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.

White Sharks Get Top Billing at Chatham Benefit Lecture

Hypnotic, elusive, and highly charismatic…. Even at a benefit lecture by a world-renowned photographer and a media-savvy scientist, undoubtedly the great white shark was the star.

Everybody wants to know about this A-lister among fish that makes its seasonal vacation home just off New England’s coasts. So like a feeding frenzy of fans, a sold-out, starstruck crowd packed the Chatham Bars Inn for a joint presentation by acclaimed National Geographic photojournalist and New England Ocean Odyssey collaborator Brian Skerry, and Greg Skomal, senior fisheries expert for Massachusetts Division of Marine Fisheries and director of the Massachusetts Shark Research Program. The lecture was a benefit for the Atlantic White Shark Conservancy.

Skerry opened the evening with “Ocean Soul,” the luminously pictorial, ever-evolving documentation of his travels covering marine wildlife all over the globe. He used a photograph of a baby shark in a mangrove nursery to begin a narration of oceanic habitat in Bimini, where ecosystems of reefs, seagrass beds, and mangrove stands interconnect. “Animals flow between all of these,” he pointed out. Skerry emphasized the absolute interdependence of life in marine habitats: “Every animal plays a role,” he said. “Everything matters.”

That interdependence, of course, includes sharks. Skerry’s global perspective set the stage for Skomal’s thrilling regional focus on sharks in New England’s coastal waters. For of the distinct great white shark populations all over the world – in the northeast and northwest Pacific, around the coast of South Africa, and the coasts of Australia and New Zealand – there is one population of great whites that loves Cape Cod. Teeming grey seal populations due to climatic shifts have over the past decade made the Cape a hot vacation spot for this celebrity predatory jet set.

The frequency and predictability of shark visits to the Cape – one shark nicknamed “Julia” returns on almost the exact same date every year – give researchers the rare advantage of access to these animals.

IMG_2123crpd
Above: Dr. Greg Skomal and his team tracking and tagging great white sharks near Chatham.

Aerial spotters help Skomal and his team locate the sharks. Once a shark is spotted, the challenge of tagging begins, with a biologist balancing on the pulpit of a boat to lance the fish’s dorsal fin with an electronic tag via an intramuscular dart. Buoys and receivers on the ocean then create transects that collect data about sharks in the area.

New technology has given researchers more access to sharks, through acoustic tags, pop-up satellite tags, and AUVs (i.e., drones) – autonomous underwater vehicles that send back revealing videos of shark behaviors.

“We know that they are dynamic and highly migratory, with complex migratory patterns,” said Skomal. “They are warm-bodied, so they can go anyplace they want. They are far more remarkable than we had ever imagined.”

But for all we have discovered about sharks, there is still so much we don’t know. “We are just getting started with studying these animals in this area,” said Skomal, who has been concentrating almost exclusively on shark research for the last six years. He invited young people fascinated by the sea to consider a career in shark science, which offers ample opportunities for exploration, such as solving the mystery of white sharks’ 800-meter-deep dives off of the continental shelf. What are they doing down there?

Skomal emphasizes the importance of sharks as apex predators for maintaining sustainable fisheries. Just like terrestrial predators picking off the sick and weak members of a herd, sharks keep fish stocks healthy by predating the less viable members of a fish school. So they are in fact allies of fishermen, being fishermen themselves!

Skomal’s research on the migratory pathways of these formidable fish could be a valuable resource for policymakers in the creation of protected areas where sharks can be safe from hunting and harassment, in order to replenish their populations so critical to the balance of a healthy ocean ecosystem. Every animal matters.

And his advice for humans sharing the water with these grand and intimidating animals? Show common sense and healthy respect. And don’t swim in the deep channels close to shore.

Feature image via Atlantic White Shark Conservancy

Mountains and Forests of New England’s Ocean

New Englanders are familiar with the mountains that mark their landscape: the Green or White Mountains in Vermont and New Hampshire, the Berkshires and Holyoke ranges in Western Massachusetts. But mountain ranges also lie beneath New England’s North Atlantic waters, and are equally diverse havens for wildlife as their terrestrial counterparts.

Cashes Ledge is one of New England’s most spectacular mountains, but it happens to be lying 80 miles southeast of Portland. This submerged mountain, known as a seamount, is composed of widely spaced peaks, pinnacles, and knolls with average depths of about 100 feet and its highest peak, Ammen Rock, rises within 40 feet of the surface.

