Cape fur seal white shark research EDNA Science Dyer Island Conservation Trust

Infographic: How seals use subsurface structures to sneak by white sharks

Written by Michelle Jewell.  Follow her on twitter: @ExpatScientist

If you have ever avoided parking on a risky-looking street or taken a different route between classes to avoid a bully, your behaviour has been altered due to the perceived presence of ‘predators’.  In the wild, prey animals also change their behaviour when they think predators are around, and these altered anti-predator behaviours can often influence other species, and then influence more species, and eventually change the entire ecosystem.  This is an example of indirect effects predators have on ecosystems.

My research has focused on these principles of predator/prey interaction in the ocean, and a great place to study oceanic predators and their prey are Cape fur seal colonies in South Africa.  Every summer in the southern hemisphere (November), Cape fur seals give birth to thousands of pups.  For example, the seal colony Geyser Rock has a population of about 60,000 Cape fur seals and every year they give birth to 10,000 seal pups!  By winter (April – September) these 6 month old ‘young-of-the-year’ seals begin to venture off the colonies and swim offshore with the adults to the fishing grounds.  These young-of-the-years are typically slow, plump from months of a mostly fat milk diet, and – most importantly – naïve.  White sharks take advantage of this naivety and aggregate closely around seal colonies every winter to catch leaving/returning seals.  Young-of-the-year pups are forced to learn how to avoid sharks quickly or suffer some rather permanent consequences!  This means that during a full year, every seal colony goes through a period of high white shark presence (winter) and very low to no white shark presence (summer).  Therefore, we can see how seals act ‘normally’ during the summer when there are no/very few sharks and how they change their behaviour in the winter to avoid white sharks.

Dyer Island Geyser Rock Shark Alley South Africa Seal Island False Bay

A) The Western Cape of South Africa with B) Seal Island, False Bay and C) Dyer Island & Geyser Rock.

Also, there are many different kinds of seal colony islands along the coast, which lets us ask more questions about how seals use their environment to avoid sharks.  I conducted my study at the Dyer Island/Geyser Rock system, which is home to ‘Shark Alley’ as well as many shallow reefs, kelp forests, and shipwrecks.  About 100km to the east is another seal colony called Seal Island, which is a world-famous spot to see white sharks predate on seals, but this island system lacks the abundant nearby structures/reefs/kelp forests that are present at Geyser Rock.  By looking at these two different kinds of islands, we can also examine how structures – or ‘refugia’ – may alter how seals avoid white sharks at Geyser Rock from how seals avoid white sharks at Seal Island.

And here’s what we found…

Agents of seal cape fur white shark research dyer EDNA Science

Do all of these structures and anti-predatory tactics of Cape fur seals change white shark movements around Geyser Rock?  Most definitely!  Check out that study (and infographic!) here.

This project was funded by the Dyer Island Conservation Trust and supported by Marine Dynamics shark tours, Volkswagen South Africa, and OCEARCH.  The infographic was designed by EDNA Science.  You can read the detailed scientific publication on Behavioral Ecology & Sociobiology by clicking here.

Have a question?  Leave it in the comments and I will answer!

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Your Starting Point Doesn’t Matter

Written by Dr. Michelle Heupel

When I was 14 I decided that I would be a marine biologist, not just any marine biologist, a shark biologist. This was before I saw the ocean for the first time. A whole bunch of people just said “what?” No, I’m not confused, this is how it happened. And yes, almost everyone said I was crazy.

My point in this blog is to say that it doesn’t matter where you come from, you can be who or what you want no matter what your starting point. All you have to do is apply yourself and go for it. So where do I come from – where did I start? I grew up in South Dakota until I was 14 when my family moved to Colorado. Very solidly in “the middle” of the US – no growing up on beaches for me. I don’t know where the decision came from to go study sharks, it was just there.

