Sunday, 9 December 2018

Lucky gangion #15 - By Molly Kressler

Professional athletes speak often about the adrenaline high that carries them through challenging periods of athleticism. Ask a member of the Shark Lab to describe a longline-caught shark-workup and you will find the response matches the adrenaline-fueled recounting of professional athletes.
At the Shark Lab, you are extensively trained in shark handling and work-up procedures before you are involved with such an adrenaline-fueled act as a longline check and work-up. As a repeat Sharklab volunteer, I knew the exciting possibilities waiting for me on a 20:00 longline check. Making her way out the channel and around the eastern tip of South Bimini, Twin Vee carried us to the lines set across the mouth of the Bimini nursery. Sighting the first float of the first line, the adrenaline begins to slowly leak, as you acutely survey the line for missing or submerged gangions. Like the pro-athletes would describe, it’s muscle-memory: holding onto Twin Vee’s rail while leaning out to sight each gangion, or as we all hope, to not sight one, the gangion float having been pulled under by the weight of one of Bimini’s several possible shark species.
To the astonishment of the crew, we had three blacktips (C. limbatus) that night, all caught on the fifteenth gangion of their respective line. By the time we finished the first work-up, the air was palpably buzzing, smiles and high-fives were shared by all. But with the shark safely off the side of the boat, the adrenaline began to slowly dissipate, and the attention was returned to scanning the lines for another submerged gangion.

A blacktip shark (Carcharhinus limbatus) being worked up during a longline check.
Photo by Sophie Hart | © Bimini Biological Field Station Foundation
When we came upon the second black-tip, again on gangion #15, the buzz returned. Flood lights on, the team moved swiftly to bring this female up to the side of Twin Vee. I elected to hold her first dorsal fin, working to secure her position in the water, so the rest of the team could perform the various work-up measurements and samples as swiftly as possible. It was holding this female’s dorsal where I had a unique opportunity to see very fresh mating scars. The female’s dorsal side was littered with bite-marks. Elasmobranchs can heal their wounds remarkably fast; this female’s wounds hadn’t healed over yet, which indicated the mating event had occurred recently. Moments like this, a shark less than a metre from your face, with the types of ecological evidence you normally would only be able to see from metres away, are the adrenaline-filled moments that litter your months at the Sharklab.
The night proceeded with a third blacktip on another line’s gangion #15 – the boat erupted in astonishment. Smiles and laughs quickly turned to well rehearsed action, as another episode of swift data collection was underway. Eight minutes blitzed by and with another successful work-up complete, so too another blacktip swam away from Twin Vee, an official member of the BBFSF tagged-elasmobranch club.

Tuesday, 27 November 2018

Beyond the Tag - By Clemency White (Principal Investigator)

When you think of what shark scientists do, it usually conjures up images of tagging sharks and tracking them. Your mind immediately goes to the classic images of a team of scientists working quickly to tag and release huge sharks, it’s always a beautiful clear blue day, there are high-fives all round as the shark swims away with its new tag in tow. But how often do you consider what happens after that? How do we use the data that we get from tracking tagged animals to inform science? Welcome to Bimini...!

The Shark Lab team perform a work up on a Tiger shark (Galeocerdo cuvier) captured on a scientific longline.
© Sophie Hart / Bimini Biological Field Station
Since 1992, under the watchful eye of Dr Samuel Gruber, scientists at the Bimini Biological Field Station, “Shark Lab”, have been using data from tracking tagged sharks to answer a whole host of questions. We know that juvenile lemon sharks can swim back to their nurseries from as far away as the Gulf Stream. We know that space use is tidally linked, and juveniles will change their space use depending on whether or not predators can access the habitat they are using. We know that while adult females use Bimini to give birth, males are transient, rarely returning to Bimini after they reach sexual maturity. All of this is made possible by analysing the data obtained from tagging and tracking, particularly in long ranging marine species where physically following them by drone or boat is near impossible.

