Herring numbers on the Mattapoisett River fell for the second year in a row, according to a recent report from Alewives Anonymous, a tri-town organization that monitors the fish’s numbers.

This year, 18,540 herring were counted on the Mattapoisett river, a notable decrease from the 42,332 counted in 2015.

The previous year, 2014, saw the highest numbers in years with 55,429 fish counted, a 156 percent increase above the previous year’s number.

“Evidence of herring being present at Mattapoisett (gulls, cormorants, seals) was not observed nor were they seen during any of the brush and tree clearing activities in the river during the spring,” according to Art Benner, president of Alewives Anonymous. “Counting conditions were ideal this spring, the counter appears to have functioned without errors.”

A device was installed this year at Leonard’s Pond on the Sippican River as well. That counter recorded 1,126 fish.

“It has been a few years that herring have not been able to get into Leonard’s pond,” said Benner. “We are hoping that there was a lot of Sippican River herring that stayed in Hathaway’s Pond and spawned there and over the next few years will again become accustomed to continuing further up the river to Leonard’s Pond.”

The Buzzards Bay Coalition has a counter at the herring at Hathaway’s Pond that showed 172 fish, but Tony Williams, the Coalition’s director of monitoring programs, said he hasn’t seen any actual herring.

“I don’t know if I’m counting weeds, a turtle swimming through the tunnel [or] river herring,” he said.

Williams said it’s possible herring are using an older ladder at the pond dam as well.

The reason for the shifting numbers is unknown, but Williams said herring counts on the Acushnet River have seen a similar dip to that of Rochester’s waters.

Working with the Massachusetts Division of Marine Fisheries, organizations such as the Buzzards Bay Coalition and Alewives Anonymous are hoping to help find the cause of the low numbers for a fish that was once abundant in the area.

A moratorium against catching the herring remains in place on the Mattapoisett and Sippican rivers, according to Benner.