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The Shark Tracker – an Interview with Greg Skomal

Categories: Events/Calendar

Dr. Greg Skomal is senior fisheries expert with Massachusetts Marine Fisheries, and the State’s leading shark expert. He spoke with us last year about his basking shark research. He has recently been part of a research team that is investigating the use of robot shark tracking technology, as featured on Discovery Channel’s Shark Week, which he talks about below. 

Keren: Thanks for taking the time to talk to us about the exciting new shark tracker technology where robots (autonomous underwater vehicles- AUVs) follow sharks in our waters! Can you tell me how this project began?

Greg: Conceptually this goes back many years – to around 2008. We were starting to track basking sharks with various kinds of technology and learned that these sharks spend quite a bit of time diving. We were curious about what they do when they dive and thought it would be interesting to have a robot follow them and sample the water column to see what they’re eating. We worked with a plankton biologist at Woods Hole Oceanographic Institute (WHOI), and WHOI gave us the initial funding in 2008. That was the first time we were able to develop an AUV that could track marine animal.

Then, we were making a show with Discovery on white sharks in 2010 and one of the producers of the show found out what we were doing with AUVs at WHOI and he suggested that Discovery might fund that research! So in 2011 and 2012 we began fieldwork with the WHOI oceanographic systems engineering department developing and implementing the AUVs.

What’s happening currently is an engineering feat. I’m a marine biologist so I can provide a sense of how a shark might behave, and based on that engineers are able to program the software and the machinery.

Keren: Can you explain more about what the AUVs actually do?

Greg: It’s essentially an unmanned mission under water; you can program the AUV to do many different things, like map the ocean floor or do water sampling. The robots can do something as simple as ‘mow the lawn’ (go back and forth on the ocean floor taking data) or something as complex as tracking a shark.

In November 2011 we began field trials, simulating tracking something with an AUV. The first step was to have the robot try to follow boat, then a person. I dove in the water and swam around, and the AUV followed me. In 2012 the AUV did its first marine mammal track, following a basking shark.

Keren: What specific kind of information does the AUV collect?

Greg: With these kinds of AUVS you can measure pretty much anything- depth, current profiling, basic oceanographic data like temperature, dissolved oxygen, salinity. There are various modules you can clip onto the AUV, so if you want additional measurements, like amount of chlorophyll and plankton abundance, you can get that information too.

Keren: Can you explain more about how the technology works?

Greg: Sure – you can’t train a robot to recognize a fish, instead, you put a transponder on the fish. Generally, there is a communication system, which transmits a high frequency ping from the fish to the robot. In this new technology we’re using with the sharks, it’s a bit more complex- there’s actually two-way communication where the tracker asks questions that can be answered. The tracker can learn information about depth, range, and bearing from the transponder. The tracker can then navigate relative to where animal is, and follow the shark in a more precise manner. We have to catch the shark to put the transponder on it and the technology has a release mechanism so it will detach after a certain amount of time.

Keren: Similar work has been going on the West Coast, what are the differences?

Greg: The method by which the animal is being tracked is different. On the West Coast researchers attach a high frequency tag to the shark and the AUV detects the sound and positions itself based on directionality and intensity of sound source. The AUV can track for several hours doing that. This technology involves a lot of searching and listening- the communication is more passive.

The technology we have developed involves a more robust navigational system where the two devices can interact, allowing more precise tracking and positioning. The transponder can send information through underwater modem technology to the AUV, and the AUV can ‘ask questions’ back to the transponder. For instance, our transponder can detect depth and send this information back to the robot. Our system also has more video capability. However, it’s a bigger transponder. The technology on the West Coast is smaller, and therefore can attach to smaller sharks.

I fully support the development of multiple technologies because I think what will eventually emerge is the best of both worlds.

Keren: What are the main difficulties using AUVs?

Greg: You have to tag the shark, and that’s always a challenge- we’ve had great success in doing it but it can be hard. Any time you put electronics in the ocean there are many factors to consider. The engineers at WHOI do a really great job with ocean technologies.

Also, robots don’t always know what sharks are going to do next; we are always trying to figure out ways to predict the behavior of the shark. If we can predict what the shark will do we can arm the AUV with the best information for making decisions.

Keren: What are you most interested to learn?

I’m interested in understanding the fine scale behavioral data we’re getting. We’re learning about the movement of the sharks, things we had no idea about before. For instance, we’ve learned they have no problem swimming against the current at sustainable speeds of 5 or 6 knots.

We can also learn about their movements as they relate to the environment in which they’re swimming, like behavioral changes with regards to tide and time of day, do they move off shore, and if so when, in general, what are their daily behavioral patterns?

It’s a lot of cool novel data we’re gaining from these AUVS, almost everything we’re learning is new- it’s really exciting!

