the Carolinas every spring.
River herring numbers have long been in decline from historic levels but in 2005 they seemed to fall off a cliff all along the East Coast.
The Bournedale run, the Cape's most prolific, saw 102,000 herring in 2005, just one-fifth the number making the inland pilgrimage in 1996. Those numbers were echoed all along the Atlantic seaboard and resulted in a coastwide moratorium in 2006 on catching alewife or blueback herring that now is in place at least until 2015.
Habitat loss, degraded water quality, clogged or obstructed inland migration routes, and overfishing have driven population levels down. Now some experts believe fishermen going after offshore Atlantic herring — the alewive's saltwater cousins — may also be catching river herring in the mix.
Next month, the New England Fishery Management Council will vote on regulations that could diminish the bycatch of river herring by the Atlantic herring fleet. The next public hearing on those proposed regulations is set for Tuesday in Plymouth.
Massachusetts has more than 150 man-made fish passageways — more than any other coastal state — to allow herring to reach their spawning grounds. The state Division of Marine Fisheries has its own fishway construction crew and has been working for more than 50 years to support anadromous fish — those that spend part of their lives in saltwater and part in fresh.
The federal government has also been active in helping towns to improve tidal flow and access into estuaries.
At Brewster's Paines Creek, the National Oceanic and Atmospheric Administration spent $1.67 million to widen a culvert from 3 to 18 feet. That helped restore water quality in 20 acres of marsh and helped herring to get to more than 400 acres of prime spawning habitat in the Stony Brook herring run. The $30 million Cape Cod Water Resources Restoration Project, with 76 projects in 15 Cape towns, includes many improvements that will benefit herring.
And, local groups of volunteers, often led by town-appointed herring wardens, have worked to clear old dilapidated runs, build new ones, overcome obstacles and improve water quality.
But all these efforts, including the seven-year moratorium, have done relatively little to rebuild the species.
"We're seeing a little uptick in a couple of places," said Brad Chase of the Division of Marine Fisheries.
The state and towns have been devoting more effort to counting and getting biological information from these fish, which may pay off with better population estimates, he said. But no one has seen any dramatic increase.
"Yet, we're very hopeful," Chase said.