Wednesday, 11 December 2019

How to survive when your mother is a cannibal - by Clemency White

Few sharks in the world are as well understood as the juvenile lemon shark, and that is in a large part thanks to the extensive work done by Dr Samuel Gruber and colleagues at the Bimini Biological Field Station on the nursery populations that inhabit Bimini’s coastline. From life history and anatomy, to behaviour and learning, and more recently to proving their individual personalities, there is little we don’t know about them. Yet, while we are surrounded by hundreds of these tiny sharks year-round, we very rarely encounter them alongside their adult counterparts. There is very good reason for this: adult lemon sharks predate on these juveniles, and space partitioning is evolution's way of preventing the species from causing its own decline. But, in a lagoon full of predators, and without these larger and more experienced adult sharks around them, how do these small and na├»ve animals survive the extremes and dangers of Bimini?

Lemon sharks reproduce at the same time every year, which means we know they will predictably return to Bimini to give birth in the Spring. That is exactly what we saw this April, when we were lucky enough to capture five lemon shark pups immediately after their birth. As they wriggled their way through the water, struggling to orientate themselves, it struck me how vulnerable they seemed. And to some degree, they are – only 35-65% of lemon sharks will survive their first year of life here. Yet for a species with a conservative life history, maximising survival of pups is of paramount importance. Once we had captured the pups and quickly taken DNA samples and measurements, some of the fascinating ways ways these newborns are able to quickly adapt to the outside world became apparent.


Newborn lemon shark being born © David Doubilet


One of the most noticeable features of the neonates were their gummy mouths. Lemon sharks come prepared to predate with a full set of small needle-like teeth. But similarly to their dermal denticles and fins, which flap against the waters motion like tiny sails in the wind, they are uncalcified at birth – likely to save their mother some trouble. This makes them look non-existent, even up close. While we are sure there is no maternal care after birth, the open scar between their pectoral fins tells us that this by no means goes to say there is no maternal investment. Connected by an umbilical cord, up to 18 pups will grow and develop through direct nourishment from the placenta. This ensures that all 18 will be born with good survival chances at a length of 55-65cm, and weighing around 1 kilogram, capable of swimming, predating and surviving alone. This equates to a huge amount of energetic input by pregnant females. So much so, that it takes a year after birth for an adult female lemon shark to recover enough to reproduce again.


Newborn lemon shark pups  © Clemency White


Astonishingly, when we release all five of the pups into the mangrove nursery, where they will develop and grow for the next 13 years before they themselves leave Bimini, they are almost unrecognisable to the sharks we caught just 15 minutes prior. Calcification has occurred rapidly; their teeth are sharper, their fins more robust, cutting through the water like a knife. Their dermal denticles which were soft and slippery are now rough and textured and, as we watch them swim off into the tangled roots that will provide them valuable safety from predators, they swim strongly and effortlessly. A stark contrast to the dazed manner in which they swam away from their mother. This quick adjustment is another way that this species has evolved to “hit the ground running” without parental protection. 

This is just the beginning for these pups, even the largest of which seems only a sliver of a shark at 57.5cm. The lagoon holds extreme temperature changes, an intense tidal range, a host of habitats and a multitude of predators that they will have to navigate if not to perish. Yet, while it would be both unlikely and a shame for them to re-encounter their cannibalistic mother, they would certainly have a lot to thank her for in enabling them to survive that long.

All five newborn pups being transported to their mangrove nursery © Clemency White

Thursday, 14 November 2019

The Bimini People-Lab - by Joey Nolan

When I first learned about the Bimini Sharklab, I read through all of the lab’s research and was fascinated by everything. As I looked through different labs and scientists within the shark research world, there seemed to be an endless amount of connections to the Sharklab. The more that I learned, the more the idea of learning to conduct shark research there became my dream. Fast forward a few years, and I receive my acceptance email to be an intern for 6 months. In the months leading up to my time in Bimini, all I could think of was the sharks that I would be working with and the research that I would help conduct. I had no idea that after my internship was over, the sharks and the research would fall short in comparison to the best aspect of the lab: the people.

