I love the ocean, the smell of the salty air and spray of the waves as the boat rocks through the water. Despite growing up 800km from the nearest coastline it is when I am by the water, on the water or diving under the water that I am home. For my time at the Bimini Sharklab this becomes more fact than fantasy. Even on the rare days when I’m not out on a boat tracking, setting gillnets, longlines or snorkelling, the ocean is at my doorstep and is my backyard. It’s in this backyard and out on the water that the Sharklab lives up to its name. There is rarely a day that goes by that I don't see a shark. Currently my shark count is composed of lemon, nurse, blacktip, and tiger sharks but I have been warned of the bull sharks that frequent the Alice Town Channel and that December brings with it schools of hammerheads. Most sharks we catch require a work up, taking measurements, DNA and isotopepe samples and inserting one or more tags. The first shark I tagged was a blacktip shark. We had brought him up along the starboard side of the boat facing into the current. My colleague Marissa held the shark steady by his dorsal fin as Matt, the PhD candidate, talked me through the steps. The steps were simple really, line up the tag at 45˚ where the dorsal fin meets the body in the small dark incision Matt had made then give the casey tag loader a strong whack to insert the tag. My hand shakes as we sway in the waves and what should be a relatively quick and easy task seems daunting and endless. It’s funny how something as simple as Marissa regripping the shark and saying, “Don't worry, you got this” that allows me to still my hand and slide the tag into the proper position. With a deep breath and one more rock of the waves I slam my hand down and give the tag a pop. As Matt leans over to check that the tag is securely in place a huge grin appears on my face. Marissa and I exchange excited looks as I half whisper half squeal that I just tagged a shark! Excitement pulses through me while we finish the workup and release the shark and it fills me now just thinking about it. There is still a little over two months left in my time here and despite any fowl weather, 4am wake ups or the constant looming threat of mosquitos, I look forward to ever chance go get out in the boats and the prospect of seeing and tagging another shark.
Sixty-six years ago George Orwell portrayed in his novel ‘1984’ a fictional entity called “Big Brother” who is claimed to rule a totalitarian state, creating a society that is under total surveillance by the authorities. Citizens are constantly reminded of this by the slogan “Big Brother is watching you”, an aphorism which is omnipresent on screens. In modern human society, Big Brother is inherent to abuse of civil rights, specifically in terms of mass surveillance. As bad as this may seem for human populations, however, mass surveillance by telemetry is arguably the most important and potent tool ecologists and conservationists have to protect natural populations and their habitats in increasingly human-dominated land- and seascapes.
In early 2014, the Bimini Biological Field Station (BBFS) established our equivalent of ‘Big Brother’ – an extensive acoustic underwater listening array, placed strategically in Bimini’s diverse marine habitats to monitor the movements of sharks and rays, tagged with 10-year transmitters. Each animal’s tag broadcasts its acoustic signal, every 90s or so and if within range of a receiver (i.e. ~500m), its ID, date and time stamp are recorded. Data builds, from minute to hour to day, month to year across different tidal phases, seasons etc. For the next three years I will use this data to identify drivers of movement, habitat preferences, spatial hotspots and mechanisms of habitat partitioning for Bimini’s local shark and ray fauna.
Only a few months ago I arrived at the station as a Principal Investigator to lead this project and have recently summarized our last 18 months of data. Some 48 sharks and rays from 7 species were detected by Bimini’s “Big Brother”. Interestingly, my first exploratory analysis has revealed that some species show a diverse habitat range throughout Bimini (e.g. an adult lemon shark detected on 34 receivers), whilst movements of others (e.g. southern stingray: 7 receivers) are more confined. It also appears that some habitats off southwest Bimini likely function as important corridors or highways for shark movement, detecting 20-30+ individuals. Further, I excitingly received information of our sharks ‘making moves’ outside of our array. Two male nurse sharks were detected in Andros and Grand Bahama, as well as migrating lemon sharks between Jupiter (Florida), Bimini and Florida Keys.
Surveillance arrays like the one deployed in Bimini provide valuable information regarding behavior, habitat and space use of sharks and rays on small geographic scales. While this information is crucial for effective conservation of local habitats, information about movements on scales of areas, countries or even continents is paramount to protect the populations that occupy them to conserve them for generations to come. Hence, small receiver arrays are gradually becoming larger and connected to other receiver arrays, creating large geographic scale networks. So is mass surveillance all that bad? I guess it’s a matter of perspective.
Piece written for Save our Seas Foundation, and published on their website here too: http://saveourseas.com/update/mass-surveillance-not-all-that-bad/
What does one tropical storm, meeting the one and only Samuel Gruber, doing my first work up on a reef and nurse shark, my first shark dive, and learning how to fish for barracuda all have in common? Everything I have experienced during my first month living and working at the Bimini Biological Field Station (but believe me it doesn’t stop there). The hardest part is verbally encompassing all these amazing events and letting you in on the magic that the shark lab offers. So where do we start?
Well it begins with thinking you and your coworkers might be slightly insane. You’re there in the middle of the sea, it seems that all you notice are your fins slowly dangling back and forth underneath you and our heart rate beginning to increase. But cautiousness doesn’t slip to far from consciousness. You hold the line, prepare yourself, take notice of everyone else in the water, and wait for the bait to get thrown. And one by one they begin to arrive…
Five reef sharks showed up during my first shark dive. That was the first time I was in open water with a shark and it would take me .01 seconds to do it again. They swim around, agile, might come close enough to caress your fin but at the same time you just got close enough to touch theirs as well. Sure, I called my mom later in the week and told her I had been on a shark dive and it was entertaining to listen to her reaction, “What, are you guys insane?!” Yea maybe, but how can you do this job if you aren’t (at least partially)? But mainly it was about that sheer humbling feeling you get, the anxiety rush, and the amazement of being in the water with an animal that’s close to 430 million years old. To look at a living fossil, an evolutionary legend. It’s not about the bragging rights.
Image credit © Nick Luz