A juvenile Lemon shark (Negaprion brevirostris) swims by at one of Bimini's mangrove nursery areas, Aya's Spot.
 Sophie Hart / Bimini Biological Field Station Foundation
Over time, these datasets become even more valuable, and that’s where I come in. One of the reasons Bimini is such a special place is because of the long-term data that has been consistently collected in a standardised procedure for almost 30 years. Collating and analysing this data in one go allows us to confirm trends we have proposed from shorter studies and make new suggestions based on temporal change. While it may not be as glamorous as spending every day out on a research vessel in the Caribbean, there is a lot to be learned from spending your time running statistical models behind a screen.

During the two months I spent working on a dataset that spanned 26 years, surpassing my own age, I employed a statistical modelling technique that allowed me to see how different groupings of lemon sharks were using space. Most profoundly, I established that the space available for use by lemon sharks was reduced as a result of industrial development in Bimini. A thorough understanding of a species life history is imperative for sound conservation management techniques, and so studies like this one are instrumental in translating science to policy. This also highlights how important it is that we continue to tag and track sharks at all life stages.

So, next time you see one of those awesome pictures of sharks being tagged, consider the questions that the tag itself can answer, and how we can move forward in science and conservation - even after that shark swims far out of sight.

Tuesday, 20 November 2018

‘Turtle Day’; A visit from the FSU MTREC group - By Amanda Schadowsky

August 23rd, 2018 was the same as any morning at the Shark Lab, but for me it will forever be referred to as ‘Turtle Day’. We had visiting research assistants at the lab, from the FSU Marine Turtle Research, Ecology and Conservation (MTREC) Group, who took volunteers with them each day to assist in the field. On this particular morning a fellow volunteer and myself were selected. I was very excited because this was something new and I assumed that all the work I would be doing here was going to focus only around sharks.
After breakfast we got ready for working out in the field and grabbed the equipment we needed. We packed up the skiff and took off for the day to Bonefish Hole, a new location that I had yet to work at.
The sun was out in full effect surrounded by a picture-perfect blue sky and minimal clouds. The water was so clear, and the turquoise and blue color gradients starting from the mangrove edge was a perfect representation of the Bimini waters. I remember thinking to myself that the view was insane, and I couldn’t believe that I had the opportunity to live and work in such a beautiful place. 

As we were entering Bonefish Hole we were told to scan the water for green sea turtles (Chelonia mydas). This is where polarized sunglasses are important, so when the Shark Lab advises you to bring them, do it. The combination of the sun glare and waves makes it hard to see if you don’t. If we saw a turtle, we were instructed to point it out and the chase would begin! The turtles would try a few different tactics to get away, weaving, changing direction quickly, and sometimes completely stopping, camouflaged in the sea grass. They were quick, and we were on a small skiff, so it felt like a high-speed chase in an action movie. Once the boat was close enough, someone would shallow water dive off the front-side onto the turtle. Us volunteers were given opportunities to dive and try to catch one; unfortunately we were not as successful as the professionals! 

FSU MTREC researchers Alexa and Anthony take measurements on a green sea turtle (Chelonia mydas) during a work-up.
Sophie Hart
Once we had a few turtles in the boat, we then did work-ups on them. Measurements were taken along with small biological samples. While one turtle was getting worked-up the other turtles would make their way to the front of the boat, seeking refuge from the sun under my legs in the shade. It was truly a heart-warming moment to be near sea turtles. After the work-up was done, we were able to get photos with the turtles before releasing them. 

Turtle Day wasn’t an intense day. It wasn’t a day swimming with Bulls, Lemons, Reefs, or Tiger sharks. But, it was a day I will never forget.

Tuesday, 30 October 2018

Capture, Work-up, Repeat; a day in the life of a Shark Lab intern - By Laura Manning

The plane was boarded and it was time for our flight to Bimini. I peered down upon crystal-clear blue water and thought about the adventure I was in for. The past three years of my life, I have traveled around a variety of countries, each with their own unique species of flora and fauna I have had the opportunity to work with. I decided to come intern at the Shark Lab to gain even more field research experience.
We were given instructional classes by the staff the first week to help train us for tasks we would be doing out in the field. These included boat class, knot tying, and my personal favorite, shark handling. This class consisted of each intern demonstrating the proper way to hold a baby lemon shark. Being able to properly hold a shark is essential for capturing and performing work-ups on the shark.