Do not misunderstand me; the sharks that I worked with and the research that I participated in was the stuff of dreams. I was able to swim with Caribbean reef sharks and great hammerheads, witness the placement of satellite tags on tiger sharks, tag and observe the behavior of countless juvenile lemon sharks, and participate in shark workups on several different shark species.

Preparing to insert a PIT tag into a mature nurse shark during a scientific workup © Sophie Hart

Although I will never forget these experiences, I will hopefully have a long and successful career working with sharks. What will always be completely unique to Bimini is the friendships that I found at the lab and the memories that I made. I will never forget unknowingly eating potatoes that were dug out of the sink drain, or all of the laughs that we shared while building our pens. I loved staying up all night long talking, laughing, and dressing up to re-enact sawfish workups during the annual PIT survey. People nowadays laugh as I explain to them how we would sing the Pirates of the Caribbean theme song whenever we were out on the water in significant waves or rain, or how we wore eye black on the first few nights of PIT to look serious. Whenever we got caught in a downpour, we would pass the time by yelling at the storm, or trying to build a fort on the shore to use as shelter. Situations that some people may not have enjoyed were the ones that really brought us together. Spending every waking second with your co-workers can be a recipe for disaster in some professions, but at the Sharklab it made for some of the greatest memories of my life.

The lab was also much more to me than just a place to have fun. Many people at the lab inspired me to continue on the path of shark research as I observed their dedication and passion for their work. Every time I spoke with our CEO Matt, principal investigators Vital and Clemency, or the many visiting scientists that came through the lab about their research, it made me more determined than ever to work on research of my own as they are doing now.

These stories barely scratch the surface of what an incredible impact everyone at the lab had on me. I made some friends that I am very confident I will keep for the rest of my life, and that is what made my time at the lab the greatest that it could have ever been. It has been a few months since I left Bimini, and at some point during my day every day since I have thought about the lab and wished that I could go back. But my fellow former-interns and I must push forwards in our careers now that we have moved on from our internship, and I am very excited by the prospect of working with any of them again. The Bimini Sharklab is a truly wonderful place, and I cannot wait to see if my career takes me back. 

Monday, 21 October 2019

A family day to remember - by Leander Harlow

Spending two months living in confined quarters with twenty-something people is enough to drive anyone mad. On the other hand, and perhaps more importantly, it’s conducive to creating long lasting connections and friendships based on mutual passion. So, when the time comes for a volunteer swap, emotions are running high. To honour this, one of the many traditions at the lab include “family day” where volunteers are able to spend the day together, making the most of our time left in the vortex that is the Sharklab.

Family day came around way faster than anticipated and although it meant many were soon to leave the lab to return to ‘normal’ life, everyone was eagerly awaiting the itinerary. It was decided we were heading out to Honeymoon Harbour, a site people visited to have close-up encounters with Southern Stingrays, and then bull shark fishing at a nearby neighbouring island, Cat Cay. To say we were excited was an understatement. 
Our first stop of the day at Honeymoon Harbour provided plentiful giggles feeding stingrays in the shallows. We weren’t sure if the rest of the day would match up to this wonderful moment but boy, were we wrong.

 A southern stingray glides over the sand © Sophie Hart
Hopeful to catch and tag a bull shark, we made our way over to Cat Cay marina as we had heard sighting reports from previous days before. After a couple of hours baiting unsuccessfully, one of the locals offered to fly his drone in an attempt to help us scan the area, but sadly there were no bull sharks in sight around the island. However, we did spot a dark patch moving slowly in the marina. Zooming in to investigate, much to our disbelief, we found out that it was in fact a manta ray!

We promptly got our gear together and slid into the water. For the next 10 minutes we were lucky enough to dive with this gentle giant in the shallows, and slowly helped guide him out of the marina, where he was obviously lost. It was the most surreal experience and the ‘surprise’ sighting definitely made our day, if not week.

