to the seed
New town shellfish biologist works on propagation, predator control
BY PETER B. BRACE INDEPENDENT WRITER
Jeff Mercer is making Second Bend into a nursery for the just under one million scallop seed he is growing out next to the town's marine lab on Brant Point.

Mercer, who Marine Superintendent Dave Fronzuto hired this spring to fill the vacant town biologist position, is babysitting the scallop seed from Nantucket bay scallops that Town Biologist Keith Conant and the Shellfish & Harbor Advisory Board (SHAB) spawned off island this spring to augment ailing island populations.

With some now as large as 15 millimeters, Mercer reports the seed in good health and responding well to being grown out in the town's floating upwellers.

"Right now, about 90 percent have survived, I mean, we haven't seen much mortality at all and I would say that the average size is seven or eight millimeters and some as big as 15 millimeters," said Mercer.

Ever since former Town Biologist Tracy Sundell retired to teach yoga two years ago, the Marine & Coastal Resources Department has been without a shellfish biologist to handle shelltending fish propagation.

PHOTOS BY ROB BENCHLEY/The Independent In addition to tending to upwellers in the harbor at Brant Point, Jeff Mercer sets traps for green crabs, one of the bay scallops' most aggressive predators. In the close-up, he holds a fair number of scallops that have grown out to 20 to 25 millimeters.

When former shellfish biologist Keith Conant advanced to Sundell's job, shellfish spawning and grow-out duties fell on him and several summer interns. But now there is Mercer, 25, who is filling the void none too soon, according to Fronzuto who labeled Mercer "a Godsend" at the Aug. 21 SHAB meeting. Conant agrees.

"He's doing a good job, he jumped right in," said Conant who added that Mercer will not be serving as a shellfish warden because Conant wants him to benefit from a healthy relationship with the scallopers. "He's getting to know the island; he's getting to know our routines here, our sampling schedules; he's getting to know the lab and has some ideas that can help us out in the future. He's going to work out pretty well, I think."

Mercer, has been on the job since the end of July and is already neck-deep in all the duties that Conant could not give his complete attention to, including scallop, oyster, soft-shell clam and quahog grow-out and predator control.

"This year, we're doing transect surveys of Second Bend to see what the natural population is like out there, so we'll scuba dive and collect all the scallops in the transect and measure their growth rings," said Mercer. "We're basically removing all the natural scallops from Second Bend and that's going to serve as our nursery, so when we go back to Second Bend next year, we'll be able to tell the survival of the transplanted scallops."

To make their introduction into the wild as smooth as possible, Mercer also set five traps around Second Bend that he monitors weekly in an effort to catch as many of the green crabs living there as possible. One of the bay scallop's most aggressive predators and invasive species, green crabs, once removed from Second Bend, said Mercer, helps restore this part of the harbor system back to its normal state.

He expects to release the scallops into Second Bend in late fall when much of the marine life, including green crabs and other predators have gone dormant for the winter.

In addition to scallop grow-out, Mercer's other duties so far have included placing 200 lab-grown oysters on the rip-wrap near Old North Wharf, distributing 200 soft-shell clams in the eastern lobe of Polpis Harbor and growing 1,000 quahog seed to releasable size in the town's upwellers.

He is also monitoring the town's 25 spat lines.

Anchored in the harbor and held afloat with buoys, the spat lines have plastic mesh bags packed with monofilament dangling from them onto which scallop larvae attach themselves after spawning occurs. The number of baby scallops found in the spat bags is the town's yardstick for measuring what procreation is like from year to year. This year, according to Mercer, is not looking so good.

"We've brought in six out of eight spat lines and the amount of spat we're getting is very low," he said. "The most we got is 190 [scallops] out of 25 bags, so the reproductive potential for scallops is pretty low."

Mercer said the job is more or less what he expected and that he is psyched to be living on Nantucket and integrating himself into the island community. Before coming to Nantucket, Mercer worked as a graduate research assistant on Swan's Island, Maine, through the Shoals Marine Laboratory of Appledore Island, Isles of Shoals, Maine. He has a bachelor of science degree in biology with an ecology focus from Emory University of Atlanta, Ga., and a master's of science in biological oceanography

from the University of Connecticut. I