New testing system provides early warning of toxic algae blooms

            When a large bloom of harmful algae appeared in lower Narragansett Bay in October 2016 – and again in early 2017 -- the state’s testing methods were not refined enough to detect it before the toxins produced by the algae had contaminated local shellfish. That scenario is not likely to happen in the future, now that the Rhode Island Department of Health’s laboratories have acquired new instrumentation and analytical tests to detect the toxins early and to determine when they have dissipated enough so shellfish harvesting may resume.

            “It’s an improved early warning system so we don’t have to worry about future problems with harmful algae blooms,” said Henry Leibovitz, the chief environmental laboratory scientist at the Department of Health. “We’re trying to safeguard public health, safeguard our shellfish economy, and safeguard the state’s shellfish reputation.”

            The new testing system was approved in September by the Food and Drug Administration’s National Shellfish Sanitation Program, which regulates the interstate sale of shellfish.

            The 2016 and 2017 blooms, which Leibovitz said were the first harmful algae blooms to occur in Narragansett Bay, forced the closure of parts of the bay to shellfishing and required that some previously-harvested shellfish be removed from the market. It was caused by the

Pseudo-nitzschia (Rozalind Jester)

phytoplankton Pseudo-nitzschia, which, when concentrated in large numbers, can produce enough of the biotoxin domoic acid to contaminate shellfish and cause those who eat the shellfish to contract amnesic shellfish poisoning.

            Another kind of plankton, Alexandrium, produces a biotoxin that can cause paralytic shellfish poisoning. Both Pseudo-nitzschia and Alexandrium occur in Rhode Island waters year-round, but they are only harmful when concentrations are high and the toxins they produce reach 20 parts per million.

            According to Leibovitz, the state’s previous testing system was “a primitive screening test” somewhat like a pregnancy test – it could determine whether the toxins had reached the limit, but not how far over or below that threshold they were. And it was not sensitive enough to detect the lower concentrations of the toxins that would signal that the bloom had dissipated and shellfish harvesting could begin again. To reopen shellfish beds to harvest, the state had to send water and shellfish samples to a private laboratory in Maine, the only lab in the country capable of conducting the test at the time.

            Now that Rhode Island has an FDA-approved lab, it is offering its services to nearby states.

            The state's Harmful Algae Bloom and Shellfish Biotoxin Monitoring and Contingency Plan directs the Rhode Island Department of Environmental Management to collect weekly water samples from areas of the bay where shellfish are harvested. The samples are tested in the Department of Health lab. If large numbers of harmful algae species are found, the plankton are tested to determine the concentration of toxins they are producing. If toxin concentrations are high, shellfish are then tested and a decision is made whether to close particular areas to harvesting.

            The problem of harmful algae blooms has been an annual concern along the coast of Maine for many years, and scientists speculate that it could be a more frequent problem in southern New England in coming years, too.

            “We think the problem is knocking on our door,” said Leibovitz, “and we need to be prepared for it, not only for public health but to protect our strong shellfish economy. Imagine the damage that would occur to our reputation if contaminated shellfish was identified as coming from Rhode Island. People have a long memory for something like that.”

            Public awareness of the risk from harmful algae blooms was raised this year as a result of the months-long red tide in Florida, which killed fish and marine mammals and sickened many people. It was the result of a bloom of a plankton species that produces a toxin called brevetoxin, causing neurotoxic shellfish poisoning in people who eat infected shellfish.

            What triggers the algae to bloom is what Leibovitz calls “the $60,000 question. A lot of people are studying it, including some at the University of Rhode Island, and there are a lot of theories behind it, but there’s nothing conclusive. There’s speculation that the cleaner bay means that the harmful species don’t have the competition that they used to have, but that hasn’t been proven,” he said.

            The bloom of harmful algae in Narragansett Bay in 2016 and 2017 led Rhode Island Sea Grant to fund research to try to answer some of the questions raised by the bloom. Researchers from URI and elsewhere are investigating whether bacteria that accompany the plankton may influence the amount of domoic acid produced; whether nitrogen from the sediments may fuel the blooms; and whether nutrients from outside the bay played a role.

            “The fact that we had our first harmful algae bloom doesn’t mean we’ve had our last,” concluded Leibovitz, “not with it happening every year in Maine. But now we’ll be way ahead of the curve in recognizing when there’s a problem developing.”

This article first appeared on EcoRI.org at November 23, 2018.

Bird feeders attract bird eaters

            As much as I love wildlife documentaries on television, I always get queasy when they focus on predators like lions and hyenas.  I love learning about the life cycle and behavior of these amazing creatures, but I have a difficult time watching as one beautiful animal catches and tears apart another beautiful animal.

            Yet it’s not just on TV that I watch this happen. It happens all the time around my bird feeders in my backyard, too.

            We often think of bird feeding as a hobby that benefits the birds. And it is.  But some of the birds that it benefits are hawks that feed on other birds. That’s because some hawks have discovered that active bird feeders – with their unnatural abundance of wildlife – are an easy place to find a snack. 

            Occasionally when I glance out the window at my feeders to see who is about, there is an

Cooper's hawk at a bird feeder (H. Gilbert Miller)

unusual scarcity of birds. And the birds that are visible often look like miniature statues, frozen in place for long minutes at a time.  It’s during these tense moments that I know a hawk is nearby.

            It’s usually a Cooper’s hawk, whose narrow wings and long tail enable it to maneuver quickly through the forest and capture fast-moving prey like songbirds. And their affinity for small birds is why they appear at bird feeders so often.