Keren is a rising senior at Cornell University studying Biology and Society, with minors in Marine Biology and Science of Earth Systems. She has loved the ocean since she was old enough to walk along the sea shore. Keren recently spent time researching water quality on the Kona Coast of Hawai’i Island with The Nature Conservancy. She has also researched the Maine intertidal ecosystem as it reacts to climate change at Shoals Marine Laboratory. Keren is a native of Southern Maine, where she enjoys taking her dog for walks and exploring the rocky coast. She was a summer intern with the Communications Department at CLF.

Dogfish out of its normal habitat. Photo by Executioner via Wikimedia Commons.
Dogfish out of its normal habitat. Photo by Executioner via Wikimedia Commons.
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Man, Eating Shark

I tried to eat a shark last week and couldn’t find one. Recent estimates suggest that as many as 100 million sharks are killed by man each year whereas fewer than 20 people are killed by sharks. That means that I had about a 5,000,000:1 chance of being the eater, not the eaten, but I still struck out.

My plan was to kick off Shark Week by feasting on Squalus acanthias, aka Spiny Dogfish, and reporting my impressions. A local chef achieved minor celebrity status last year by feeding one of the omnivorous TV cooking show hosts the “best dogfish” he’d ever eaten. While this particular diner’s habits must be approached with caution– he pretends to like beetles and calf brains, for example–I thought this would be a fish I could try in good conscience.

Spiny dogfish are one of the few fish populations in good biological condition that New England fishermen can still catch, having recovered from a crash back in the early 1990’s. Once a fish despised because of the havoc it caused with fishing gear and its voracious predation on more valuable commercial fish, many fishermen who can no longer find cod or other prime species are turning to dogfish out of financial desperation. Eating shark for one meal seemed the least I could do to stimulate market demand.

Spiny dogfish has cycled through fish markets several times in the past. Stuck with a name that reminds many consumers uncomfortably of their cherished canine at home, dogfish mechandisers have resorted to various aliases over time, from “rock salmon” to “mud shark” to “Japanese halibut” (seriously!). The most recent New England marketing label is “Cape shark,” a reference to the swarming abundance of these sharks off Cape Cod.

While most sharks are decidedly more valuable left in the oceans, I was willing to make an exception for dogfish, at least in the short run. They, together with their cousins, the skates, have moved into the vacuum created by overfishing of cod and a number of types of flounder. More than “moved in” to that niche, they seem to have almost overrun it. Without some focused removals of dogfish and skates, some scientists think it might be difficult, if not impossible, for a number of groundfish species to recover.

In any event, dogfish are abundant, the dogfish fishery in New England has been blessed by an eco-labeler as sustainably caught, and all that is missing are markets. Most dogfish are destined to the whims of the European fish markets to become the “fish” of “fish n’ chips”, but that market is unreliable and prices to the fishermen barely cover costs.

In fact, fishermen in New England recently asked to have the U.S.D.A. purchase dogfish for the nation’s school, prison, and institutional menus: a surefire way to build demand and markets. But I was interested in eating it in a restaurant, not a school cafeteria. Rather than low grade the markets for this fish, if it was indeed tasty, why shouldn’t it occupy a place of honor for New England diners?

Alas, there was no finding a single place that served dogfish. I dropped in on my local chef and he was serving a fabulous skate wing recipe but no dogfish. He couldn’t get any for me, but whenever he did get it, he said, it always sold out each night and early. I called one of the New England Fishery Management Council members, who works for the redoubtable Foley’s Fish in New Bedford and she told me, “No, we don’t buy it or sell it.” The Cape Cod fishermen told me that they were told not to land any dogfish.

So despite the 5,000,000:1 odds of me being the one who ate shark, there was no shark on the table for me for Shark Week.

Maybe it is just as well. There are all sorts of challenges to having a truly sustainable dogfish fishery, including the fact that New England fishermen are not known for producing sustainable fisheries. Moreover, dogfish reproduce very slowly, and the targeted animals for fishermen in the past have been the females, which are larger. (Not a very good long-term strategy, catching just the females.) In addition to management challenges, the fish have to be handled well from the moment they are caught or they taste bad – like uric acid (urine to the lay people). One bad plate served to the public would sour people on dogfish for a long time to come.

So dogfish is safe from me, at least for the moment. I have a standing order from the street for the chef to call me as soon as he gets a supply and I am looking forward to it. If there is any left on my plate, which is unlikely, I can’t wait to ask for my “doggie bag.”

Bigeye thresher shark caught in a gillnet. Copyright Brian Skerry.
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Sharks – A New Ethic

Categories: Events/Calendar

Brian Skerry wrote the following Op-Ed for the New England Ocean Odyssey last summer. It first appeared in the Boston Globe on August 8th, 2012. Please help us share his conservation message.