There are a variety of capture methods used depending on the target species. To catch nurse sharks, the technique we use is called “nurse wrangling”, where we take a skiff out to reef ledges. Our goal is to find a young nurse shark typically between 50-80 centimeters total length that we can bring back to the pen to work-up. If we do find one, someone will free dive to the ledge, place their hand between the gills and pectoral fin of the shark and swim it up to the surface. It will then be placed in a tub of water and taken to the pen at the lab.
Scanning the reef ledges for juvenile nurse sharks.
© Sophie Hart

Stingray capture is definitely a “practice makes perfect” kind of a job. It requires one person to slowly drive a skiff along the mangroves and have 3-4 people standing on the bow of the boat scanning for stingrays. If a ray is spotted, the driver needs to steer towards the mangroves so that the others can jump in with dip nets to corner and capture it. Often, the ray will bolt or make circles as the skiff is attempting to follow it. The rays’ coloration provides a great camouflage with the murky mangrove waters, so spotting can sometimes be quite tricky. If a capture is successful, we place it in a giant tub filled with water and drive it to the pen to be worked up a few days later.

Gillnetting is the best way to collect juvenile lemon sharks for research. The gillnets are strung across the pond from one side to the other, with two people taking a bucket and walking along the net scanning for sharks. We do this every 15 minutes over the course of a few hours. If a shark is caught we rush over to it to quickly release it from the net, place it in the bucket and take it to the pen. If the capture is successful, we will perform the work-up within a few days. Until then, we will gill net fix! The holes are often large and fixing them requires a ton of mono and sitting in the sun making numerous fisherman’s knots, over and over…..

While these tasks can be difficult and tiring, they are all an important part of field research and are essential to better understanding elasmobranch species. Each day at the lab we learn something new and are able to continuously apply the skills we learn throughout the course of the internship. I can safely say I have learned so many techniques that will help me to become a better field scientist for any future research that I pursue.

Monday, 12 March 2018

The rest is ancient history - By Ko Chuan Yang

The rest is ancient history.  
What first races through your mind when you're given the opportunity of a lifetime? Exhilaration, excitement, euphoria. Then anxiety, expectation and self-consciousness. As the emotions settled and the news came to bear and the initial ecstasy of acceptance ebbed all that was left was doubt of my self-worth and whether I'd be cut out for something like this. How was I supposed to use my BA Hons in HISTORY effectively at a shark research station? How'd I even land the gig? Spiralling into self-pity I miraculously managed to catch myself. My focus had been on my inadequacies but they had nothing to do with why I'd been selected to intern at the lab in the first place. People don't dole out opportunities like these carelessly and presumably they must've seen something in me that would be valuable to the Lab. I won't repeat to you the list of strengths I muttered to myself in that moment of reassurance as that would be ridiculously indulgent and I'd get ripped to shreds by the others here at the Lab. But if you are interested in my background check out my profile on the Shark Lab website *plug* or even my Instagram (@ko.away) *plugplugplug*.  The 35 hour journey from Singapore was an emotional rollercoaster climbing to wide grins and plunging to nail-biting nervousness.
Upon arriving I realized the needlessness of my worry. Sat around a set of plastic tables introducing themselves before dinner was one of the most diverse group of people I'd ever had the privilege to meet. Fishermen, project students, aspiring conservationists, photographers, researchers, aquarium mermaids, parasail operators and even a cook. Teamwork makes the dream work, I thought to myself a few days later, seeing how everyone had been picked and a group assembled that was so capable in so many different things and ways that we seldom found ourselves wanting. So then.. what would I like to say to you, dear reader, perhaps an aspiring volunteer or an avid fan of the work that is done here at the lab? I'd like to say that the Shark Lab, as amazingly unique a place as it is, demands all the same things from you as the regular workplace. Commitment, determination, respectfulness and adaptability. What sets it apart then, is that as I've practiced these values here at the lab, I've learnt more about not only shark research and fieldwork (which is pretty easy when you start at about 0) but also about myself than I have anywhere else before. The people working at the lab are inspirational in all senses of the word, from their infectious passion for the ocean to all their diverse strengths and admirable characters, they provide you with a bottomless pit of knowledge that you could plunge into and use to constantly better yourself.
Eight weeks ago I took a deep breath and dove in, and the rest is ancient history.

