Friday, April 22, 2016

Big Brother for birds

            If you feel as if you’re being watched while walking at some of Rhode Island’s beaches and wildlife refuges, you’re not alone. The 40-foot radio telemetry towers constructed at Trustom Pond, Sachuest Point, Napatree Point and Block Island’s Southeast Light – each topped with six antennae to enable monitoring in every direction – have certainly raised their share of questions. Conspiracy theorists might assume that they are part of a covert government operation to keep track of the private lives of ordinary Rhode Islanders. But they’re not invading anyone’s privacy. Not, unless you’re a bird.
            The towers are part of a network that runs from the Canadian Maritimes to North Carolina that allows biologists to monitor the migratory movements of birds and bats through the region. The scientists in charge of the Rhode Island towers are especially interested in the offshore movements of several species of rare birds that live along our coast. The data they collect is sought by the Bureau of Ocean Energy Management to help it make appropriate siting decisions about future offshore energy facilities. But it’s also providing an intriguing look into the lives of our feathered friends.
Pam Loring, right, attaches nanotag to oystercatcher. 
            Pamela Loring, who got her start in ornithology while studying at the University of Rhode Island and is now nearing completion of her doctorate at UMass, monitors the data collected from 20 towers located between Cape Cod and Long Island. In the last two years, she has captured more than 200 common and roseate terns, piping plovers and American oystercatchers and attached tiny “nanotags” to their backs with glue. The tags consist of a light-weight, digital transmitter that can be detected when the birds fly within about 20 miles of one of the 250 towers in the United States and Canada.
            Most of the tagged plovers and oystercatchers have already arrived back in Rhode Island from their wintering grounds in the South, and the terns should start showing up any day now. So Loring is looking forward to collecting and analyzing another year of data. She has already learned some surprising details about the birds.
            The terns, for instance, repeatedly move back and forth between Cape Cod, Buzzards Bay, Rhode Island and Long Island at all times of the day and night throughout the breeding season, something that previous aerial and boat-based surveys of bird populations could not reveal. And because Loring knows where each bird was tagged, she is discovering that birds from different nesting colonies move through the area in different ways.
            She was also surprised to find that many piping plovers depart on their southbound migration by flying far offshore rather than hugging the coast, as most biologists believed. One bird flew straight south from Cape Cod beginning at 7 o’clock one evening and was detected by a tower in southern New Jersey eight hours later. The Rhode Island plovers took alternate routes – some started out heading south between Block Island and Montauk Point while others traversed Long Island Sound before turning south.
            Loring and colleagues from URI and the U.S. Fish and Wildlife Service will be capturing additional birds this spring and summer to affix nanotags to them in hopes of collecting even more data in the future. So piping plovers seeking to keep their travel plans a secret should probably avoid suspicious scientists for the next couple months.

This article first appeared in The Independent on April 22, 2016.

