ROCHESTER — This year's count of herring in the Mattapoisett River was 16,049, a decrease from the 2019 total of 18,156, according to a report from Alewives Anonymous, a Rochester organization that records herring numbers for local rivers using electronic counters.

Alewives Anonymous President Art Benner said the decrease could have occurred for a number of reasons that Mother Nature controls. 

Debris in the river can obstruct the path for herring to swim up to Snipatuit Pond in Rochester and down to the Mattapoisett Harbor. 

This year’s drought could also have an effect on the life cycle of herring.

If there isn’t enough water in the river, the young herring can’t swim back to the bay and may be eaten by other fish in the pond such as bass. As for the adults, Benner “hopes those guys can make it back” so that they can spawn in future seasons. 

A second counter on the Sippican River at Leonard’s pond malfunctioned because it counted other types of fish beyond herring and counted fish more than once as they entered and exited the jumps multiple times.

The effect of the drought on the population may not be immediately seen, Bennet said. 

The decrease from the dry season will show up in 3 to 4 years, and the change will depend on how many sprats survive in Snipatuit Pond. 

At one point around the turn of the century, the report shows that there were upwards of 130,000 herring in the Mattapoisett River.

The long-term decrease could be accredited to trawlers who fished near the coastline and mistakenly caught river herring instead of ocean herring.

But the numbers have been slowly rising since its low point of 5,000 fish in 2004, two years before the state put a ban on catching herring. 

The 2019 count was the first increase recorded since the recovery of the herring population in 2014 to 55,429.