So how did I manage getting from the middle of the US to becoming a shark researcher? Two main ingredients: support from my family and hard work. My parents are amazing. While everyone else was telling me I was crazy they consistently said – don’t listen to anyone else, if this is what you want to do then put your head down and go do it. One of the most vivid memories I have from high school has to do with this support. I went to the guidance counsellor to ask for some material about colleges and told him I wanted to study marine biology. He told me I would never make it, would never get a job and that I should change my senior year classes so I could become a bookkeeper or accountant. I went home in tears. My Mom happened to be home when I walked in that day (she was usually at work) and she asked me what happened. I told her the story and she asked who had told me this. She then phoned the school, asked for the counsellor and proceeded to tell him off. I clearly remember her saying “Don’t you dare tell my kid she can’t do something she wants to do!” She then hung up the phone and said to me, “don’t ever listen to people like that, if you want to do it, go do it”. Several times this journey has gotten difficult and I have considered quitting. Each of these times my family has been there to support me and encourage me to keep chasing my dream. To say my family have been crucial to my success would be a huge understatement.

michelle kid

A photo of me from South Dakota holding a sunfish I caught in one of the local lakes.

So, if you don’t have someone in your life who will tell you the things my family has, find someone who will, or let me be that person. Do not give up on yourself, do not give up on your dreams and goals. Work hard and give it your best. If it doesn’t work out at least you know that you gave it every chance.

So here I am, a shark biologist with almost 20 years of experience in the field and sometimes I wonder – who was the crazy person all those years ago? I don’t think it was me.

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I’ve moved on to fishing for bigger things – fishing for blacktip sharks in the Florida Keys

A Typical Day on this Research Cruise

Written by Helena Aryafar

*Helena tags and collects biological samples from juvenile and adult blue sharks on federal research cruises

5:30 a.m. (~sunrise)-6:30 a.m.  Set the longline gear (Set 1) 
Setting gear requires baiting the hooks (~200 per set), putting lightsticks above each hook (these attract fish to the bait in the deep dark waters), throwing the line out into the water, and attaching and releasing buoys to separate baskets of hooks.  This process usually takes around an hour to an hour and a half.  This will be set #1 and will soak (soak = stay in the water) for 10 hours before we haul it back on deck.  Immediately after set #1, we will motor to another area to do 1-2 shorter sets that will only soak for ~2 hours each before we haul the gear back. 
Buoys and radio beepers (used to find the longline gear for haulback)

Buoys and radio beepers (used to find the longline gear for haulback)


8:30 a.m.-9:30 a.m. Set the longline gear (Set 2)

9:30 a.m.-10:30 a.m Prepare tagging and sampling gear for haulback; deploy CTD (Conductivity, Temperature, and Depth device)–CTD provides us with information about the habitat in which we are fishing
The set-up for haulback and sampling

The set-up for haulback and sampling

Electronic tags

Electronic tags


10:30 a.m.-12:00 p.m Haulback of Set 2

When we are ready to haul the gear back on deck, the main line will be pulled back onto the spool and each hook is removed and put back into a large bin to be used for setting the gear next time.  As the animals come up, we assess the condition of the fish, pull them onto a cradle that gets hoisted onto the deck with a hydraulic winch, and begin working up the animal.  Sharks will immediately get a ventilator (hose with specially fitted mouth piece) to run water over their gills, a wet chamois or towel is used to cover their eyes (which keeps them calm), and the hook is removed.  We take length measurements and determine sex of the animal (claspers vs. no claspers).  A small corner of the dorsal fin is clipped and saved in alcohol as a DNA sample, and depending on the size of the shark and which project we want to use that sample for, either a conventional tag (a thin piece of plastic that contains a unique ID number and contact information for fishermen to use in the event of recapture of the animal) or an electronic tag (that provides data on location and movement patterns) is inserted near the dorsal fin.  We will also be taking blood samples to measure lactate levels, which can give us information on the stress level (condition) of the fish. Some of the sharks will also receive a secondary tag (with reward information for recapture) and antibiotics that function as a marker of when they were captured and can be used to determine age and associated growth of the shark if it is recaptured in the future and the vertebrae are returned to our lab.  Once the sharks have been tagged and/or sampled, we return them to the water and assess condition once again.  Sharks that are not alive upon haulback of the longline will be processed for biological samples that include: stomach (can be used to determine what the shark has been eating and which habitats it exploits), liver/muscle/heart tissues (used for stable isotope analysis which can tell us about its movements and where it spends a lot of its time), and gonads (used to determine maturity and provide information on reproduction).      

Tagging

Tagging

Ventilated male shark with a roto tag and conventional tag just before release

Ventilated male shark with a roto tag and conventional tag just before release

1:00 p.m.- 2:00 p.m. Set the longline gear (Set 3)
3:00 p.m.- 4:30 p.m. Haulback of Set 3
5:30 p.m.-7:00 p.m. Haulback of Set 1

Repeat for 10 days and pepper in some tagging of opah and swordfish. Rough seas, long days, hard work, and lots of fun!