Thursday, April 21, 2016

Invasive crabs changing ecology of Narragansett Bay

            Niels-Viggo Hobbs has spent a great deal of time in recent years exploring tide pools and the rocky shoreline of Rhode Island, and he said that the ecology of the shore has changed dramatically in the last two decades due to one relatively recent invader: the Asian shore crab.
            “Twenty years ago if you went to the rocky shore and turned over rocks, you would have found mostly one or two species of native crabs,” said Hobbs, a doctoral candidate at the University of Rhode Island. “But within a year of the Asian shore crab showing up in Rhode Island in 1998, if you turned over those same rocks, you’d have something like 20 or 30 Asian shore crabs.”
Asian shore crabs by Niels-Viggo Hobbs
            Asian shore crabs aren’t large – their shells are typically an inch or less across – but they reproduce quickly and are more tolerant of cold and being out of the water than the region’s native crabs.  Hobbs said that a one-meter area that may have harbored a dozen native crabs two decades ago now harbors hundreds of Asian shore crabs.
            “They eat whatever they can get their claws on, and they reproduce like crazy, so they have a lot of mouths to feed,” Hobbs said. “But they also become food for other marine life as well.”
            Lobsters are one such species for which the Asian shore crab is a double-edged sword. While the shore crabs may consume large quantities of larval lobsters, the crabs are also probably eaten in large numbers by adult lobsters. Commercially important fish, such as black sea bass, also benefit from the availability of large quantities of Asian shore crabs.
            Hobbs said the green crab, which is the second most abundant crab species on Narragansett Bay shores, is also an invasive species. But it arrived in the region in the ballast of ships about 200 years ago – long before scientists paid much attention to crabs -- so it is difficult to know how its arrival may have affected the marine environment.
            “The one thing we know happened after the arrival of green crabs is that snail shells got thicker and tougher,” Hobbs said. “They were apparently really good at cracking open snail shells, so the snails evolved thicker shells.”
            The focus of Hobbs’ research is on the cost of aggression among crabs of the same species – for instance, how does fighting among themselves affect how quickly they grow and mature, how likely they are to be injured or die, and other factors. So he put pairs of crabs in glass jars for what he called “crab fight club” to observe how aggressively they behaved.
            He found a great deal of variation. Spider crabs, which have the smallest claws, exhibit almost no aggression at all, whereas the rare lady crab is just the opposite.
            “Those results likely correlate with how abundant they are in the wild,” explained Hobbs. “Hundreds of spider crabs can be piled up in one small area, and if they were as aggressive as lady crabs then they would just kill each other.”
            What is most interesting to Hobbs is that Asian shore crabs aren’t all that aggressive. Since they don’t fight among themselves, they can rapidly build up large populations, making it difficult for native crabs to share the same habitat.
            “One of the major mechanisms helping the Asian shore crab succeed is that they’re not all that aggressive to their own species,” Hobbs said. “They’re incredibly tolerant of other Asian shore crabs, allowing them to be in such abundance that they can act like a wall keeping other species from moving into an area.”
            Has the invasion of Asian shore crabs and green crabs made the Narragansett Bay ecosystem unhealthy?
            “I can’t say it’s a less healthy ecosystem; it’s just a different ecosystem than it would have been without them,” Hobbs said. “There could be negative ecosystem effects – in addition to outcompeting native crabs, Asian shore crabs eat a lot of mussels, so they could be having an effect on important filter feeders in the bay. But there is no evidence that they’ve had such an impact that the ecosystem changes are significantly negative. So far it’s just lower level ecological communities that have been negatively affected at this point.”

Wednesday, April 20, 2016

Starfish slow to recover from disease outbreak

            When a University of Rhode Island undergraduate student tried to conduct a research project on starfish in 2011, she immediately ran into trouble when the starfish – more appropriately called sea stars – quickly began dying. The animals first became bloated, and within a day or two they were mushy and appeared to just melt away. It was one of the first East Coast observations of sea star wasting disease, which nearly wiped out the species from the coastal environment from Maine to New Jersey.
            Five years later, sea stars are still quite difficult to find in Rhode Island waters, though it appears that the die-off may be over. Whether they are beginning to recover their populations is another question.
Common sea star photo by Bill Frank
            “I think the disease is still out there, though I don’t know how intense it is any more,” said Adam Kovarsky, who manages the Save the Bay Exploration Center and Aquarium in Newport. “We still see sea stars with related issues now and again, but it appears that the population seems to be making a slight recovery from what it was. But it’s slight.”
            Kovarsky successfully kept the disease from infecting the 30 sea stars in Save the Bay’s aquarium for about two years, but eventually the disease found its way into his facility and all of the sea stars died.
            A few years before the disease was discovered, sea stars experienced an exponential population increase in Narragansett Bay. It wasn’t uncommon for Kovarsky to pull up 300 pounds of sea stars at a time with the fishing trawl net he uses in educational programs on the water. The year after the disease struck, he caught none. Today, Kovarsky said that sea stars are still mostly absent from shoreline habitats, though they are found in limited numbers by fishermen in Rhode Island Sound and in smaller numbers in the deepest parts of the Bay.
            The population increase just before the disease struck may have contributed to the outbreak, which is not an uncommon phenomenon. Niels-Viggo Hobbs, a doctoral student at URI who studies crabs and other shoreline creatures, said that rapid population increases often make animals more susceptible to disease, and the large numbers living nearly on top of each other make it easy for diseases to be quickly transmitted throughout the population.
            “All the sea stars people are finding now appear to be healthy,” said Hobbs, “so maybe all of those that were susceptible to the disease were killed off. The population is much, much lower now, but that may be just part of a natural cycle.”
Hobbs and other experts said that most of the sea stars found in the bay in the last year have been juveniles, while adults are still rare.
            What caused the disease is still uncertain, though researchers speculate that the pathogen may have been in the water for many years and was only triggered recently when changing environmental conditions reduced the sea stars’ immunity. Researchers from URI, Brown University and Roger Williams University worked together for several years to gain insight into the cause, but they were hampered by the challenge of finding many living sea stars to study. Caitlin DelSesto, the URI student who discovered the disease as an undergraduate, completed her master’s degree last spring studying the environmental conditions that may have helped to spawn the disease outbreak.
                   "Even throughout the course of our experimentation, some stars never seemed to succumb to the disease pathology, which lends hope to the idea that their numbers could recover," said DelSesto. "We do not know for sure what has been triggering the outbreak, so it is hard to say whether this stimulus -- like higher temperatures, differences in salinity or pollutants -- is still active in the ecosystem."
            The disease isn’t confined to the East Coast, however. As many as 40 different species of sea stars from Alaska to Mexico have also been killed by what is presumed to be the same or a similar disease as the one affecting sea stars in southern New England. West Coast experts meeting about the disease in Seattle in January called it one of the largest wildlife die-offs ever recorded, with 90 to 95 percent of some populations affected. Researchers there think it may be caused by a virus that became more harmful due to warming ocean waters.
            “An outbreak like this happened here back in the 1990s, and on the West Coast there were similar outbreaks in the 70s and 80s, and every time the population came back on their own,” said DelSesto in an interview in 2013. “This one seems particularly severe, and climate change may be making it worse, but hopefully they’ll come back on their own this time, too.”