Shark. The word alone evokes an almost visceral response of fear in humans. Peter Benchley once commented that when he wrote his novel Jaws, he unknowingly tapped into some primal fear that exists within people—a fear of being eaten by another animal. Beachgoers on Cape Cod may have been channeling Benchley in recent weeks, as great white sharks have once again been sighted near Chatham, dredging up that thrilling mix of fear and fascination that sharks seem to evoke. While no one wants to see a shark swimming next to their boogie board, the reality is that the likelihood of being bitten by a shark is infinitesimal. And, as Benchley observed in the years following, sharks have far more to fear from us than we do from them.

I swam with my first shark in the 1980’s. I was twenty miles off the coast of Rhode Island, working with a group of marine scientists. Late in the day, a five-foot long blue shark swam into our chum slick and for the next hour I marveled at the animal’s stunning indigo color and the elegant way she moved effortlessly through the sea. I was hooked, addicted to sharks.

Since then, I have spent a great deal of time in the company of sharks in waters around the globe and, as recently as last week, right here in New England, where I photographed blue sharks and basking sharks. For a photographer, sharks are a stirring subject, possessing a perfect blend of grace and power. They have been sculpted by evolution and are ideally suited for whichever ecosystem they inhabit, from coral reefs to the open ocean. During decades of exploring underwater and spending time with sharks, I have learned to appreciate how critical they are to the health of the oceans. I have also seen that they are being decimated at alarming rates and desperately need our help.

On Cape Cod, great white shark stocks have been growing, or at least becoming more concentrated, because of the multiplying numbers of seals around Monomoy Island. We are fortunate to have such abundance of these sharks in our own waters. Around the globe, we are killing in excess of 100 million sharks each year. As apex predators — that is, predators that lack natural predators of their own — sharks play a vital role in the health of ocean ecosystems. Yet, in the last sixty years, we have lost an estimated 90% of shark populations to our own predatory behaviors like overfishing and “finning” sharks for shark fin soup. Remove the predators and the whole ecosystem begins to crash like a house of cards. As the sharks disappear, the predator-prey balance dramatically shifts, and the health of our oceans declines. Given that the majority of the oxygen we breathe comes from the ocean, not to mention much of the world’s protein, it is not an exaggeration to say that when our oceans’ health declines, our very survival is at risk.

I believe it is time for a new ethic, a new view of the sea and its inhabitants. Like lions and tigers, sharks are predators and must be respected. As human populations increase and more people take to the sea for recreation, we must be vigilant about how our own activities interact with wild animals. We should not view sharks as villains or perpetuate the myth of them as monsters. And although the majority of sharks killed are caught on longlines and in gillnets, I believe the time has passed for individuals posing like dragon-slayers next to a dead shark they have caught. I have the greatest respect for the skill of fishers, but killing sharks should not be celebrated, given how important they are to us.

So with sharks making headlines once again, we should pause to consider the value of these misunderstood animals. Lets take our curiosity and intrigue about sharks to the next level and seek to learn even more about them. I am confident that awareness will be followed by concern, followed by conservation.

Image credit: Museum of Natural History, UK http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/osedax-mucofloris/
Image credit: Museum of Natural History, UK http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/osedax-mucofloris/
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Bone-Eating Snot Flower Worms – The Name Says it All

Categories: Creature Features

What’s in a name? In this case – a lot. Osedax mucofloris, which roughly translates to “bone-eating snot flower worm,” is a spot on description of this intriguing little animal. This is a worm that eats whale bones (or steak bones Donald Trump threw off his yacht, or whatever old bones they find), and has a set of frilly gill-like things that float around outside whatever carcass they are consuming, looking like decorative tassels or, well, snot. There are several other kinds of Osedax, besides the snot flower variety. But they all eat bones.

And they have no mouth, gut, or anus.  So, how do they eat? A bunch of bacteria hang out on the worms’ “roots” – appendages they use to burrow into the bones. The bacteria break down the lipids inside the bone into easily absorbed nutrients, so the worm can enjoy pre-digested rotted whale.

The bone-eating worms are exclusively female, the males having been relegated to microscopic hangers on. The males never develop once they hatch, they keep their egg yolk with them their whole lives and just hang out inside the fully developed females and release sperm now and then. Why? Monterey Bay Aquarium Senior Scientist Robert C. Vrijenhoek speculated, “These worms appear to be the ecological equivalent of dandelions—a weedy species that grows rapidly, makes lots of eggs, and disperses far and wide.” When you are hopping on unpredictable ocean currents from dead whale to dead whale, it probably makes sense to cast a wide reproductive net – just like a weed.

Look at this great video about them. This story truly needs no embellishment.