Manta ray (Mobula birostris) in the shallows © Rosie Poirier

Ready to head home we packed up and began our journey back to the lab, but the excitement didn’t stop there. We saw a tourist boat driving straight towards us, only to shortly realise they were following a pod of dolphins. First a manta ray, now dolphins! We were ecstatic to say the least. We got in the water again and had another wonderful encounter with these gorgeous, inquisitive creatures. This truly had been a day to remember.

Sunday, 29 September 2019

Shark rescue at Skittle Alley - by Ben Reilly

Today has been the best to date - our aim was to catch lemon sharks larger than 1.2m for visiting scientist, Evan Byrnes, who is using respirometry to study metabolic rate in sub-adult lemon (Negaprion brevirostris) sharks.
We started the day slowly baking in the sun but protected by the shore from the wind. We chose a spot where the water rushes out of the mangroves when the tide is falling, the theory being that as the water became shallower the prey would be forced to the fringes of the mangroves, thus less protected and more vulnerable to attack from larger lemon sharks.

We had interest immediately, in the form of juvenile lemons and a nurse shark, which were not what we were looking for. The tide slackened off and the water barely moved. We decided to move 50 yards west to another outlet where our chum could flow out to sea, enticing all those with good smell to our drive thru! Again the juveniles hounded us and with the sun reaching its peak ferocity and the wind whipping up we all started to lose hope and patience. Evan offered round his Skittles to his demoralised crew. Ryan, another volunteer, dropped one into the bottom of the boat which had a slurry of fish blood and guts in the bottom. Upset that he had let this tasty morsel go he gifted it to the shark gods and prayed for a lemon. Almost as if the lemon god had heard us an overjoyed Ryan shouted out, pointing in the direction of a good sized shadow. Within minutes, the little beauty was caught and pulled in to the edge of the boat, tail-roped and held in position by its dorsal fin. A quick measure to check his size and at 125cm, he was big enough for trials. We wrapped a DIY stretcher under the shark, pulling 2 poles together and lifting him up in the hammock from the water to a transport tub on the boat. The hook was quickly removed before we took a 5 minute journey back to the Sharklab beach, where the reverse stretcher technique got him safely into a semi-captive pen. After a few mandatory high 5's we returned to what we had now christened 'Skittle Alley'.
We returned to find a second lemon shark already hanging around our bait box. We set the lines and waited. Before long, number two was in the bag, just marginally bigger than the first at 127cm.
It was getting late and we were ready to pull the lines when Riley, a fellow volunteer with her feet dangling in the water, noticed something swim underneath her. Feet quickly out of the water we all dashed to look. With the sun setting and the wind breaking the surface it made it difficult to work out. It was a shark but we were unsure of the species - it was big and odd. Assistant manager Hannah realised that the shark had got something wrapped around it.


Metal gasket found wrapped around the 125cm lemon shark (Negaprion brevirostris) © Ryan Cake

It was a lemon, but not as we know them. Time and time again he circled, dragging up sand as he went along. Still no one knew what the obstruction was. We agreed dinner, now waiting for us, would have to wait a bit longer. We were going nowhere until we had freed this shark. Finally he bit, and we got him to the surface only to reveal a metal gasket, a thin piece of metal that goes between the top and the bottom halves of an engine, was stuck around the pectoral fins and up to the dorsal fin. The damage caused by this man-made product wasn't immediately visible until we managed to cut it off. We grabbed a camera to document the injuries as they unfolded. We managed to cut the loop encompassing the body off and gently peeled it away until we got to the pec fins, where we had to slide them an inch out of the tissue - it had cut in like razor blades.


Laceration from the metal gasket on the belly of a lemon shark © Ryan Cake

Having trouble freeing the loop from the sharks belly, we turned him into tonic immobility and were aghast at the sight of an inch-deep laceration around the circumference of his girth. The metal gasket only held in one place, from skin that was healing over the top of the metal. Enveloping the foreign object, obviously this shark had worn this necklace for some extended period of time. Finally he was free and with hook removed, he swam away strong.

