Red Tide Spurs Concerns For Fall Scallop Harvest

With last month’s return of the destructive “red tide” algae blooms, concerns are once again turning to how they could affect the East End’s most iconic wild species—the bay scallop—as the fall harvest approaches.

After last year’s late summer die-off of scallops, which most observers have blamed on the destructive red algae called cochlodinium, many are keeping a close eye on current scallop populations as the potentially deadly blooms spread again this year.

According to a team of scientists keeping tabs on bay scallop density on local bay bottoms, things were looking good when summer started. Last year’s adult scallops produced giant “sets” of baby scallops, the second largest of the last decade. And surveys of bay bottoms this spring showed that most of those scallops had survived the harsh winter, leaving large numbers to spawn again in early summer and, hopefully, feed a bountiful harvest this fall and winter.

Dr. Stephen Tettlebach, a professor at Long Island University who has led the bay scallop surveys for the last nine years, said the number of adult scallops his researchers counted this spring was only slightly lower than the numbers seen in early 2012, a dip he said was likely due to the harsh winter. In contrast, the winter of 2011-12 was one of the warmest on record.

If this year’s crop of scallops survives to November, the harvest could be a robust one.

But last year’s pre-summer counts were the largest in a decade, leading to forecasts of the most bountiful harvest since the 1990s. By the time the scientists returned for the post-summer surveys in October, however, they found that as many as 90 percent of the adult scallops in some areas had died. Cochlodinium is not harmful to humans but has been shown to be fatal to fish and shellfish, and has been blamed for the death of fish caught in traps and even, in some instances, the open waters of shallow creeks.

Most scientists and baymen have blamed last year’s die-offs on the red tide blooms, which reached levels of density, range and longevity not seen before in the 10 years they have been occurring in local waters. The 2012 blooms started in late July, nearly a month earlier than this year, and lasted into October. It was also the first time the cochlodinium blooms had taken place in East Hampton waters, in Gardiners Bay and Three Mile Harbor. Both areas saw large die-offs of scallops.

The two areas that did not suffer large scallop die-offs—Cold Spring Pond in Southampton and Napeague Harbor in East Hampton—did not have red tide blooms in the summer.

Still, Dr. Tettlebach remains unconvinced that red tide is to blame for the massive die-offs in 2012, saying they could have been caused by the warm winter. He explained that the scallops did not go into a period of dormancy, as they usually do when the temperature falls, and were therefore more stressed by the end of the summer than they normally would have been.

Nonetheless, his team of researchers did some preliminary dives two weeks ago to check up on how this year's scallops are doing.

“We did a dive last week at a spot where we saw a lot of scallop mortality last year and there was some mortality, but nothing crazy like last year,” Dr. Tettlebach said last week. “We’ll see what happens in the next few weeks.”

Dr. Tettlebach also noted that the red tide emerged only in the third week of August this year, so if it is, in fact, to blame for the die-off the worst of its impact is probably yet to come. His team will conduct its full annual fall surveys over the first three weeks of October.

The baymen who most look forward to the profitable winter scallop harvest are giving mixed forecasts for the coming year’s harvest.

Southampton Town baymen reported seeing a good number of baby scallops, called “bugs,” even after last summer’s die-off, but have not yet noticed many signs of a particular bounty so far this summer.

“We haven’t been [out] to look, but it didn’t look great from last summer,” East Hampton bayman Danny Lester said recently. “You have to have small ones to have the big ones. Last year didn’t have many small ones, which means we’re not gonna have any scallops next year.”