Pogies are the most popular lobster bait after herring.

Thousands of dead pogies, a type of fish used for bait, have appeared along the shores of Middle and Maquoit bays in Brunswick, police said Sunday.

The Brunswick Police Marine Resource & Harbor Management Division said it was following up on numerous complaints of “hundreds of thousands of dead fish” in the two bays. Commissioner Patrick Keliher of the Maine Department of Marine Resources explained to the division in an email that the floating dead fish were the result of an incident in which a fishing vessel in the intertidal areas had been unable to handle such a large catch.

“The fish kill incident is not the result of low oxygen content in the water or predation,” Brunswick police said in a statement. “Oxygen contents are being monitored by Friends of Casco Bay. The dead fish show no signs of predation by larger fish.”

The town of Brunswick has a cleanup process in place that involves asking local lobstermen and shellfish harvesters to come collect the excess fish for crab and lobster bait, police said. Local fishermen will be conducting coastal cleanup Monday at 10 a.m. in Maquoit Bay and 10:30 a.m. in Middle Bay, which will be followed up with “efforts from local youths to remove the rotting dead fish from the shoreline.”