Beyond the data: Captivating moments at Cashes Ledge

Diver Robbie Lamb of the Witman Lab at Brown University recounts his experiences diving at the unique underwater mountain range 

Our two weeks of diving, research, and filming on Cashes Ledge has come to an end. We have spent the last 14 days diving off of the R/V Tioga (via Woods Hole Oceanographic Institute), visiting sites throughout the Gulf of Maine, and making several dives per day to document marine life.

Our team of filmmakers, Brett Seymour, Luis Lamar, and Evan Kovacs, have shot incredible footage of the rich underwater communities to be found on the “Jewel of the Gulf of Maine.” We look forward to seeing their pictures and videos in the coming days.

Meanwhile, the Witman Lab (Jon Witman, Robbie Lamb, and Fiona Beltram) along with Elizabeth Kintzing of the University of New Hampshire are busy analyzing gigabytes of data on all aspects of benthic and fish communities.

The other day on one of our research dives on Cashes Ledge, I was swimming a 50-meter transect to survey fish underwater, and was stopped in my tracks when a school of several hundred pollack (Pollachius virens), each 1.5 to 3 feet long, started circling in the water column just above the canopy of the kelp forest and all around me. I sat there, simply revolving in the swaying fronds, allowing my body to be pushed gently back and forth with the current, watching this profusion of life unfold in front of me. For a minute I sat there, engrossed, completely oblivious to the time-sensitive task I needed to accomplish.

Wildlife filmmaker Luis Lamar calls these “moments;” those brief lapses where time stands still and the natural beauty of what’s in front of you mesmerizes and captivates you. All other sensory input gets blocked out, your mind goes still, and suddenly you realize you’ve been holding your breath. His work revolves around capturing those moments on film; I’m tasked with converting what I see into data we can use for our analyses and predictions. But every so often, we look up from our work underwater and are confronted with one of these scenes that pushes every other thought to the periphery.

This is the power of the marine life that abounds at Cashes Ledge. It can overwhelm even a scientist whose job it is to quantify and assess this unique underwater habitat. And the numbers speak for themselves: cod, pollack, and cunner abundances far surpassing anything seen elsewhere in the southern gulf of Maine, kelp forests 15 feet high, harboring an unparalleled richness of marine life. The importance of conservation here for both the local persistence of the marine community and for the replenishment of degraded habitats and fisheries throughout the region cannot be overstated.

But these moments, where the scientific pursuit of reducing the natural world to numbers gives way to pure fascination and enjoyment of wild beauty, remind us of a fundamental need for places like Cashes Ledge to be preserved. These are bastions of the healthy, productive, resilient ecosystems that once dominated the increasingly anthropogenic landscape around the world. It is our duty to conserve this legacy for future generations; to think not just of supplying the material demands of the present, but rather the persistence of a marine wilderness that invokes a wilder, pristine era. I work to ensure that we as a country and a community can take pride in the richness of life within our seas. I work for the protection of Cashes Ledge because marine wildlife such as this has the intrinsic right to exist, and we have the privilege to enjoy it.

Robbie Lamb is a PhD student and a diver with the Witman Lab at Brown University.




Videos from the dive:

A Movable Feast

When you think about grazing, you picture a big mammal with hooves eating a helpless plant – placidly chewing and digesting, right? Well, there’s another kind of grazing that is much more dynamic. Researchers at the University of Rhode Island have, for the first time known to science, discovered a plant that “runs away” to avoid being munched. The tiny Heterosigma akashiwo you see above on the right, not only makes tracks when predators like the Favella favella are after it (the big, mouthy guy on the left), but it will even avoid areas where there used to be predators, but no longer are. They are, in effect, fleeing the scent of danger.

Before you stand up and cheer for the little guy, you should know that this particular plant is one of the “red tide” phytoplankton that can cause major fish kills when it blooms. Dr. Susanne Menden-Deuer, an oceanography professor who studies the plankton at the University of Rhode Island, speculates that its ability to flee may be one of the mechanisms that allow Heterosigma to grow prolifically enough to kill fish. The plant, a type of algae, will take refuge in areas with lowered salinity – places where its predators cannot survive. As the algae move into these areas of refuge, they are free to reproduce with little to check their population explosion.

These harmful algal blooms can cause major devastation and millions of dollars in economic damage to fisheries – killing not only finfish like salmon and herring, but also harming oysters, copepods, and sea urchins.

