For a decade, the outbreaks of the latest scourge to plague East End bays, a roaming species of red algae called Cochlodinium, have steadily built in deadly reach and intensity. But after a summer of cool, dry weather, the levels and breadth of the blooms of “rust tide,” as scientists have dubbed it for the brownish-red color created where the dinoflagellate is flourishing, were the lowest this year since 2007.
And those who watch the bays most closely say that nature’s response to the absence of the microscopic killer has been nearly as marked—in a positive way—as it was to its emergence, which decimated marine populations.
Fishermen who work the Peconics and eastern Shinnecock Bay, where Cochlodinium blooms have been the worst, say that in its absence this summer, more fish remained in the bay through late summer and into fall, more young-of-the-year survived to migrate, and more adult bay scallops now litter the bottoms as the November harvest approaches than have been seen in years.
“You wouldn’t believe how everything lit up,” fisherman Kenny Mades said. “All summer long, everything hung around. The bunker stayed in the bay. There were lots of little snappers, little porgies—we had a set of little weakfish like I hadn’t seen since the 1970s. I saw shrimp, the big ones, for the first time in years. If you’re out there every day to see the difference, it’s amazing.”
Fishermen like Mr. Mades who have traditionally focused their efforts on the bays rather than the ocean have found the late summer and autumn fishing on a steady decline since the emergence of the rust tide, which typically blooms from mid-July through October. But this year, they say, the fishing was great through August and September.
“It’s been the best summer and fall fishery we’ve had in many years,” bayman Jon Semlear said. “In years past, I was basically done by September, a few fish here and there … almost not worth going. This year, I’m catching lots of fluke, baby porgies. Snappers are still in the bay.”
Those who also have blamed the rust tide for the struggles of bay scallop harvests, despite some apparently bountiful “sets” of young-of-the-year, may find further dots to connect with this year’s harvest. Scientists from SUNY/C.W. Post say that adult bay scallop stocks look to be robust this year.
“There seem to be a pretty good number of adult scallops just about everywhere we’ve looked,” said Steve Tettlebach, Ph.D., who leads a team of scientists that does population surveys of bay scallops each spring and fall. “We’re seeing more scallops this year than we did last year. We’re also seeing a lot more juvenile sea bass, more of a bivalve called a jingle shell, and more [snails]. We looked for evidence of a die-off of adult scallops this year, and we haven’t seen it like we did the last couple of years.”
In spring of 2012, Dr. Tettlebach’s scientists found one of the largest sets of bay scallops seen in decades, sparking talk of a return to the banner harvests of the 1970s and 1980s. But by fall, as many as 90 percent of the adult scallops had died, and rust tide was the first thing most baymen blamed. Dr. Tettlebach and other scientists studying the algae blooms have said the rust tide could be a substantial factor in the deaths of scallops and declines in finfish, but probably not the only culprit. This fall’s scallop harvest may be a bellwether.
“We have previously exposed scallops to rust tide in the lab … and we have seen that they expire when exposed to high densities for several days,” said Christopher Gobler, Ph.D., a professor at Stony Brook University and an expert on harmful algal blooms. “The rust tide was extremely intense in 2012 and 2013, and many scallops died off before the harvest occurred. We can let 2014 be the next phase of this observational experiment. If the scallop survival is good in 2014, with this extremely mild rust tide, it would provide further evidence to support the hypothesis that die-offs are caused, in part, by rust tide.”
The rust tide first appeared in eastern Shinnecock Bay in 2004 and has expanded its reach and intensity steadily since. In 2013, the rust tide blooms, which form in tiger-striped clusters at the surface of the water during the day and settle to the bottom at night, spread from the westernmost nooks and crannies of the Peconics all the way to Orient and eastern Gardiners Bay.
This year, the blooms appeared only in a few small harbors and in one corner of Shinnecock Bay. They also were short-lived, rising in enclosed creeks like Sag Harbor Cove and Three Mile Harbor during August, and then in Shinnecock for two weeks in September.
The timing and location of the blooms lent some credence to the patterns that scientists studying the blooms had tagged to Cochlodinium blooms. Dr. Gobler and other scientists have linked algae blooms like rust tide and the infamous brown tide scourge of the 1980s and 1990s to increasing amounts of nitrogen in local waters, flushed there by rain runoff and flowing groundwater tainted by chemical fertilizers and leaking household septic wastewater. While a general increase in nitrogen levels in the bay has led to the emergence of harmful algae blooms in the last three decades, variables like temperature and rainfall can drive the intensity and breadth from year to year.
“The link to temperature has always been apparent and was even clearer this year as the rust tide formed only during early September, which was significantly warmer than most of August,” Dr. Gobler said. “The other big issue this year was drought. We know these events are promoted by excessive nitrogen loading. We have seen the events in the past intensify following a major rainfall that pulses nitrogen into the bays. We simply did not have any of those events during August and early September, and thus the blooms were limited by the nitrogen supply.”
Whatever the reason for the restrained blooms, baymen say that it is clear local waters are not going to return to their former glory until the various toxic algae are expurgated.
“Eelgrass grew better this summer, better than in years—same thing happened in 1992, when we had that October nor’easter that flushed this place out really good, and in 1993 and 1994 we had good sets of fish and scallops,” Mr. Mades, the bayman, said. “If you could get things back to where they’re halfway decent, it would make an amazing difference. We need to get the water back to where it was about 45 years ago. If that’s possible, things would change dramatically.”