Tuesday, April 26, 2011

The herring are here! Next year their passage will be easier.

This degraded fish ladder at Cedar Lake in Falmouth will be rebuilt in time for next year's herring migration.

By Abigail Franklin, Anadromous Fish Restoration Project Manager

The rivers have reached 50 degrees! On Cape Cod, river herring start to swim upstream to their spawning grounds when the temperature of the rivers and streams reaches 50 degrees Fahrenheit.  Migrating river herring have now been seen at all but one of the seven Cape Cod Water Resources Restoration Project fish passage sites. 

It’s exciting to see them after the long winter, and it’s even more exciting to know that when they arrive next year, they will discover new fish ladders and structures that will make it easier for them to swim to the ponds!

For example, this spring at the Marstons Mills River in Barnstable, the river herring are swimming through a flume that is deteriorating.  In the late 1800s the flume was constructed by citizens who wanted to help the fish bypass the cranberry bogs on their way to the spawning grounds at Middle Pond. Because of the sandy soil, the walls of the flume have a tendency to lean and fall into the stream.

Many efforts have been made over the years to repair and reconstruct the structure, and it is time to do so again.  Next year, the river herring will swim through a more structurally stable flume, and will not have to worry about the walls caving in on them!

At Cedar Lake in Falmouth, the river herring are swimming up a fish ladder that is disintegrating, and then through a sloped culvert with baffles under Bay Road. Next spring they will find a brand new ladder, and a level culvert under the road that will allow them to swim upstream faster.

And at Lower Red Brook in Bourne, river herring can only access a culvert under the railroad berm during high tides, and at low tides must wait around and avoid being eaten by big fish and birds.   Next spring, they will be able to reach the culvert during more of the tidal cycle thanks to the construction of rock weirs.

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