My bunk for 10 days...pretty cozy

My bunk for 10 days…pretty cozy

Science Saving Sharks

Written by Dr. Michelle Heupel

How are scientists helping to save sharks?

There is a lot of information on the internet about sharks and how to save them. Some of it is good, some of it is bad, some of it has a purpose, some of it has none. I’m starting to sound like Dr.Suess with all of this, but this is how things are in our world of increasing internet and social media. So there seems to be a lot happening and a lot of people involved in the cause. This is great because getting people to understand the problem is one way to create solutions, as long as what we tell them is correct.

So what is my role in all of the workings of shark (and ray!) conservation? My job is to create information. This is one of the best parts of my job – getting to learn things that maybe no one else in the world knows. What then? Then I need to get the information written up and published so others can use it and learn from it. This isn’t just about telling other scientists what I learned, this is also about making sure people who make decisions about management get the new information if they need it.

There are so many questions about sharks and rays. So many things we don’t know. For some species we don’t know how long they live, how many pups they have, how far they swim, and even how many are there. We need all of this information. People who decide if it is ok to fish sharks and rays, or whether we need to make a marine protected area, need this information. If they don’t know these answers they can’t make good decisions because sometimes they’ll have to guess what to do. My job is to give them the answers so they don’t have to guess (as often, we still have to guess sometimes). This same information is also used by conservation groups. If a manager makes a decision that doesn’t match the scientific information then the conservationists can use the information I provide to try to change the decision.

So, it seems like I sit outside of all the action doesn’t it? I don’t make the decisions and I usually don’t challenge the people who make the decisions. Those are other people’s jobs. My job is to get the information or ammunition needed to argue or make decisions. So, does someone like me ever really make a difference? You bet. Work I did to define what a shark nursery is has been used to save habitat for Endangered smalltooth sawfish. My science is listed in the Federal Register in the protections for sawfish, a real world result of my science! My data from studying mortality rates of blacktip sharks has been used to adjust the number of blacktip sharks caught in US fisheries. This was an unexpected outcome of one of my projects, but one that proved very useful to managers. These two examples are not the things my research is most known for, but they are some of the bits I am most proud of – times when science made a difference.

Times are complicated and our oceans are damaged, but with hard work and good science I hope to continue to make a difference where I can. We need more answers to save sharks and rays, and that means we need more science.

Dr. Michelle Heupel releasing a young blacktip shark in Florida

Dr. Michelle Heupel releasing a young blacktip shark in Florida

An endangered smalltooth sawfish from southern Florida

SHARKS INTERNATIONAL 2014: A pivotal forum for science and conservation collaboration

Written by Hannah Medd

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Hannah Medd

Approximately 275 students and professionals from 40 countries descended upon Durban, South Africa, during the first week of June, 2014, to talk SHARK! The 2nd annual SHARKS INTERNATIONAL scientific conference was recently held over 4 days of about 80 talks on all aspects of elasmobranch research including acoustic telemetry, physiology, tourism, genetics, tagging, age and growth, fisheries, sensory biology, population ecology, Baited Remote Underwater Video Systems (BRUVS), trophic ecology, sawfish, social research, management, and shark control. It was a shark nerd’s dream and I jumped at the chance to go! Having attended graduate school in South Africa, it was a long awaited homecoming but also a rare opportunity to network with peers working around the globe, exchange ideas, collaborate, and finally meet face to face.