            Glancing out my back window last week, I saw a burst of motion out of the corner of my eye. Appearing as if out of nowhere, a Cooper’s hawk swooped over the roof and dove at my feeders like a stealth bomber.  In that brief moment, the congregating songbirds were forced to make a life or death decision – should I fly away and hope to outrun the intruder, or should I freeze in place and hope it doesn’t see me.

            Those that froze made the better decision.  A male nuthatch stopped in its tracks on the trunk of a maple tree, head pointed downward like he was about to tumble to the ground. A like-minded downy woodpecker was perfectly positioned on the underside of a branch and out of view of the marauding hawk.  And a tufted titmouse appeared to me to be in full view but was ignored or unnoticed by the hawk.

            The rest of the birds that had been at the feeders took off in a storm of feathers and alarm calls, probably hoping that the hawk was homing in on one of the others.  A flock of goldfinches at the thistle feeder flew away en masse to confuse the hawk in a tornado of yellow and black bodies. But one goldfinch reacted just a little slower than the others. That’s the bird the hawk targeted, and that’s the bird the hawk ate for breakfast.

            I know that many people are uneasy when a hawk is seen around their feeders, and they want to discourage the predators from visiting. But hawks have to eat too, and they play an important role in the food chain by consuming the ill and injured. So it’s better if we simply appreciate the opportunity to get a close-up look at wildlife doing what wildlife does. Like when we watch those public television documentaries.

            It was about ten minutes before the nuthatch and the woodpecker and the titmouse felt safe enough to move again.  And soon after, the goldfinch flock returned to the thistle feeder. To them, it was just another day.

This article first appeared in the Independent on November 15, 2018.

Upper bay fish survey yields surprising results

            Due to the historically degraded water quality in upper Narragansett Bay, the fish that spend all or part of their lives there have seldom been studied. But as improvements have been made to the wastewater treatment plants in the area and the water quality has improved in recent years, more and more recreational fishermen have been observed reeling in a variety of fish species.

So The Nature Conservancy teamed with the Rhode Island Department of Environmental Management to conduct a baseline study of fish found from Conimicut Point in Warwick to the Pawtucket boat ramp on the Seekonk River. And the results have been somewhat surprising.

William Helt, a coastal restoration scientist at the Rhode Island office of The Nature

Conservancy who is leading the project, said the survey is an effort “to learn what fish are using that area and what the residence times are for those species. We want to get a gauge for how these sites compare to other areas in Narragansett Bay that are considered the healthy parts of the bay.”

Once a month from May to October, Helt and a team of scientists and volunteers visit 12 coastal sites, including Gaspee Point in Warwick, Sabin Point in East Providence, and Stillhouse Cove in Cranston, to survey for fish.

Using a beach seine net – a 130-foot long net with weights at the bottom and floats on top – one member of the research team holds an end of the net on shore while a boat deploys the rest of the net and drags it in a semi-circle back to shore. Any fish collected are counted, identified and released.

“We’re looking at the estuary as a nursery habitat for juvenile fish, so most of the fish we’re catching are about the length of your finger,” Helt said.

The researchers also used fish pots – similar in size and design to a lobster trap – to target larger fish like black sea bass.

While the data has yet to be analyzed or compared with the results from similar surveys in the lower bay and South County’s salt ponds, Helt said they have captured large numbers of bait fish like silversides, mummichogs and killifish. One day at Sabin Point they captured about 140,000 menhaden at one time.

“That means there’s a lot more fish utilizing the upper bay than we thought,” he said.

The net catches juvenile fish popular among local anglers as well, like tautog, winter flounder and scup. And at the mouth of the Seekonk River it collected freshwater species, including white perch and bluegill. It even caught some unexpected southern species like pufferfish and pipefish.

“We haven’t caught as many scup as we thought we would,” Helt said. “They might tend not to favor the close-to-shore habitat that we’re sampling. But we see so many people fishing for scup that we thought we’d catch more.”

Helt would have preferred that the study had started several years earlier to detect how fish populations changed as water quality improved, though he anticipates continuing the project for many years in order to assess changes to fish populations due to warming waters and further improvements to water quality.

The project may also get extended beyond the May-to-October time frame of the first two years.

“That’s when juvenile fish activity is highest; most migrate out of the estuary by October or November,” Helt said. “But we’re seeing plenty of fish in May and October, so we’ve thought about extending it for a couple extra months.”

The data the scientists have collected so far has already got them thinking about habitat improvements that could be made in the upper bay to accommodate even larger numbers of young fish.

Assuming that permits can be secured from the Rhode Island Coastal Resources Management Council and other agencies, Helt said that The Nature Conservancy and DEM anticipate deploying 80 to 100 “reef balls” – four-foot diameter concrete structures with holes in them – just beyond the Sabin Point fishing pier.

“The reef balls tend to aggregate fish,” he explained. “They eventually get fouled with colonizing organisms that provide a food base for juvenile fish, and they provide structure for small fish to hide in. We hope they’ll improve that critical life stage of juvenile fish and attract sport fish that people like to catch.”

The reef balls will likely be deployed in 8 to 10 feet of water just beyond the casting range of recreational fishermen.

The fish survey results may also lead to efforts to improve salt marsh habitat, which also plays an important role in nurturing juvenile fish.

“And in the salt ponds we’ve been studying the use of oyster shell reefs to improve fish habitat. We might do a similar project in the upper bay,” Helt said. “But we’ve got a lot of hurdles to overcome between now and then. That’s a long-term goal.”

The fish survey and subsequent habitat restoration projects are being funded by the U.S. Fish and Wildlife Service’s Sport Fish Restoration Program.

This article first appeared on EcoRI.org on November 2, 2018.