This topography is one of the contributors to Cashes’ ecological richness; the steep angle of the slopes causes an oceanographic phenomenon called internal waves. As currents bring water against the abrupt topographic “high” of the ridge, the layers of plankton in the warmer overlying waters are driven to the bottom, as frequently as 20 times a day. These down-welling plankton layers are pulses of concentrated food that sustain bottom-dwelling organisms and fuel the entire food web.

Along with the constant circulation of nutrients by internal waves, the variety of terrains at Cashes Ledge—rocky banks and granite outcroppings, peaks, and channels, cobble and boulder fields, sand-and-gravel-covered seafloor, and soft bottom areas of mud and silt in the basins—also contributes to its intense complexity of life.

Having so many different spaces for organisms to inhabit increases species diversity. The hard, rocky substrate on Ammen Rock and other pinnacles along Cashes Ledge is home to a variety of plants and animals that vary by depth along the slopes, creating identifiable shallow, intermediate, and deep water zones.

In the shallow zone, which extends from the top of each pinnacle down to a depth of approximately 130 feet, grow forests of laminarian kelp up to 30 feet tall, shifting to shotgun kelp as the depth increases. At this depth, kelp groves alternate with aggregations of sea anemones, and both encrusting and mobile invertebrates proliferate in the profuse protection of the kelp.

In the intermediate zone, suspension-feeding invertebrates begin to predominate, and continue to the bottom of the rock slope at approximately 200-230 feet. As the slope begins to level off between 230-250 feet, the muddy bottom of the deep zone supports a biogenic habitat structure for tube worms, mud anemones, and northern shrimp.

The teeming diversity of seamount ecosystems makes them tempting to deep-sea fishing trawlers, which would drag weighted nets across the mountainous terrain in order to catch the schools of fish which congregate there to breed, lay their eggs, and grow to maturity among the sheltering crags. The rocky cobble and gravel substrates of Cashes Ledge are critical nurseries for juvenile Atlantic cod; its sandy and algal dominated areas serve as habitat for pollock eggs, larvae, and young, and its deep muddy areas are essential habitat for white hake.

The kelp forest that is a signature of Cashes Ledge is quite susceptible to human-induced harm. If stripped by mobile fishing gear or shredded by repeated impact from lines, hooks, traps, or other human influences, the tall kelp forests that grow on the Cashes Ledge pinnacles would take many years to re-achieve their former stature. The diverse ecosystem that depends upon these kelp forests could be completely altered, if not eliminated, during that period of regrowth.

Bottom trawling to catch a few groundfish is “like clear cutting a forest to catch a squirrel,” says New England Ocean Odyssey partner and renowned marine wildlife photographer Brian Skerry, who has witnessed bottom-trawled environments firsthand on his dives.

It is such a unique, valuable, and interdependent ecosystem, Cashes Ledge requires permanent protection from human impingement. As a large area comprising many different types of habitat, Cashes Ledge has much to contribute toward keeping our oceans healthy.

Help keep Cashes Ledge permanently protected by joining our petition today!

Laura Marjorie Miller writes about travel, ocean conservation, Yoga, magic, myth, fairy tales, photography, and other soulful subjects. She is a regular columnist at elephantjournal, a writer at UMass Amherst, and a travel correspondent for the Boston Globe. Her writing has appeared in Parabola and she has features forthcoming in Yankee Magazine and Seven Miles of Steel Thistles. She is based in Massachusetts, where she lives with a cat named Huck.

It Takes a Village: Life on the Bottom at Cashes Ledge

If you’re reading this post, you are probably a vertebrate. Those of us with spines and bones may find it hard to empathize with invertebrates (animals without spines), with their radically alien ways of being, frequent radial symmetry and general facelessness! But in many ways, invertebrates are the heart of ocean ecosystems, so for those of us interested in the fascinating universe of the sea it is important to understand them. And there are few better places to study invertebrate communities than one unique and now threatened special area in the Gulf of Maine.