The talks were only 15 minutes long, which is not a lot of time to present the breadth of your work that for many is decades in the making so most presenters focus on their innovative methodologies or the latest results or most impactful applications. To further inspire the Gills Club members (not that the guys didn’t perform admirably) I noticed some impressive presenters that just happened to be ladies! Dr. Alison Kock, a Gills Club Scientist and Research Manager at Shark Spotters based in Muizenberg, South Africa, gave an impressive talk on her research on the white sharks of False Bay, South Africa, revealing the sharks demonstrate high levels of site fidelity (they really like to hang out in specific spots) to inshore areas which will affect how Marine Protected Areas will be designed. Charlene da Silva, shark researcher for the South African Fisheries Department, gave a funny and dynamic talk on the chondrichthyan fisheries of South Africa, the lack of data on economically important species and the immediate need for sustainable management. Rachel Graham, Executive Director of Mar Alliance, spoke on monitoring sharks using many different methods in Belize to establish a baseline which is incredibly important in informing conservation planning. Lauren De Vos, a PhD student from the University of Cape Town, spoke about her work using BRUVS (Baited Remote Underwater Video Systems) to assess abundance of sharks in different habitats. Alison Towner, a PhD student, described her work tagging and tracking great whites in Gansbaai, South Africa, to determine what environmental factors influence the sharks’ movements by collecting data on cage diving boats. Ana Sobral, a Portuguese researcher, represented the rays by presenting her work on the aggregating Mobula tarapacana near the Azores. Ana is developing a photo identification program based on the color patters on the rays’ stomachs to better understand the population dynamics of these little-studied rays. Sarah Fowler, the Vice-chair of the IUCN Shark Specialist Group, a legend in shark research and conservation, demystified the seemingly overwhelming process of listing vulnerable species on international treaties such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The formidable Sonja Fordham of Shark Advocates International clarified some common misconceptions about global shark conservation that can be spread by reporters and well-meaning concerned citizens, while encouraging a focus on the real threats to the vulnerable species, charismatic or not. These ladies represent a snippet of the incredibly impressive and inspirational female talent demonstrated at this conference.

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Charlene Da Silva

DSC_1273                                                                          Ana Sobral 

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                                                                                       Alison Kock 

The take home message was that shark research needs to focus on species other than the big, charismatic species like whale and white sharks and it needs to employ innovative techniques to achieve goals for broader conservation impacts. It was so encouraging to see and meet new fresh faces that are so dedicated to understanding the importance of sharks and rays to our ocean ecosystems as well as to learn from those professionals that have plowed the way for better research and conservation. From the welcome cocktail party, including fabulous Zulu dancers, to the each evening’s event, through the manic tea breaks, Sharks International 2014 was definitely considered a success!

                                     

Science versus cool; it’s not all diving with sharks

Written by Dr. Michelle Heupel

We’ve all seen the documentaries about marine biology and sharks. I grew up watching Jacques Cousteau (some of you will have to go look him up, but trust me he was a hero to many kids). Being a marine biologist looked amazing. Jacques and his crew went on these fantastic ocean explorations and saw all sorts of amazing fish. What’s not to love?

Nature documentaries have come a long way from watching Jacques in the 1970s. The video is better and technology has allowed us to get closer to more and more animals, but some of the impressions are probably still the same. I know this because a lot of students contact me and want to tell me right away how much diving experience they have. Too bad they probably won’t get to do much diving if they come work with me…. What did I think marine biology was about growing up watching these programs? Going to amazing places and spending a lot of time diving to study the fish. Boy was I wrong! Now I watch these programs and I think, how are those guys so clean?? When I’m in the field I am very regularly covered in mud, saltwater and fish guts. This is the difference between filming what I do and an average day in the field.

 beau

My friend and colleague Beau Yeiser after a day of work in the Everglades.

So what is reality? For many of us we spend much more of our time fishing and servicing equipment than diving. A day of fishing involves a lot of jobs that aren’t very glamorous. Cutting up bait and setting baited lines means you smell like dead fish pretty early in the day. Even wearing gloves can’t save you. I can’t count the number of sandwiches I’ve eaten while my hands stink from bait even though I’ve tried to wash them over the side of the boat. The objective of the day dictates how bad you smell when you get home. Tag and release is pretty good and fairly low on the stink meter, dissecting sharks to collect samples though is not. Dead shark is a pretty interesting smell and one that has to be washed off – how does that smell get into your clothes?

When we’re not fishing for sharks my team and I are downloading data from acoustic receivers that track shark movements. This often involves handling very muddy receivers and scraping off a lot of barnacles. Another pretty unglamorous job. This all sounds pretty bad doesn’t it? I come home stinking of dead fish, covered in mud, fish guts and whatever else I happen to get on myself during the day. They don’t show this version of things on TV unless you’re watching Dirty Jobs. What can I say except that the dirty, stinky gross jobs and long days on the boat are the best part of my job. This is really getting in and doing science. Cleaning the junk off receivers so we can get the data and see where our animals went is really cool even if it makes a mess. Learning new things no one else knows yet is exciting.