Usually, though, Heterosigma are not harmful at all, blooming only occasionally in spring and fall. In fact, they provide many benefits to us – they are an important food source at the bottom of our productive ocean food chain. Not only that, but phytoplankton are responsible for giving us the oxygen in half the air we breathe.

Menden-Deuer plans to conduct further research to find out what the connections are between the fleeing behavior and harmful algal blooms, and if other plants might be up to this evasive behavior.

Photo credit: Elizabeth Harvey (URI-GSO). Digital enhancement by Cynthia
Beth Rubin (RISD).

Booming New England Seal Population Creates a Management Challenge

Note: This originally ran on Talking Fish on September 18th. Photograph by Rich MacDowell as entered in the New England Ocean Odyssey photo contest

Congress passed the Marine Mammal Protection Act (MMPA) in 1972, forty years ago. Intended to slow the precipitous decline of marine mammal populations due to human activities, the act prohibited the killing, harassment, or excessive disturbance of marine mammals in United States waters.

For seals in New England—mainly harbor seals and gray seals—the MMPA’s protections effected a massive boom in population. Previously, the animals were considered a nuisance to fishermen and tourists. Coastal states frequently offered bounties for the killing of seals. One study estimates that between 1888 and 1962, over 100,000 seals were killed in the bounty hunt in Maine and Massachusetts alone. This mass killing was enough to trigger significant regional declines in numbers. In 1973, a survey of Maine waters counted just 5,800 harbor seals; this was likely almost the entire population at that time.

The MMPA effectively stopped the bounty hunt in its tracks, and seal numbers have risen rapidly as a result. Each female harbor seal pups once a year and survival rates in New England without predators are high. In 2001, the estimated population of harbor seals in New England had recovered to 99,340 individuals; the observed number rose by 28.7% just between 1997 and 2001. Gray seals have seen a similar increase in numbers. On Muskeget Island, just 19 adult gray seals were observed in 1994; in 2011, a census estimated between 3500 and 3800 seals. The overall observed population of gray seals in Massachusetts has increased from 5,611 to 15,756 between 1999 and 2011.

This booming, unrestricted seal population has costs.  Seals eat commercially valuable fish like cod and herring, often taking the catch right out of fishermen’s nets. They can also cause costly damage to fishing gear. In 2011, the Canadian Department of Fisheries and Oceans determined that gray seals were hindering cod stock recovery, and the minister of fisheries proposed a cull of 140,000 seals.  It’s possible they may be having a similar effect in the Gulf of Maine.

To some degree, nature is responding to this abundant, high value food source. Rising seal numbers have been linked to the apparent increase in great white sharks around Cape Cod, particularly near the large seal colonies on Muskeget and Monomoy. Sightings of great whites have increased notably in the past decade, and this summer, a swimmer off Cape Cod was attacked by one for the first time since 1936. Killer whales and other high level predators also once controlled seals in this region and may return in the future in greater numbers.

In the mean time, seals are becoming a growing political problem. A local fisherman recently pointed out the seal problem to John Bullard, the new Regional Administrator for NOAA, at an open meeting in Scituate. Tensions are also rising between the seals and local residents. Last summer, five gray seals were found shot on Cape Cod beaches.

Coming to agreement about the appropriate management response to this situation is challenging. On one hand, the rising numbers can be viewed as a remarkable success of the MMPA and a return to natural conditions. One conservation response is to argue that the seal population will start to limit itself as numbers approach carrying capacity or as recovering shark numbers or other marine predators catch up with the new abundance of prey. On the other hand, some stakeholders have called for new, direct methods to limit seal numbers, including culling. The Seal Abatement Coalition has circulated a petition calling for “an amendment or exception to the Marine Mammal Protection Act which would permit the humane dispersion of [gray] seals.”

The original text of the MMPA allows the secretary of commerce to make some exceptions to the no-take rules, taking into account “the conservation, development, and utilization of fishery resources,” provided that “the taking of such marine mammal is in accord with sound principles of resource protection and conservation.” These have included the issuance of permits for marine mammals caught incidentally by commercial fishing operations. NOAA has also previously allowed the dispersion of sea lions in California that damage fishing gear and has permitted the killing of sea lions that were eating endangered salmon in the Pacific Northwest.

