Menhaden Population Booming in Rhode Island Waters

Posted by Wayne G. Barber

Here's a statistic, which is a best-guess estimate, but nonetheless difficult to wrap one's head around: On Tuesday, Oct. 6, there were 5.8 million pounds of menhaden swimming in the bay.

That isn't too hard to imagine if you looked down from the Pawtuxet River Bridge the following day, or actually, as it turns out, just about any time in the last two weeks. What you would have seen are thousands upon thousands of fish. Most of them were juvenile menhaden averaging about three inches long. Mixed in the schools – so thick that they looked like carpets – were a few adults of about 11 inches. And then there were the predators – the cormorants, sea gulls, terns and bluefish and stripers – gorging themselves.

"The menhaden population has absolutely exploded this year," says Christopher Deacutis.

Deacutis, supervisor of environmental science for the Department of Environmental Management, said large schools of the fish have been seen up and down the eastern seaboard, and there have been reports of humpback whales feeding off them last month in Long Island Sound. The whales haven't been reported in Rhode Island waters, but Deacutis suspects the menhaden are the reason why schools of common dolphins have been spotted at the mouth of Narragansett Bay.

Pawtuxet Cove isn't the only place the fish are plentiful. Large schools are being reported in coves throughout the bay, as well as in deeper waters. DEM contracts for "spotter planes" that are used to estimate the biomass of schools of menhaden. Those estimates have been arrived at through years of working with purse seiners, explains Nicole Lengyel, principal biologist with RIDEM Fish and Wildlife. The weight of a catch is compared to the size of a school, which is then used to estimate the biomass of other schools.

Lengyel said the state usually gets a "spring pulse" of adult menhaden that tapers off in June as they migrate north. There's usually a second late summer or fall pulse of juvenile fish migrating south in late August and into September. This summer, more menhaden stayed in the bay and the fall pulse picked up at the end of August, running through most of September.
Source: The Outdoor Wire