Bone eating snot flower worms are only a couple of inches long, but have an outsized role in the ocean – decomposing dead animals and recycling nutrients back into the ecosystem. There is so much we don’t yet know about these interesting animals, including where they live, since they were only recently discovered. According to Dr. Vrijenhoek, it’s reasonable to think they live here in New England:

“Various species of Osedax boneworms are known from Oregon to the Southern California margin, from Japan and Papua New Guinea, and they were recently found off Antarctica. To my knowledge, Osedax have not been found off New England, but I don’t know of anyone who is looking for whale carcasses or sinking bones there. One of the Pacific species, O. rubiplumus, occurs off California and Japan; therefore, I would not be surprises if the species described from Sweden, O. mucofloris, also occurs off New England.”

If they do live in New England, then they are wicked cool bone-eating snot flower worms.

Humpback whale and Smokestacks by Devra-minicooper93402
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Threats to Marine Life from Ocean Acidification

Categories: Guest Posters

As climate change moves to the forefront of our agenda, we are getting more concerned about what effect the increasing levels of carbon in the atmosphere are having on the planet’s biggest carbon sink; the ocean.

Atmospheric carbon dioxide is rising to levels unprecedented in modern geological history, and as a result our ocean is experiencing changes to its chemistry that may significantly alter habitats and affect marine organisms. Collectively, these changes are referred to as ocean acidification, or a lowering of global ocean water pH due to the absorption of excess carbon dioxide. Scientists have only begun to investigate this process, but it is likely to have a profound impact on New England waters and the species that coastal communities rely upon.

Ocean acidification is a relatively new term for most of us, as a large percentage of the research on this subject has been conducted within the past decade. Scientists have identified a number of changes that occur when CO₂ is dissolved in water. The primary outcomes include an increase in the concentration of hydrogen ions, lowering pH and ‘acidifying’ ocean waters, and the consumption of carbonate, an important component for shell-building organisms. These changes could place stress on marine-dwellers, particularly the critters that require carbonate, like oysters, mussels, clams, and corals, to build their shells or skeletons.

But the ocean is huge! How do we know that these changes are occurring on a scale large enough to affect global ocean chemistry? Scientists have information about past atmospheric and oceanic conditions from clues in the geological record. They can compare these records to projections about how much carbon is likely to be in our atmosphere- and subsequently our oceans- in 20, 50 or even 100 years. The ocean’s pH has dropped from 8.2 to 8.1 since the Industrial era- that’s a 30% increase in acidity- and is projected to fall another 0.3-0.5 units by 2100. Researchers claim that this drop in pH is unlike anything the ocean has undergone in the last 300 million years!

One recent study has shown that the waters of the Gulf of Maine are particularly susceptible to acidification due to already low pH and carbonate levels relative to other regions along the Atlantic coast. This means that we New Englanders could end up with a front row seat to the impacts of ocean acidification!

What does this mean for ocean-dwelling animals? It’s impossible to know how every species will react to changes in ocean chemistry. Some studies have shown that rapid changes in water chemistry can place heightened stress on shellfish, affecting growth, development rates, and even survival. Another study has shown that acidified waters impair organ development in our already-depleted Atlantic cod. “Adapt or die!” –says Darwin, but these human-made changes may be happening too fast for nature to keep up.

The ocean is so important to us, and it’s difficult to imagine how these changes might affect our daily lives. Many fish and shellfish species are critical to our economy, and are relied upon as integral parts of people’s livelihoods. Seafood lovers can’t deny the importance of the ocean as a food source. Beyond our stomachs, the ocean also appeals to our emotions. CLF’s Keren Bitan recently discussed how learning about sea critters can foster a strong personal connection to the ocean and its ecosystems. And anyone who’s explored the tiny world of a tidal pool, or taken a morning walk on a sandy beach, can appreciate the beauty and complexity of the ocean and its habitats. These connections are often what compel us to realize just how important it is that we continue to protect ocean habitat and do what we can to prevent climate change from taking its toll on the world’s oceans.

We have explored less than 5% of our ocean, and yet we may be changing it in ways we are only beginning to understand. We will continue to work to protect the ocean’s resources, animals and habitats, even as the uncertain effects of climate change become apparent.

Ellie Milano is a current Masters student at Tufts University studying Conservation Medicine, an innovative program that seeks solutions to global environmental and health issues. Her thesis work focuses on public opinion of global climate change, and understanding how extreme weather events affect attitudes toward climate change. She is a recent graduate of Hobart and William Smith Colleges in Geneva, NY, where she double majored in Biology and Environmental Studies. During college, she spent two summers at Cornell University studying aquatic ecology. She grew up in the Berkshires of Massachusetts, and her interests include horseback riding, recreational hiking and rock climbing.