New Research Published on Leatherback Sea Turtle Migrations

Migrating between their tropical breeding grounds to more temperate feeding grounds, leatherback sea turtles frequent New England during the late summer/early fall months. They can travel thousands of miles to come and forage on the abundance of jellyfish found floating in our coastal waters.

We still don’t fully understand exactly how these giant sea turtles travel such great distances, but not for lack of trying. Scientific research has demonstrated that leatherbacks can rely on a variety of cues, such as topographic features, currents, chemosensory signals, and magnetic orientation. In a paper published last week on leatherback sea turtle migration through the North Atlantic subtropical gyre, researchers were able to narrow down the possible strategies.

Dodge et al. tracked the migration of fifteen leatherback sea turtles off of the Massachusetts coast. While traversing the North Atlantic subtropical gyre , the individual sea turtles followed remarkably similar routes, all oriented to the south-southeast.

So, how do they do it? The waters of the North Atlantic subtropical gyre are too deep and the currents too weak for the turtles to rely on any topographical or hydrodynamic cues, and a sea turtle’s poor eyesight rules out a reliance on visual cues.

Previous lab experiments have demonstrated a sea turtle’s ability to use the Earth’s magnetic field like a compass, and Dodge et al. observed that leatherbacks spend more time on the surface during the day than at night. Based on these observations the researchers concluded that leatherbacks likely rely primarily on cues from the earth’s magnetic field and the sun’s orientation.

Dodge et al. hope that their findings will support further investigation into sea turtle migration patterns and the role played by magnetic and solar cues.

You can read more about this story in the Boston Globe.

Citation: Dodge KL, Galuardi B, Lutcavage ME. 2015 Orientation behaviour of leatherback sea turtles within the North Atlantic subtropical gyre. Proc. R. Soc. B 282: 20143129. <>

A Whole Lot of Snow

As we dig ourselves out of the third major snowstorm of the season (…or of the last three weeks), the general sentiment seems to be that spring cannot come soon enough. Even as a native New Englander, there is only so much hot chocolate that can make up for this much snow. Now, what would you do if it snowed every day? I think at that point we’d all be ready to move to the tropics.

Well, this is exactly what happens in the ocean in a phenomenon known as marine snow. Okay, maybe it’s not exactly the same—frozen flakes of water aren’t swirling through the water column. Marine snow is the broad term for organic matter that is continuously falling from the surface waters to the deep sea. It earned the name “marine snow” because it actually looks like fluffy white snowflakes.

Individual particles in the water column stick together and form marine snow. The exact composition varies from aggregate to aggregate, but it generally includes decaying animals, fecal matter, inorganic materials such as silt, and tiny microbes, such as algae and bacteria, that colonize and feed on the snow. As particles join and fall off, each aggregate of marine snow is continuously reorganized.

Phytoplankton performing photosynthesis are responsible for nearly 50% of Earth’s primary production, but since these microscopic organisms are only found in the euphotic zone (the first ~200m), scientists were long curious about how food reached organisms in deeper waters. The biological activity occurring in these surface waters produces marine snow, and the constantly sinking matter is an important food source for deep-sea animals that otherwise would not have access to life’s necessary nutrients. One study found that increased marine snow volume due to tidal changes in the Gulf of Maine increased benthic blue mussel feeding activity by as much as 40%.

The sinking rate of marine snow is largely dependent on the size of the aggregate and is facilitated by marine organisms in the water column. The larger the snowflake, the more quickly it falls. Zooplankton ingesting and subsequently releasing marine snow speed the process along or else it would take years for marine snow to reach the deep-sea. Scientists use sediment traps to research the falling marine snow, and research shows that it can fall as quickly as 29m per day.

Any snow that is not eaten by deep-sea organisms eventually falls to the seafloor. It is estimated that 815 million tons of carbon reaches the seafloor every year—that’s a whole lot of snow! Not all of it stays there, though, as deep-sea organisms shovel some back into the water column where it continues to cycle through the food chain. The organic material that does remain on the seafloor adds to a layer of “ooze” that makes up much of the ocean sediment and accumulates about six meters (20ft) every million years.

So, if ocean productivity depends on it, maybe snow everyday isn’t so bad.


Image via NOAA Ocean Service.

Massachusetts Releases the MA Ocean Management Plan 2.0 – Leading the Nation in Comprehensive Ocean Planning and Management

In 2008, Governor Deval Patrick signed the landmark first-in-the-nation Oceans Act mandating the state to develop and implement a science-based comprehensive ocean management plan to protect ocean wildlife and habitat and promote sustainable use of the ocean and its resources.  The following year, the Executive Office of Energy and Environmental Affairs (EOEEA) issued the MA Ocean Management Plan—the first comprehensive ocean management plan in the United States.  The Oceans Act requires the ocean plan to be updated every five years to ensure that the plan adapts as new information and science develop, policy goals evolve, and underlying conditions change (e.g., due to the effects of climate change).

