Slimed!  Nitrogen-fed mess chokes herring run, dissolves marshes

Jack Reynolds alongside the algae choked herring run to Cockeast Pond in Westport. The pond, too, is filling with the stuff.

Jack Reynolds alongside the algae choked herring run to Cockeast Pond in Westport. The pond, too, is filling with the stuff.

Jack Reynolds alongside the algae choked herring run to Cockeast Pond in Westport. The pond, too, is filling with the stuff.

The edge of a marsh collapses. Too much nitrogen may be to blame.

The edge of a marsh collapses. Too much nitrogen may be to blame.

Spectators to the spring herring arrival at Cockeast Pond near the harbor entrance were encouraged by what they saw.

Lots of the fish made the upstream swim through the realigned herring ditch up to and beneath River Road and then on into the 99-acre pond. Hopefully there they would spawn and send the next generation back out the ditch to sea later in the season.

“Local reports point to large numbers (of herring) running up into Cockeast Pond that could be the most seen in a decade,” said Brad Chse of the state Division of Marine Fisheries.

The forecast has become more gloomy since.

Jack Reynolds, president of the Westport Fishermen’s Association, showed why last week.

Walking along the edge of the ditch between River Road to where it empties into the harbor entrance he didn’t need to point to the problem.

It was everywhere — thick green slime filled the narrow channel. It floated in clumps and coated the bottom.

“It’s hard to imagine much making it through that mess,” he said.

Across the road it was much the same looking out over Cockeast Pond. More slime filled the west end of the ditch.

“And see those flat calm patches out on the pond? That’s more of it floating on the surface. Go out there and you can see it all over.”

Mr. Reynolds, Mr. Chase and others say they have seen plenty of the green growth here.

Mr. Chase said he saw green algae growing upstream of the culver in late May. “It struck me as higher than expected for that time of year.”

There was hardly any to be found a few years ago when they first dug out the herring ditch so that herring could make it back to the big coastal pond to spawn. Nor was there much when they improved the ditch last year to correct  some elevation issues (“herring don’t jump over drop-offs like salmon”) caused by the River Road culvert and approach.

“What’s disappointing is that this spring started out well – it was a promising run, probably the best right here in many years,” Mr. Reynolds said.

Mr. Reynolds worries now, though, that all those young herring are at peril.

“What happens is that when all that stuff dies and decomposes it uses up all the oxygen in the water,” he said. “The (herring) fry live in that pond all summer and if oxygen levels decline too much they could be in big trouble.”

Adding to his concern is that the herring run at other Westport places was less robust. “This was a bright spot,” Mr. Reynolds said.

As to the cause, Mr. Reynolds and Mr. Chase said there are many possible culprits — most falling under the general category of nitrogen.

His May observation “and reports I have heard of dense summer growth imply a eutrophication problem possibly enhanced by nutrient loading,” Mr. Chase said.

“You look out and see those lush green lawns — that’s probably part of it,” Mr. Reynolds said. There are more big shorefront houses than in years past. A fair number of these probably employ lawn service companies whose job it is to keep those lawns flawless “and that requires fertilizer. And then you get a good downpour and where do you think some of that fertilizer goes.”

Wildlife, including big flocks of Canadian geese that visit, contribute nitrogen-rich waste. And there may be a few failed septic systems out there as well.

“People think of nutrients as good things. Well too much of a good thing can kill a beautiful pond like this in a flash.”

As herring go, so do many other fish, including those sought by fishermen, Mr. Reynolds said.

It is the “unfortunate” role of the herring “to be food for many other species” — fish, birds and more. “They spend their lives being chased by things.”



Vanishing marshes

Slime isn’t the only thing that Mr. Reynolds say he and others who watch the river are worried about.

“We are losing the marshes in the river and losing them rapidly,” he said.

A lifelong fisherman — first in the river, then in a bigger offshore boat, now back in the river — “this place looks so much different than it did just a few years ago.”

He said that  “entire large marshes are dissolving right before our eyes.

“See, right here, he said, pointing to a grass-covered marsh near the ditch’s mouth. “It has collapsed right away from itself. And see the grass that is now in the water … how much thicker and greener it is.” That’s because it’s getting a constant bath of nitrogen rich water from up in the pond.

In healthy marshes, grass puts down intertwining roots that knit the thick brown base into a strong, solid mass. But when there its too much nitrogen, they don’t need deep roots to get all the nourishment they need. “And without those roots to hold it together that foundation just dissolves and falls away … Some really big marshes up the river are less than half what they were not so many years ago. A couple are almost gone.”