This shark was previously caught and tagged in April 2018, so it will be interesting to see if we meet him again and to see his recovery. Evan was in no uncertain terms sure that he would now make a full recovery. We returned for dinner, story telling and bed with a good feeling of having helped one of god's creatures out!

Smiles all round after freeing the shark!  © Ryan Cake

Thursday, 12 September 2019

Tiny tiger on the line - by Rosie Poirier

Arriving at the airport to the Sharklab and meeting the five other faces with whom I’d be spending the next two months, five girls whose passion for the oceans had brought them to the Sharklab, none of us sure what to expect, but we knew we were excited. We boarded a small plane that would take us to a remote island and to the Sharklab we had all heard so much about and were ready to learn and to contribute to.
Arriving we found ourselves amidst power outages, island-wide fuel shortages and mosquito swarms and realised that despite everything the Sharklab carried on, because the natural world out there didn’t stop, and so neither could we. We had come to contribute to an ongoing legacy of shark and ecosystem research that the current staff and all those who had been a part of the Sharklab for the past thirty years had been contributing to, and we were learning that with field research comes a lot of diligent, creative, fun, exhausting and exhilarating hard work. Field research bends the confines of society’s boxes that tell you your workday starts at 9 am and ends at 5 pm and your work stays within those hours. Marine science asks that you are ready to observe at all hours of the day, to witness the world of nature and the mysteries of the lives within it. And if you want to witness it, record it, understand it, and share knowledge with the outside world then you have to bend those societal work confines and be ready to be out there any time of the day or night, through the rain and the hot weather, in the night and in the early mornings and be ready to see things that few others may have ever had the chance to see.
My once in a lifetime moment came as I was going out for my first longline check with the Sharklab. These research longlines are put out once a month to contribute to shark population research and once set, needed to be checked every four hours for 24-hours. My group’s assigned time to go out was 2 am, a time I was quite excited about since sharks are more active at night and I figured I’d be more likely to see something. We woke up and headed aboard the boat in the dead of the night with lightning flashing in the distance, to check the five longlines. The previous group had seen four sharks during their 10 pm check so we had high hopes. We checked the lines quickly without seeing any sharks and I started to feel disappointment as we neared the end. This would have been my first longline shark work-up and tagging but now it seemed like we wouldn’t be seeing any sharks. We passed by a section of the line and nearly missed the shark caught in it because it was so tiny. We pulled up alongside to see the little body of a juvenile shark with the most beautiful dappled patterning along its body.

Juvenile tiger shark caught on a scientific longline  © Sophie Hart - BBFSF

My heart skipped a beat as I realised I was looking at the shark I had dreamed of seeing for so long, a tiger shark, and realised that my first encounter with one was nothing as I had imagined it would be. Not a large, imposing predator in front of me, but just a tiny shark trying to survive the first year of its life. We worked up the shark alongside the boat and I held the dorsal fin to secure it while it was measured and tagged. The little shark was 73cm long and perhaps the smallest tiger that was ever seen at the lab. Clemency, our principal investigator aboard the boat said we’d be lucky if we ever saw a tiger that size again in our lives. They are very rarely seen and somehow, I had been blessed with this precious moment. A moment that would have never been experienced had I not been up at the middle of the night seeking to advance and increase our understanding of sharks and the natural world that we all share.

Sunday, 25 August 2019

Surreal, uncomfortable, but definitely magical - by Ryan Cake

There's something surreal, uncomfortable but definitely magical about something you know will never happen again. 
The Shark Lab's annual juvenile lemon shark survey (more commonly referred to as PIT), as the name suggests, happens every year from the end of May until mid-June. 12 nights, 144 hours, 2 nurseries and 4 crews made up of staff and volunteers, some of whom know what's about to happen from previous years.
Months of preparation have lead us all up to these crucial few weeks in the Shark Lab calendar. Days spent moving and building holding pens, fixing nets and of course gillnetting until you'd be comfortable taking a shark out of the net blindfolded (which we never do and isn't recommended).
Night 1 arrives and everyone on Net 3 of the shark land nursery has a rough idea of what's about to happen. This net has a history of being the busiest from start to finish, with sediment that can go over your knees and water so shallow at times, your boat could be stranded. Nevertheless the net was set to cheesy 80's music, courtesy of our home crew, and all we had to do now was carry out our checks every 15 minutes to see if we had something in the net. 