This article first appeared on on April 20.

Tuesday, April 19, 2016

Wild goose chase: Reigning in a nasty mess

            Canada geese are pooping machines. About every four minutes throughout the day they defecate, regardless of where they are and what else they’re doing. As a result, the familiar birds can be a significant cause of water quality degradation in local ponds and a messy problem for those walking at golf courses, athletic fields, suburban parks and anywhere there is plenty of grass for the birds to graze on.
            It’s a problem that the Wanumetonomy Golf and Country Club in Middletown has been fighting for years. “After the geese spend much of the winter on the course, by spring every inch of the property was covered in a blanket of goose poop,” said Curt Vannah, a board member at the club. “Early season golfers would have it caked all over their shoes.”
            Last year Vannah took on the challenge of resolving the issue for the club, eventually settling on a large orange remote-controlled device called the Goosinator that has succeeded in keeping the golf course nearly goose-free for more than a year. “Look at our golf course this spring, and compared to past years we’ve got about 90 percent less goose poop.”
But the Goosinator is not the answer for every property, in part because it’s expensive and requires someone to operate it regularly.
            That’s why Kat Zuromski is helping address the issue of nuisance geese all around Rhode Island. A biologist working for the Southern Rhode Island Conservation District, she is leading workshops to educate the public about the environmental, economic and aesthetic problems geese can cause and what residents can do about it.
            “It’s a human caused problem,” she said. “We’ve created habitat for them with our lush lawns, and people feed them, so it’s something we need to do something about. It’s not normal for geese to stick around Rhode Island year round, but now we have populations of resident geese who nest here and don’t link up with the migratory populations because the conditions here are so good.”
            Zuromski points to poor water quality as the major problem caused by too many geese, but she also says they can be aggressive, transmit diseases, and destroy crops.
            She said she hears lots of people complaining about geese, and it’s a problem that can be difficult to solve. Geese are protected by the Migratory Bird Treaty Act, so they cannot be killed without a permit. They can be hunted in season, though hunting is prohibited in many urban and suburban communities, so it is often not an option. They can be legally harassed to encourage the birds to leave an area, and in addition to the Goosinator, some golf courses have been successful at using dogs trained to chase geese.
            The method Zuromski advocates is oiling the birds’ eggs, which kills the embryo and prevents the birds from reproducing. Anyone who registers on a U.S. Fish and Wildlife Service website is allowed to oil goose eggs, but doing it just once doesn’t solve the problem.
            “It’s a long process, which is why we’re trying to mobilize communities to carry on this work,” she said. “It has to be done over the course of years to make it effective. If people carry on with these efforts, over time the resident geese may link up with migratory populations and leave. That’s the end goal.”
            Not everyone agrees that Canada geese are a problem, however.  ScottMcWilliams, an ornithologist at the University of Rhode Island who earned his doctorate studying geese, called it a problem of public perception.
            “Do we have too many geese that are resident on the landscape?” he asked. “No. There is plenty of habitat available for them, and they’re not having a negative impact on the environment from a natural science point of view. It’s a question of people’s willingness to tolerate them. We manage geese in the state in part due to public perception that they’re a problem.”
            McWilliams agrees that Canada geese are a nuisance on golf courses, turf farms and athletic fields. He also agrees that the animals can degrade water quality in local ponds.  He also doesn’t object to “additional controls” on the goose population, like efforts to oil their eggs, as long as it doesn’t affect the health of the entire goose population.
            Josh Beuth, the waterfowl biologist at the Rhode Island Department of Environmental Management, said that about 15,000 to 20,000 Canada geese winter in Rhode Island, and 5,000 or 6,000 remain here to breed in the spring and summer. Newport County has the highest density of geese in the state, due largely to the number of golf courses and agricultural fields located there, but also because of the limited hunting that takes place.
            “We have liberal hunting seasons, but in areas like Aquidneck Island where there isn’t much hunting, there’s no way to reign the population in, and it’s going to continue to expand until something else is done,” Beuth said.
            He provides residents with a packet of information with a wide range of lethal and non-lethal recommendations for controlling nuisance geese. But he also points out that geese are a valuable natural resource in the state. “Canada geese are native wildlife, so we don’t want to just get rid of them,” he said. “They have their place here. It’s just a matter of finding that balance between nature and people.”