Hence, in early January 2015, Massachusetts issued the 2015 Massachusetts Ocean Management Plan.  Major highlights of the revised plan include updates to the plan’s science and data foundation, identification of preliminary offshore renewable energy transmission corridors, establishment of standards for offshore sand and gravel extraction for beach renourishment, and a schedule for ocean development mitigation fees.

In the works since 2013, the Massachusetts Office of Coastal Zone Management (CZM) completed the revised plan with assistance from a 17-member Ocean Advisory Commission and a nine-member Ocean Science Advisory Council. CZM also convened six technical work groups focused on habitat, fisheries, sediment resources, recreational and cultural services, transportation and navigation, and energy and infrastructure. Incorporating information generated by the work groups, the 2015 plan updated the scientific and data foundation of the plan and further refined the designated habitat and wildlife protection areas. Over the next five years, resource managers can use this data to make responsible and scientifically sound decisions about how we use and manage the Commonwealth’s ocean waters.

Addressing the opportunity for clean renewable offshore wind energy, the 2015 plan identifies preliminary transmission routes to bring electricity from the two federal wind energy areas off the southern coast of Massachusetts and Rhode Island to landside grid tie-in locations. The Commonwealth expects to conduct further scientific study of these preliminary routes before any final delineation.

The 2015 plan also proposes new environmental standards for offshore sand/gravel extraction—a potential new and controversial use of the state’s offshore public trust resources—to mitigate increasing coastal erosion due to sea level rise and increased storm intensity caused by global warming. To guide the Commonwealth’s continued deliberation about offshore sand extraction, the Ocean Plan provides for the appointment of an Offshore Sand Task Force to provide guidance and advice to the Commonwealth about this issue.

Lastly, the plan, as required by the Ocean Act, establishes a schedule for ocean development mitigation fees to be banked in the state’s Ocean Resources and Waterways Trust and used for planning, management, restoration, or enhancement of marine habitat and uses.

Perhaps the most important aspect of the revision process was the opportunity for extensive and ongoing public and stakeholder participation through hearings and workshops held across the state. This demonstrated the kind of transparency and engagement that is possible—and necessary—in effective decision-making regarding our ocean resources.

To be effective, ocean plans need to be living documents that evolve with new information on and scientific understanding of our ocean environment.  Planning like this will start bringing the benefits of comprehensive ecosystem-based ocean planning closer than ever and none too soon given the already-measured impacts of climate change. Bravo to Massachusetts for putting this principle in motion in the 2015 Ocean Plan and for its continued leadership in ocean planning and management!

Deep Sea Corals Deserve Protection

In a video from The Pew Charitable Trusts, coral expert Dr. Les Watling describes the important role that deep sea corals play in the Atlantic and why they need protection.

Deep sea corals are a recent discovery for many people, and scientists are discovering new species on nearly every expedition.

Unfortunately, the Atlantic deep sea corals, along with the communities they support, are under threat from commercial bottom trawling and other harmful fishing practices. Efforts are currently underway in the Mid-Atlantic to protect deep sea corals through a proposed amendment to the Mackerel, Squid, and Butterfish Fishery Management Plan.

New England officials in collaboration with those along the east coast have already signed a Memorandum of Understanding to protect Atlantic deep sea corals. This is simply an agreement to promote coral conservation. It is the hope that the proposed Mid-Atlantic amendment will urge New England officials to consider something similar.

Image courtesy of NOAA Okeanos Explorer Program.

Atlantic Treasures of the Deep

New England is home to beautifully diverse deep sea coral communities. Last fall, a team of scientists aboard NOAA’s Okeanos Explorer launched an ROV to survey the deep sea Atlantic canyons and seamounts where these corals can be found.

At the Block Canyon, just 100 miles off of Rhode Island, you can see dense populations of a variety of coral species, some even unique to the specific canyon and yet to be seen elsewhere. This habitat and many like it play host to a wide range of species from shrimps and worms to sharks and swordfish, and researchers continue to find more species as they explore new areas.

The video below was filmed during the expedition. In it you’ll see breath-taking views of the deep sea corals as well as footage displaying how the different marine species living in these special environments interact with the corals and each other.


Video and image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014.

Happy New Year!

Thank you so much for supporting New England Ocean Odyssey and helping to spread word about the beauty of New England’s ocean! We look forward to sharing more with you in 2015!