Walking the gillnet - © Sophie Hart - BBFSF
Needless to say, we hit 3 minutes and we are met with the sound of the net splashing in all different sectors. Transport tubs and scissors in hand, 3 of us ran as fast as our sediment-buried legs could carry us to the source of the splashes – there are 8 sharks in our net. 4 hours later, we'd counted 20 sharks and it was eventually time to carry out a “normal” check of the net.
By the end of night 1, Net 3 had caught 30 sharks, bringing the first night's total to 51 across 3 nets. We're exhausted, tired, hungry and maybe a bit delirious, yet so hyped up on adrenaline from the chaos which has just happened. The other 12 nights yielded many more crazy moments, from catching a tiny juvenile blacktip (C. limbatus) shark in our net to hunkering down and later abandoning our last night early after the largest lightening storm I've ever witnessed passed over us in the North Sound of Bimini.

Rarely seen in Bimini, a juvenile blacktip (C.limbatus) caught in the gillnet - © Sophie Hart - BBFSF

188 sharks and countless incredibly creative food-run costumes later, we'd finished. Wet, tired and definitely delirious by now, we finished PIT 2019 in style (possible lightening flashbacks aside), knowing that the memories you've made in those 12 nights will be with you for the rest of your life.
That's the beauty of PIT – you spend all the nights with the friends you've made in your time here at the Shark Lab, laughing, swapping stories and most importantly contributing to something that's greater than yourselves. The beauty of PIT is knowing that these people, in this place, telling those stories, laughing at those jokes whilst catching hundreds of lemon sharks will never happen again – and you treasure it forever.

Net 2, North Sound, nights 1-3 crew © Sophie Hart - BBFSF

Tuesday, 30 July 2019

Being at the Sharklab while on the Autism spectrum - by Maddie Koeplin

I’m not supposed to like erratic schedules, or having plans change on a dime. That is a common trait seen among people on the autism spectrum - including me. Biology, especially field biology, is full of changing plans, missing equipment, nothing going right, or nothing happening when things do go right. That is life at the Sharklab - and I love it.
I knew I wanted to be a biologist since I learned the meaning of the word in it’s most basic sense (the study of life) at age eight, years before I was ever diagnosed with ASD (autism spectrum disorder). Biology, especially zoology, became my all- encompassing passion in life, which is what ultimately lead me here, to the Sharklab. Being around people as passionate about sharks and conservation as I am, and working with those people to meet common goals is thrilling and far outweighs my discomfort in the fact that the lab is crowded and, often, very loud.

I have the same start of the day as everyone else. I get up at the knock, eat breakfast while barely awake, get dressed, take care of the boat I was assigned to, and wait for a staff member to tell us the plan for the day. It’s routine. Mental preparation is key for me, so knowing what the plan is for the day is almost a necessity. If we are going out on the boats for anything, I get myself prepared for the fact that there will be a lot of vibrations, noise, and being squished together. I love going out on the boats, and that love makes the discomfort worth it. If I’m giving a tour, I go over what I need to say, and remind myself I need to ask the people on the tour what they are interested in learning about. As nerve-wracking as tours can be for me (speaking to people I don’t know is something I have a hard time with), it’s actually a chance for me to talk about something I have a lot of passion for without people zoning out on me.
 
© Karlee Orvis

Life at the Sharklab is hectic, loud, crowded, and disorganized - no matter how often we reorganize the lab and kitchen. Life at the Sharklab is also incredible in all the positive ways. There is always more laughter than complaining (sometimes the only way to get through the fifth thunderstorm you have spent in the mangroves is to laugh about it). Even though I find certain things uncomfortable that most people don’t, I wouldn’t have the Sharklab any other way.