Nonetheless, it is unlikely that culling of New England’s seals will be allowed.  Beachgoers like spotting these charismatic animals and seal watching tours have become popular in some coastal communities. Harbor and gray seals are not widely regarded by the public as a nuisance, unlike California sea lions. In this context, it would take an “act of god” (as one state administrator put it)—or at the very least an act of Congress—to begin culling seals in New EnglandAs a Chatham fisherman told NPR last month, “There’s not a congressman in his right mind that’s going to be the first one out that says, ‘Let’s go harvest seals.’” Even with fisheries, the case for seal culling is modest. A recent study suggests that even if marine mammals were completely removed from the environment, potential catch from fisheries may not be dramatically improved.

There may be technologies that act or could act to reduce seal-fishing gear interactions non-lethally. “Pingers” like those used to deter porpoises from gill nets could be used to scare seals away from fishing gear. Still, this technology could be expensive to implement and may be ineffective on seals, which are highly intelligent animals and might even become attracted to the noise over time as they learn to associate it with readily available fish.

The solutions to New England’s exploding seal populations are not obvious, but the pressure for responses is growing and will continue to build. Seals are no longer just the stuff of children’s books and aquaria exhibits; they are back in force and growing rapidly. Natural seal mortality rates will undoubtedly increase over time, but as long as people and seals are both chasing after the same scarce fish resources, soon may not be soon enough for some.

Announcing our August Photo Contest Winner!

Congratulations to our “Hope” photographer! We love the golden light in this photo, the symmetry of the oars with the horizon and the untold story of this vessel and its flag. As a commenter posted on the Flickr™ page, “This is dreamlike. Looks so historical. It could be a hundred years ago or the future of our New England coasts if care is taken. It makes me want to know more about the story here! A real Ocean Odyssey I think!”

Check out our New England Ocean Odyssey Facebook page where we’ll be posting the honorable mentions over the next few days.

If you have pictures to share, there are still a few days left in our September contest!

Entering is easy! Explore New England’s oceans, take some photographs and then share them with our online community on Flickr™. All you need to do is add your photos to the New England Ocean Odyssey group and tag them “PhotoContestNEOO2012”. Find out more here.

Each month’s winner will receive a signed copy of Brian Skerry’s beautiful book, Ocean Soul. 

We look forward to seeing your photos!

Shark Bites

Dr. Dirk Schmidt/Marine Photobank


As a surfer and nature lover, I spend a lot of time thinking about sharks. I also read about them, talk about them, and blog about them. As a result, people send me lots of shark “bites” – news items, factoids, movies, etc. So, to wrap up a fantastic week of sharks, I thought it would be fun to geek out on some of my favorite shark bites from the year. Be warned – if you are squeamish you may want to skip the first two bites.


Shark-Eating Sharks

Wobbegongs may have the best name of any shark. They are also pretty tough. They hide on the bottom of the Pacific and Indian Oceans and ambush their prey. Check out these amazing pictures of a wobbegong snacking on its neighbors – swallowing them whole. That’s quite a predator! I think I’d keep my feet off the bottom of that reef.


Mysterious Disappearing Aquarium Animals

Should you keep sharks and octopi in an aquarium together? You’ve probably already guessed the answer.




Most Misunderstood Shark of the Year Award Goes To:

The large but harmless basking sharks of Cape Cod made news this summer as they showed up in all kinds of interesting places. First, we saw one nearly stranded in the Pocasset River, scaring children. Then we had the infamous kayak-following shark of Nauset Beach. While these sharks pose no threat to people, they are quite big and they gave us some thrills this summer. As my surfing buddy Jonathan Lewis put it: “We’ve had the Summer of Love, the Summer of ’69, and now we’re having the Summer of the Basking Shark (aka The Story of the Dude Who Just Wanted to Vacation on Cape Cod … But Everywhere He Went People Kept Freaking Out Because, You Know, He Was Actually a Pretty Big Shark).”



Great whites have certainly been in the news this summer. WBUR summed up the situation well, with this excellent blog about the complicated connections among white sharks, seals, and tourists on Cape Cod.  In short, researchers are learning about the feeding and roaming habits of our top predators so that we can make sure to clear out of the water when they get near our favorite swimming beaches. Scientists are tagging white sharks with “pingers” that can be picked up by underwater acoustic receivers, so we can keep track of their movements. The problem, though, is that we don’t have enough receivers in the water to cover all our beaches. Or, as WBUR colorfully put it “We’re gonna need a bigger acoustic array.”