Off the New England coast, about 80 miles due east from Cape Ann, lies Cashes Ledge: an undersea mountain range that is one of the most dynamic, and ecologically productive areas in the entire North Atlantic. Although only the most intrepid divers have seen Cashes Ledge with their own eyes, you can imagine the undersea terrain by thinking of mountains that you already know: as a multifaceted terrain of rocky peaks, banks, and channels, with a valley floor of mud, gravel, sand, boulders, and rock. This terrain supports a vibrant bottom-dwelling community of bright orange, red, and yellow sponges, sea stars, brittle and feather stars, sea squirts, sea pens, anemones, tube worms, northern shrimp, horse mussels, and sea mosses, technically known as “bryozoans.”

This colorful community is one of Cashes Ledge’s treasures, and one that is ever more in peril.

Invertebrates of Cashes Ledge. Photo by Jon Witman.
Invertebrates of Cashes Ledge. Photo by Jon Witman.

 

The variety of terrain at Cashes Ledge makes it an ideal living laboratory for studying the structure of the vibrant communities that grow along its slopes and hills. The enhanced water flow created by the topographic “ramp” of the Ledge encourages a high growth rate of invertebrates, both mobile and encrusted to their home rocks—varieties of sponges that are as yet uncatalogued, including a rare species of blue sponge that has only ever been sighted in the rock wall communities of Cashes Ledge.

Unique communities form at each depth, creating a complex and rich diversity of species. Metridum anemones gather at the tops of the ridges, sheltered by waving groves of laminarian kelp. Large urticina anemones and orange sea stars flourish in the mid-depth areas, as well as brachiopods, crinoids, ascidians, and yellow mounding sponges the size of footballs. The soft bottom is home to tube worms, pink northern shrimp, and thickets of mud anemones. Ammen Rock, the highest peak in the Cashes Ledge range, hosts large, sensitive beds of horse mussels: a “foundation species” because they provide habitat and refuge for other species.

Phakelia sponge and brittle stars. Photo by Jon Witman.
Phakelia sponge and brittle stars. Photo by Jon Witman.

The biological richness which makes Cashes Ledge so compelling for scientists to study has also drawn the attention of industrial fishing interests, which are currently lobbying to remove long-standing protections for Cashes Ledge.  Allowing bottom trawling at Cashes Ledge would rapidly deplete the remaining populations of large cod and other groundfish who are the most prolific spawners. The kelp forests, slopes and rocky terrain serve as excellent habitat and the best chance for restoring Gulf of Maine cod populations, which are now at historically low numbers.

Cod and anemones. Photo by Stellwagen Bank National Marine Sanctuary.
Cod and invertebrates. Photo by Stellwagen Bank National Marine Sanctuary.

New bottom trawling would be bad news for bottom-dwelling sea life at Cashes Ledge, because a number of the invertebrate species that grow there are particularly vulnerable to human disturbance. These invertebrates move slowly (if at all), and often have specialized reproductive cycles. If their habitat is harmed and breeding adults removed, species could take many years to recover, even longer for rarer species. Scientific estimates predict that the large, solitary sea anemone Urticina crassicornis would take 268 years to return to the community if it were removed by fishing gear.

Trawling Cashes Ledge could deplete or endanger many species that we do not yet fully know about. Cashes Ledge should be left intact as a resource for scientists, as well as a replenishment zone whose presence will sustain a recovering ocean ecosystem that will be of benefit to fishermen in the future. Trawling at Cashes Ledge is a short-term economic gamble that would cause long-term economic and environmental damage.

Cashes Ledge is a “wild offshore place that helps us understand how marine ecosystems tick,” says marine ecologist Jon Witman, who has been studying it for 35 years. “Cashes Ledge provides an opportunity to understand why biodiversity matters in an ecological sense. Unfortunately,” he continues, “we are losing marine biodiversity in the world’s oceans faster than we can study it.”

As an offshore haven far from the polluted waters of coastal habitats, Cashes Ledge warrants full and permanent protection to ensure that its intricately connected habitats and unique ecosystem can continue to serve as a reservoir of diverse ocean wildlife, a replenishment zone for sustainable fish stocks, and an open ocean laboratory for scientific research. Please add your voice to those calling for the protection of Cashes Ledge.

Laura Marjorie Miller writes about travel, ocean conservation, Yoga, magic, myth, fairy tales, photography, and other soulful subjects. She is a regular columnist at elephantjournal, a writer at UMass Amherst, and a travel correspondent for the Boston Globe. Her writing has appeared in Parabola and she has features forthcoming in Yankee Magazine and Seven Miles of Steel Thistles. She is based in Massachusetts, where she lives with a cat named Huck.