Here are some of our most read posts from 2014:

Originally image submitted by Macdyver via our Flickr page.

The Feds Have Spoken: New Rules for Gulf of Maine Cod

In August, NOAA scientists conducted a Gulf of Maine cod stock assessment. They discovered that the spawning biomass, or the breeding population, was only three to four percent of its target level—the lowest it has been in 40 years. The strength and viability of a fish population depends on its ability to reproduce. With such a low percent of the needed breeding population, this seemed unlikely for Gulf of Maine cod—the fishery had collapsed.

This announcement left scientist and fishermen butting heads about the accuracy of the assessment and the appropriate next steps to take. And since then, we have been waiting for regional and/or federal regulators to announce a plan of action to address this crisis. Three months later, we have finally received word of an interim emergency action plan.

On Monday, November 10 the National Marine Fisheries Service (NMFS), the federal agency responsible for maintaining our ocean resources and habitats, issued its interim measures in response to the Gulf of Maine cod fishery collapse. The responsibility of issuing emergency action for the remainder of the fishing year was handed off to NMFS after the New England Fishery Management Council (NEFMC) failed to complete the job itself.

NMFS addressed the crisis with two specific goals in mind: provide spawning protection and minimize overall take. They also wanted to act as quickly as possible. The measures which will be in effect from November 13, 2014 to May 15, 2015 include:

  • Rolling area closures to protect spawning and high aggregation areas based on historical catch locations
  • Commercial fishermen are limited to a 200 pound catch of cod per fishing trip
  • No recreational fishing for cod—all cod caught must be thrown back to the sea
  • Increased gill net use restrictions
  • Vessels are restricted to fishing in only one Gulf of Maine management area per trip

While it was the hope of some that NMFS would prohibit cod fishing all together, the measures do get at one of the most important aspects of proper fisheries management: habitat protection.

For fish populations, cod in particular, to thrive and be able to withstand fishing pressures, protecting spawning areas is extremely important. Fishermen, many with a lifetime of experience, know exactly where fish congregate and where they will be able to find the most valuable catch. This means however that too often the fishermen target the largest cod. Scientists have discovered that a fish’s fecundity increases with age and size, a theory that is termed the BOFFFF (Big Old Fat Fecund Female Fish) hypothesis. These large cod are the reproducing females that are responsible for keeping population numbers high. Protecting spawning areas is an effort to protect these large females, and therefore ensuring the continuation of a strong population.

NMFS importantly recognized the significance of habitat protection and made a point to not change any existing closure programs in the Gulf of Maine. It had been feared by some that some that these areas, one being Cashes Ledge, would be reopened in order to offset the new rolling area closures implemented through the interim measures. Fortunately, this did not occur.

The overall incentive of the emergency measures was for fishermen to avoid cod at all costs. These are strong measures that they will likely have major impacts on fishermen in the New England area; however, they still may not be enough to turn the cod crisis around. For now, we will just have to wait and see.

The video below provides a simple explanation of how NOAA Fisheries conducts fishery stock assessments (although they are anything but simple), using the Pacific hake fishery as an example.

Hot Rods of the Sea: The Dolphins of New England

Feature photo: October 13, Common dolphin jumping a boat wake in the Atlantic Ocean. Artie Raslich/Gotham Whale 

The Gulf of Maine is traversed by many species of marine mammals, from soulful harbor seals to the greatest of whales, either as local residents or tourists on their breeding and feeding voyages. Among the most charismatic of all are dolphins. Besides spotting them from whale-watching boats, how much do you actually know about New England’s native dolphins?

“When people think of dolphins, they think of tropical animals,” says Brian Sharp, stranding director for the International Fund for Animal Welfare, located in Yarmouth Port on Cape Cod. “But you’ve really not seen a dolphin until you’ve seen one of the species endemic to New England waters.”

The two species of dolphin most frequently sighted around Cape Cod Bay have one thing in common: their markings look like custom paint jobs. And although striped dolphins, Risso’s dolphins, and the occasional bottlenose will sometimes pass through, it’s these two species of streamlined wave-riders that New Englanders most often spy skirting the edge of the continental shelf.

Common Dolphins (Delphinus delphis)

Photo credit: NEFSC
Photo credit: NEFSC

At 6 to 7 feet long and a svelte 165 to 300 pounds, common dolphins are like “wide receivers” in build, says Tony LaCasse, media relations director of the New England Aquarium and a longtime dolphin rescuer. Even when stranded, common dolphins are communicative, chattering to the other members of their pod through clicks, whirrs, and whistles. Rescuers will often point them towards each other in order to reassure them. They are dark grey and tan with white countercolored bellies, an hourglass shape on their side, and a stripe from their eye to their mouth giving them a masked appearance. They have a long rostrum, or snout.