Happy volunteers after beautifully repainting the Sharklab!

Thursday, 7 December 2017

Oh, Those First Days... By Kinsey Matthews

“Are you going to survive here?” Chelle, our media manager and one of my new roommates, took in my puffy and swollen body with concerned eyes. Despite my hardest efforts, tears leaked out of the corner of my eyes. Fresh off the plane that landed moments ago on the small island of Bimini, I discovered I was allergic to mosquitos. The new volunteers, eager and looking for adventure, went for a stroll around the island. We were instantly swarmed by the tiny creatures. Cursing and swatting at our heads like madmen, we sprinted back to the lab. Our bodies were riddled with angry, itchy, red bumps. I counted over 50 bites on my face, shoulders, and legs. My reaction was particularly bad, so much so that one of the older volunteers referred to me as “the one with the bites” before they learned all of our names.

In all honesty, that question terrified me. Not just because I couldn’t imagine having this reaction to mosquitos every day, but because I had little to no experience with elasmobranchs. I had no idea what I was doing. What was a longline? What the heck does a BRUV mean? And why do all the volunteers groan when the staff mentions gillnet fixing? It was obvious the extent of my shark knowledge stopped at the end pages of a textbook.

One of our first activities as new volunteers was a reef shark dive. It was my first time swimming with sharks. Seeing them in their natural habitat, without layers of glass between myself and the sharks, was exhilarating. Our lab manager Ben threw chum into the water, and the once calm Caribbean reef sharks swam in an absolute frenzy. But instead of glass, the only object between us and the sharks was our flimsy looking fins. Adrenaline pumped through my veins. It was slightly terrifying, a little alarming, and utterly magical.

Caribbean Reef Shark (Carcharhinus perezii). Photo (C) Chelle Blais 

During our second week, we set out longlines. I snipped a fin clip from a juvenile tiger shark, attempted to insert a Casey Tag into an adult nurse shark (man those guys have thick skin), and stared with wide eyes as one of the assistant lab managers surgically implanted an acoustic tag into the abdomen of an adult female tiger shark. On our way back to the lab, with the sun setting and our clothes thrashing in the wind, all four of us whooped and hollered. We had just won the lottery.

A month and a half later I can say I’ve learned more during these past few weeks than I have during a few of my undergraduate courses. I can confidently work up a juvenile lemon shark, including taking fin clips for isotope and DNA analysis, body measurements such as length and girth, and sex ID. I know that gillnet fixing includes boiling in the hot sun, sweat dripping from every pore of your body as your fingers fumble to tie a double sheet bend knot. I’ve learned that watching BRUV’s (Baited Remote Underwater Video Stations) videos can be one of the most mundane tasks to one of the most thrilling as you watch a tiger shark rip bait out from a cage. Through trial and error, I now wear copious amounts of sunscreen, even on cloudy days. I’ve realized the importance of protective clothing and layers upon layers of DEET (pro tip: the “natural” stuff does NOT work) to ward off the dreaded blood sucking monsters we call mosquitos. Most of all, I’ve learned that I still know nothing. Whether it be how to decipher the acoustic pings of a tag implanted in a juvenile lemon shark during tracking, or the location of the snips that we use for gangion fixing, every day I’m discovering something new.

Volunteers Kinsey, Molly, Rebecca and Sophia catching a southern stingray to PIT tag and release.