Feature image credit: Josh Cummings

Life on the Line: North Atlantic Right Whales Need Cashes Ledge

One of the favorite feeding grounds for an endangered whale is, well, an endangered ledge.

A Fertile Forest

Cashes Ledge, an underwater mountain range located 80 miles east of Cape Ann in the Gulf of Maine, teems with wildlife. As with many seamounts, the Ledge’s steep ridges and deep basins, as well as its kelp forests, create an underwater landscape ideal for marine animals to hide, hunt, and spawn.

Because of this abundant ecology, Cashes Ledge is looked upon with increasing desire by commercial fishing interests who want to be able to bring in bottom trawlers to get at the diverse populations of finfish who feed and breed there: fish like cod, haddock, hake, and halibut.

But humans aren’t the only ones who want to fish at Cashes Ledge: the richness of the indigenous ecosystem attracts ocean predators like migrating bluefin tuna, sharks, and yes, whales—all of whom depend on ecosystem of the Ledge for food.

With its abundant upwellings of plankton, Cashes Ledge is an important feeding stop for endangered humpback whales during their seasonal migration in the spring and early summer, and for even more critically endangered North Atlantic right whales, who feed at the Ledge during the summer and fall. The Ledge also attracts smaller, swifter minke whales, who dive in the slicks of calm water between the internal waves, as well as harbor porpoises.

Internal Waves

Right whales use their long black baleen plates, as long as a person is tall, to strain tiny zooplankton and krill out of the water. And there is plenty of plankton to be had at Cashes Ledge! The steep topography and stratified water column around Ammen Rock, the highest peak in the Cashes range, generates an oceanographic phenomenon known as internal waves, which bring plankton-rich waters into a highly dynamic circulation. The force of the internal waves pushes the warm water from the upper levels of the water column against the peaks and slopes of the ledge, driving it down to mix with colder depths, delivering a rich supply of plankton to the bottom. The warm water rises back to the upper photic zone where it is pushed along the ledge and forced downward again. This process, which happens as many as 20 times a day, results in the regular circulation of nutrient-rich water within the water column, and an area of high productivity and energy.

A Wayfaring Whale

For all their size and might, there are fewer than 500 North Atlantic right whales alive on Earth today. Right whales are sometimes referred to as “urban whales,” as their migratory pathways carry them along coastlines busy with human commercial activity. Because they sift their food slowly at the water’s surface, they are vulnerable to injury or death from ship strike and entanglement in fishing nets.

Calving female right whales migrate south along the Atlantic coast of North America to bear their young in warmer southern waters, but in general, rights love to move about the Gulf of Maine in a regular pattern, looking for where the food supply is best. “Cashes Ledge is one of the stopping-off places for North Atlantic right whales and humpbacks, both endangered,” says Stormy Mayo, Senior Scientist and director of right whale habitat studies at the Provincetown Center for Coastal Studies. “Cashes Ledge is notoriously rich and doubtless plays in important role in the rich processes of the Gulf of Maine.”

Whales have always been inextricably linked to their food: find one, and you find the other. Like all other animals, they go where the food is. In Moby-Dick, the crew of the Pequod locates right whales through the presence of “brit” — yellow swarms of copepods on the water.

An Interdependent Symphony

With fewer than 500 individuals left on the planet, every North Atlantic right whale is essential to the survival of the species. Protecting whales means preserving the ecosystems in which they can be nourished and healthy to survive the hazards of migration along highly-trafficked waterways.

One important way to protect animals is to keep the habitat that supports them intact and thriving. Which is why CLF is asking fisheries managers to permanently protect this special place. You can help by signing their petition.

Defending Cashes Ledge from trawling will benefit not only the gigantic right whales, but also a host of interdependent species, including cod, bluefin tuna, and other iconic “New Englanders.” CLF seeks to make the current industrial fishing restrictions on Cashes Ledge permanent, to ensure that this unique and vital habitat is fully restored and thriving to support generations of whales to come.

Laura Marjorie Miller writes about travel, ocean conservation, Yoga, magic, myth, fairy tales, photography, and other soulful subjects. She is a regular columnist at elephantjournal, a writer at UMass Amherst, and a travel correspondent for the Boston Globe. Her writing has appeared in Parabola and she has features forthcoming in Yankee Magazine and Seven Miles of Steel Thistles. She is based in Massachusetts, where she lives with a cat named Huck.