Atlantic White-Sided Dolphins (Lagenoryhnchus acutus)

Photo credit: NASA/GCMD
Photo credit: NASA/GCMD

Even salty, seasoned boat captains describe Atlantic white-sided dolphins as “beautiful.” These cetaceans sport natural detailing of bold white and silver patches on their sides, with a yellow or tan stripe that leads to their tail. At 7 to 9 feet long, and weighing in at more than 500 pounds, they are “girthier” than common dolphins, a look accentuated by their short rostrum. LaCasse compares them to “linebackers:” brawny, husky, and stoic while awaiting rescue at the beach

Most dolphins skim the continental shelf and shelf edge, swimming closer to the coastline if they are hot on the trail of prey such as a school of herring, hake, mackerel, smelt, or anchovies.

Unfortunately, coming near to shore makes dolphins vulnerable to running aground. It’s really impossible to talk about dolphins in New England without giving attention to strandings. Knowing how this phenomenon occurs can help us understand even more about our endemic dolphin species.

Mass strandings in New England have happened longer than humans can remember. Cape Cod Bay, a hooked sandbar with a gently sloping shore, is a notorious trap for dolphins. Anyone who has combed the beaches of the Cape knows that when the tide goes out, it runs out far and fast—so if you are a dolphin who has pursued your prey close to shore, that shallow beach profile with its hidden sandbars can leave you high and dry before you even know what’s happening.

Along the New England coast, “as far as we know, the commonest mass strandings are behaviorally driven, without a human cause,” says Michael Moore, Director of the Marine Mammal Center at Woods Hole Oceanographic Institution. Dolphins, the highly social animals that they are, may follow a sick lead animal inland. Even healthy lead animals can have their echolocation disoriented by mucky water caused by a turn of the tide, or the cloudy aftermath of a nor’easter.

Once dolphins are stranded, time is of the essence in a rescue. Gravity on land presses hard on marine mammals whose skeletons have not evolved to resist its force and protect their internal organs (seals are built to spend significant periods on land, but not so cetaceans). They can suffer significant internal trauma if out of the buoyant salt water for too long. Also, the hot sun can burn dolphin skin in summer, and frostbite can singe it in the winter. There is little temporal margin for error if dolphins are going to be viable again back at sea.

Mass dolphin strandings (from 2 to 20 individuals) occur most often in the winter, from December through April. With the lack of daylight on short winter days, the Northeast Regional Stranding Network monitors and patrols beaches in order to stay ahead of a potential crisis.

Imagine a stranding like a military triage situation. The Cape’s tidal flats can go out a long way, so a dolphin might be stranded as much as a mile from the road. They might be in three feet of tidal mud, or beached on a sand bar far from the water’s edge. Rescuers have refined the use of all-terrain dolphin carts, stretchers with cut-out holes for pectoral fins, and transport trailers that are enclosed and lined to make rescue faster, more efficient, and less traumatic. Even with all that technology, it still can take six people to carry and load a slippery, unwieldy dolphin, so rescuing is muddy, strenuous, and emotional work!

Rescued dolphins are tagged and then released from Herring Cove or Race Point in Provincetown, MA where there are fast drop-offs into deep water. The Provincetown Fire Department sets up lights on the beach to aid rescuers, and trained response volunteers in drysuits walk the dolphins out into the water.

The satellite tags reveal that after a day or two of getting their bearings, even single dolphins usually find their way back to the pod. They will link up with other released dolphins in their family group and then travel together, often heading out towards Georges or Stellwagen Bank… staying well clear of land!

While little can be done to prevent geographically-caused mass strandings, you can support your local rescue network to make sure that stranded animals have a viable chance at survival. Single animal strandings often caused by illness, injury, or entanglement in fishing gear are more complex. In that case, advocating for responsible, sustainable fishing practices will help dolphins and other pelagic species avoid becoming bycatch casualties.

Dolphins are very much residents of New England waters, and there are more of them out there than we might realize: “When you see four or five dolphins at the surface,” says Brian Sharp, “it can be an iceberg effect: that really is a small portion of the number of animals actually around you, below the water and beyond your vision.”

Hopefully what you have learned here will help expand your vision so that you will see our endemic dolphin species even more clearly!

If you find a dolphin stranded south of Boston, please telephone IFAW’s stranding hotline at 508-743-9548. From Boston on north, please dial the New England Aquarium’s Marine Animal Hotline at 617-973-5247. For entanglements or by-caught cetaceans, please call the Provincetown Center for Coastal Studies at 1-800-900-3622.