The Shark You’ve Probably Never Heard of but Really Should Know About

And, finally, one of my favorite boneless fish: the very large (up to 21 feet), and very mysterious Greenland shark. These sharks live at the frigid bottom of the Arctic and North Atlantic Oceans, and are quite lethargic when observed – so lethargic that they are in a family called “sleeper sharks.” They have one of the most pathetic sounding scientific names I’ve ever heard – Somnius microcephalus. Now, my command of Latin is minimal, but I think that means “sleepy little-brain” or something similar. Ouch.

In contradiction to their unfortunate “branding,” researchers have found all kinds of fast moving animals in Greenland sharks’ stomachs, like salmon, rays, and seals – with evidence indicating these animals were caught alive.  Even more mind-boggling, they also eat reindeer – earning them the moniker “Canada’s crocodile”.

This prodigious predation is all the more impressive given that many, if not most, of the Greenland sharks have parasitic copepods on their eyeballs, rendering them blind. That is one tough shark, to make a living under those conditions.

Check out this video by Jonathon Bird of his Greenland shark encounter in the St. Lawrence River, where these Arctic sharks visit in the summer months. (If you want to get straight to the action, skip to the 6 minute mark).



One last fun tidbit about Greenland and other sleeper sharks – they have been observed swimming in fresh water, and there is some speculation that they may be the real Loch Ness monster.


There are so many great shark stories in the world, and these are just a few of my favorites. What are yours?


Basking Sharks – A Big Fish Story

We’ve shown some amazing pictures of predatory sharks this week, but the biggest shark in New England’s waters is a gentle giant, feeding on tiny crab-like creatures called copepods. The basking shark, so named because it is often observed feeding near the surface,“basking” in the sun, is not only big, but is still a huge scientific mystery.

I recently caught up with one of our New England ocean celebrities, Greg Skomal, noted shark expert and Senior Fisheries Biologist with the State of Massachusetts, who filled me in on the state of basking shark knowledge.

Robin: How often do you encounter basking sharks in your work?

Greg: If we’re actively working on them, we find them frequently.

Robin: How do you know where to find them?

Greg: We use a spotter plane. Also, fishermen and whale watchers will help us figure out where the sharks are.

Robin: Have you spent much time in the water with basking sharks?

Greg: I have – some of that work has been to tag them underwater using a pole spear, but I’ve also filmed and photographed them.

Robin: How do they behave around humans?

Greg: They are generally shy, but I see two kinds of behavior. It’s either one or two sharks moving in straight line, searching or going someplace – cruising. If you want to dive with them you get the boat to put you right in their path, but they tend to get out of your way pretty quickly. The other kind is group behavior – small to large aggregations. You just jump into the water with them. Individuals will start to dive, but the group as a whole continues to feed.

The best way to dive on basking sharks is to find a group of them.

Robin: Do you ever feel any threat from them?

Greg: No, but I will say it’s an overwhelming experience because of their sheer size, so there’s some anxiety about just being in the water with such a big animal.

Robin: How big do they get?

Greg: They’ll get in excess of 30 feet long. I’ve seen two that big – beached animals. Much of what we know about basking sharks comes from beached animals.

Robin: What can you say about the shark in this photograph?

Greg: Here’s the fascinating thing about this picture – the snout on this animal is more pointed than on the average basking shark, which tells me it’s a juvenile and probably not very big. Basking sharks are born with a pointed snout, and they lose that over time and it becomes more rounded.

Robin: Why does that happen?

Greg: We don’t know a lot about the biology of these critters – about the changing of morphology and shedding of the gill rakers. For the second largest fish on earth we know amazingly little about its natural history.

Robin: What do you mean by shedding of gill rakers?

Greg: Gill rakers are used to sift plankton – like baleen in a whale. Basking sharks shed their gill rakers over the winter. Because of this, and their disappearance in the winter, scientists in the 1940s and 50s hypothesized that the sharks went to the bottom of ocean to hibernate.

This theory was published in a scientific journal, and was accepted for many years, until we started tracking them recently. It wasn’t until the turn of century that we started tagging these sharks and found out where they do go.

Previous scientists were correct that the basking sharks in the eastern Atlantic go deep and move off the shallow shelves, but they don’t go far. They just move to deep water where they don’t interact with humans and so were not encountered. This was discovered by David Sims and his crew in tagging studies. He was the first to demonstrate that they don’t hibernate.