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The glamour of fishing – what you can’t see is one of my students holding onto my feet (so I don’t fall overboard) and the bruises on my ribs.

So what about all that diving I thought I’d be doing?  I’ve spent a lot of time studying coastal sharks in the tropics. The water is so brown and muddy you can’t even see your hand in front of your face underwater, let alone any fish. These days I do a lot more work on coral reefs. We can definitely see in the water, but unfortunately when we go diving we have a very specific job to do. When we download the receivers here the dives are short and targeted, not a lot of time to look around and be in awe of the reef. We do see sharks on some of these dives though and it’s always a treat to see them.

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Sometimes a shark swims by like this blacktip reef shark. It’s not very close, but at least we saw it.

So, science versus cool? Well I’m a nerd so I think science is cool. A day getting dirty and smelly on the boat is still better than a lot of other jobs I could have and I really do love it. This is a great career, just don’t count on staying clean or getting to dive all the time and you should be fine.

Rays need love too

Written by Dr. Michelle Heupel

I learned something new last year. I love learning new things, but I sort of wish I didn’t have to learn this. The International Union for Conservation of Nature (IUCN) has something they call the Red List. This is a list of all the species of plant and animal (or as close as we can get to all of them) and their conservation status. Scientists volunteer their time to assess species and the results are listed with IUCN. An analysis of the IUCN data for sharks, skates and rays last year revealed that 5 of the 7 most threatened families were rays, not sharks. And on top of that there are more threatened ray (107) than shark (74) species. Wow, who knew?

This result was published in a paper by Nick Dulvy and a slew of us who contributed to the listings (http://elifesciences.org/content/3/e00590). I think all of us were stunned to see that the rays were so much more threatened than the sharks. So what does this mean in the real world? It means we have been catching and removing a lot of rays without realising the damage we are doing to their populations.

imageA figure from Dulvy et al. 2014 indicating the families of greatest and least conservation concern.

How did this happen? Great question. Skates and rays are not as well studied as sharks. Maybe they aren’t as cool? Maybe they aren’t as obvious? The reasons why vary, but the reality is not many people have or do study them. One reason these species aren’t well studied is that they have never really been the target of fisheries. They are typically taken as bycatch, meaning they just come up in the nets or lines when fishers are trying to catch something else. Historically bycatch species were usually not well studied because they weren’t high value or important species. Many of the rays that are killed each year may not even be harvested for food. They may simply be caught in nets, die during the fishing process and get tossed overboard. This means we haven’t really understood how many were being affected by fishing. Another, and possibly very important factor, is money. It is easier to get research money to study a target or high value species, it is much more difficult to get money to study bycatch, although that is changing as we grow more and more aware of the importance of bycatch species.

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A giant shovelnose ray, one of the species with high value fins.

We haven’t done a good job of keeping track of what is happening with rays for a variety of reasons. In the meantime some rays have become pretty important to fisheries. For example, sawfish and guitarfish have some of the most valuable fins in the shark fin market. This means there is a lot of money to be made which provides incentive to fish these species, especially guitarfish. Sawfish, unfortunately are one of the groups that is worst off. These are amazing animals. A slightly flattened shark with a hedge trimmer for a nose! They use their nose, or saw, to whack fish and stun them or grub around in the mud for food. They are truly bizarre and beautiful. This really cool saw, however, means they get tangled up in nets very easily. Fishermen in the Gulf of Mexico used to kill them to get the out of their nets. And then there are the people who want the saw for a trophy. It’s surprising how many sawfish saws I have seen hanging on walls in bars, marinas, etc. When we viewed our current house the previous owner had a sawfish saw hung on one of the walls! All 5 species of sawfish are listed by the IUCN Red List as Endangered or Critically Endangered and their populations have declined around the globe. Australia is one of the remaining strongholds for many of these species, and in the US the smalltooth sawfish was the first elasmobranch included under the Endangered Species Act after their populations had declined by 95%. Recovery from such a large decline will be very long.

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Dr Colin Simpfendorfer releasing a smalltooth sawfish in the Florida Everglades.

So, we need to start doing a better job conserving ray species. They need to become a priority research area. We know very little about even the basic biology of many species and under the current circumstances that isn’t good enough. We can, and should, do better. So while campaigning for better conservation and management of sharks spare a thought for the rays. They need our help too.