This article first appeared in the Newport Mercury on April 19, 2016.

Wednesday, April 6, 2016

Record number of seals observed in Narragansett Bay

            Seal numbers in Narragansett Bay reached a record high in March when an informal survey conducted by volunteers from Save the Bay, the Environmental Protection Agency and the Narragansett BayNational Estuarine Research Reserve tallied 603 seals at 26 sites.  The previous record of 569 seals was set in 2011.
            Seals were observed in all parts of the bay, including a single animal hauled out on a rock just off Fields Point in Providence and 101 seals counted at Brenton Point in Newport. Participants also counted large numbers of seals at Rome Point, Coddington Cove, Prudence Island and Hope Island, each of which had more than three dozen seals in the vicinity.
            “High numbers of observed seals in the water are a strong indicator of a hospitable environment and a healthy ecosystem that provides sufficient food and other needs for marine life,” said Eric Pfirrmann, the captain of the boat used by Save the Bay to count seals. “We can attribute a strong seal population here to both a healthier bay and the Marine Mammal Protection Act of 1972, which made it illegal to kill, take or harass marine mammals.”
            The seal survey has been conducted annually since 1994, though ice and poor weather forced the cancellation of last year’s survey.  Almost all of the animals counted were harbor seals, which have been proposed to be designated as the state marine mammal of Rhode Island. A small number of gray seals were also seen.
            Pfirrmann said that despite the record number of seals in the bay this year, seal numbers have remained somewhat consistent in recent years. 
            “Seal populations fluctuate from year to year, just as environmental conditions fluctuate,” said Pfirrmann. “I feel the seal population has been relatively stable for some time now, and that the bay is probably at carrying capacity for harbor seals.”
            According to Robert Kenney, a marine mammal expert at the University of Rhode Island’s Graduate School of Oceanography, harbor seals begin to arrive in Narragansett Bay in September, reach a peak in March, and depart by the end of April. They all migrate north to the coast of Maine and the Canadian Maritimes to breed, though a small number give birth on the Isles of Shoals in New Hampshire and in Manomet, Massachusetts.
            Despite the record number of seals observed in Narragansett Bay this year, Kenney said scientists suspect that the New England harbor seal population may be declining.
            “Stock assessment surveys hint that numbers are down from their peak, maybe because they’re being pushed around by the larger gray seals, which are growing like crazy,” Kenney said. Large numbers of gray seals breed at Monomoy National Wildlife Refuge on Cape Cod.
            Seals were quite rare in Rhode Island waters prior to passage of the Marine Mammal Protection Act. The peak number of seals observed at any one place in Narragansett Bay in the 1960s was 12 at Rome Point. At that time, Massachusetts and Maine paid a bounty of $5 for every seal killed, because the animals were thought to be negatively affecting the region’s commercial fishing industry.
            “I remember hearing stories of people who would go out on motorboats to shoot seals for fun,” said Kenney.
            Despite the seemingly healthy population of seals in Narragansett Bay today, little is known about their ecology during the six months they spend in Rhode Island waters.  Kenney said it is unknown what they eat while they are in the state, so it’s impossible to determine whether there is enough food to sustain them or whether the population can continue to grow.
            One thing is certain, however. The harbor seal population that winters in southern New England has been spreading out in recent years, Kenney said. Rather than being confined to Narragansett Bay, eastern Long Island and eastern Connecticut, they are now found as far south as New Jersey.
            “We really don’t know what component of the population comes down this far,” Kenney said. “There has always been some suspicion that harbor seals in our area tend to be younger animals. Maybe the younger ones have a harder time coping with the really cold water to the north.”
            People interested in observing seals should be careful not to disturb them.
            “Anything that’s going to spook them off the rocks is harmful to the seals because it makes them waste precious energy,” said July Lewis, the volunteer manager at Save the Bay who organized the seal survey. “So be careful not to let dogs bark at them. And if you’re approaching them in a kayak or other boat, go parallel to the rocks so it doesn’t look like you’re going straight at them, which they interpret as an attack.”
            “Even if you think you’re at a safe distance,” she added, “if you see them stretching their necks or moving around, you’re too close.”

This article first appeared on on April 6, 2016.