So, we did same studies here on the western side of the Atlantic, but found that our basking sharks do something very different. They go to deep water, but they also go really far away. We published a paper in 2009 showing that they move to tropical areas: the Bahamas, the Caribbean, even south of the equator to Brazil. They make very broad migratory movements – some of the greatest ever described by science for a fish. But they still stay at great depths (3,000 feet or more) when they move.

Robin: Why do they go so deep?

Greg: You just asked the best question there is. We don’t know why. We hypothesize that movements of fish are driven by food and reproduction. We know they could go somewhere besides the tropics to get all food they need, so they might be traveling there to reproduce. They might come to the Gulf of Maine to mate, and then pregnant females might move south to gestate.

Robin: So they might be like right whales?

Greg: They do show up where right whales go, but they also go much further south. They go from the Gulf of Maine to south of equator. It must be energetically beneficial to do this, otherwise, why do it? But we can’t prove it yet.

Robin: Have you noticed a change in their numbers or distribution over the years?

Greg: It’s tough to know. The general thinking is populations are down in the Pacific, and perhaps the eastern Atlantic. But we don’t know about the western Atlantic. We don’t have populations trends here because we don’t have the data.

Robin: What are the greatest threats to basking sharks?

Greg: Bycatch, right now. They are sometimes taken by fixed gear as bycatch, in lobster, conch, or any other kinds of traps. Sharks inadvertently get wrapped in lines. Sometimes they get caught in bottom trawls and gill nets.

We don’t know what the implications of climate change will be. Maybe there will be a shift to the north, or a shift vertically in the water column. If you can determine what’s going to happen with the copepods they eat, you’ll have better sense of what might happen to basking sharks.

It’s an amazing species – phenomenal to be in the water with. I’ve put a lot of time into studying them and hope to continue to do so.

Healthy Sharks – Healthy Oceans

I love diving with makos, but they have a very different behavior than other sharks. They come in appearing to be more agitated. They’re much more hyper and jacked up.” – Brian Skerry

Mako sharks are built to move. They are very acrobatic – sometimes leaping high into the air – and are also extremely fast. Some scientists think they are the fastest fish, possibly going over 50 mph at times. (Fun fact – makos are one of the only “warm-blooded” fish, which helps explain why they can move so fast, even in colder water.) Makos need wide open spaces and healthy places to eat and reproduce. The health of our oceans depends on healthy top predator populations, and healthy top predators depend on healthy oceans.

Our nation has taken a major step forward in protecting the health of our oceans with the National Ocean Policy – which calls better management through agency coordination, science-based decisions and robust public and stakeholder involvement.  One important priority of the National Ocean Policy is to protect ocean habitat and wildlife while supporting sustainable new and traditional uses of our ocean.

Regional ocean planning and ecosystem-based management are two other key components of the National Ocean Policy that can go a long way in protecting our top predators. Regional ocean planning is a process that brings together all our ocean stakeholders – from fishermen to whale watchers, from beachgoers to renewable energy developers – to help us figure out how to share the ocean sustainably. This process helps all New Englanders use and enjoy our ocean and coasts while making sure we protect ocean wildlife and habitats and maintain the benefits these resources provide for us all.

For an example of how regional ocean planning can protect marine wildlife, check out this blog about endangered North Atlantic right whales and shipping lanes.

Collecting and sharing good data, and using it to help make ocean management decisions, are some of the keys to succesful regional ocean planning. If you are wondering how this might apply to mako sharks, check out this app from NOAA that allows fishermen to share information about caught and released makos – to literally put that shark on the map. NOAA says “Overfishing is occurring on the North Atlantic shortfin mako shark population. By releasing shortfin mako sharks that are unintentionally caught or caught for sport, fishermen can lead the way for conserving this shark species.” Now that sounds like some good planning.

Are you ready for some sharks?

We are excited to bring you some amazing new pictures from Brian Skerry this week. Brian has been diving all summer off the coast of Massachusetts and Rhode Island so we can show you some of our biggest fish. This week we will not only be showing you these pictures but also bringing you an exclusive interview with Brian about his shark diving experiences, and his thoughts on shark conservation. There will be tons of shark stories, shark pictures, and shark love this week. So come back tomorrow and meet some of your saltwater neighbors!