Tag Archives: tagging

Fishing blues

It was our first day tagging. I was nervous and excited.

Seven- to ten-foot oceanic whitetips dwarf the baby lemon sharks and bonnetheads I tagged last year. Tagging these larger, far more dangerous, animals requires a lot of skill and knowhow. Good thing the experienced SEA Collaborative (Shark Ecosystem Assessment or SEAC) researchers were running the show! Most of these scientists have been friends since graduate school and have been tagging oceanics for over five years, with many years of planning beforehand. This well-earned trust is relied upon when handling these big sharks: team members know each others’ movements; thoughts — and tagging a shark takes on the air of a well-choreographed dance.  I am learning from some of the best in the field.

Within two minutes of chumming, a ghostly grey shadow moved languidly: a broken, unsure shape glimpsed through the choppy blue surface of the water. A telltale dorsal fin broke the surface. Shark.

Delight burst through me. I jumped up to take pictures and chase the 8 ½ foot shark along the side of the boat. I took over 50 pictures in a minute.  I felt like I was 5 years old again, seeing a pile of perfectly wrapped presents on my birthday.  I thrilled with excitement, awe, wonder. But, as I looked around excitement waned and there was a quiet disappointment seeping from the team. Even from afar, they could tell this wasn’t the one we were looking for, not the infamous oceanic whitetip, just a blue shark.

Blue sharks are commonplace in the waters off New York where I am from. What was it doing all the way in the Caribbean?

As it turns out, blue sharks have the widest range of any shark species. Usually they prefer cooler water and frequent greater numbers in higher latitudes. Whitetips rule the ocean down here.

The shark was a she. On male sharks there are two short appendages that look like white asparagus stems used for mating attached their bottom (pelvic) fin called claspers. Clear evidence of mating scarred her side: a round ring of gashes in her skin made by the teeth of an amorous male blue shark no more than two weeks ago.

Mating scars on a blue shark. Photo credit: Andy Mann.

Female sharks are actually born with thicker skin than males because they need to withstand the vicious pleasantries of mating. Males bite down hard, curl around the female and rotate her on her back, which puts her in an almost hypnotic state called tonic (a handy method we also employed when working on sharks). They then use their claspers to fertilize her.  Usually the scars heal up in about a month.

Blue sharks and oceanics are very different. But, unfortunately, they share two things in common: they are both targeted in the shark fin trade and often mistakenly killed on hooks and lines meant for other fish.

But why is the oceanic whitetip endangered, and the blue shark not?

Fundamentally the blue shark is much hardier. Many sharks die when accidentally caught on hooks of longlines set out over miles of ocean to target such fish as tuna. Called “bycatch,” this unnecessary killing happens when one species ends up dying from fishing that targets another species. Blue sharks have a much higher survival rate as bycatch when they are caught on the longline. They also reach sexual maturity around 6-8 years old, which is young compared to other sharks.  Perhaps more importantly, blue sharks have lots of babies (called pups!): around 20-50 each year compared to 2-14 for an oceanic whitetip.

Even though they make up about 40% of the shark fin trade, blue sharks are technically sustainable, teetering right on the edge of maximum sustainable yield. There are just enough blues born into the population each year to replenish the ones that die.

After a recent trip to Hong Kong, where 50% of the shark fin trade takes place, Debbie Abercrombie, one of the shark scientists, exclaimed “I can’t even believe there are still blue sharks swimming around in the ocean anymore!” She described four two-story malls filled from top to bottom dried seafood products, “…with bags upon bags of shark fins from mostly blues and some oceanics!”

Blue shark being tagged.  Photo credit: Andy Mann
Blue shark being tagged. Photo credit: Andy Mann

Close encounters

Today I faced one of the most dangerous sharks in the ocean.

It was terrifying. It was absolutely beautiful.

And surreal.

I was above myself, watching a movie, not really there. She looked at me and I looked at her, our eyes locked. Suddenly she was real, she was there. So was I. I gasped through my snorkel. My heart raced. My mind flooded. Was I in the water with an oceanic whitetip? What was she thinking, feeling, wanting from this encounter? Was she really turning and swimming right toward me?

Swimming with the sharks. Photo courtesy of Andy Mann at http://www.andymann.com.

We had run out of satellite tags for the day. Lucy Howey of Microwave Telemetry, Inc., one of the project founders, was flying in that afternoon with more tags. One of the primary goals of the research expedition is to monitor the movements and behavior of the endangered oceanic whitetip shark. These sharks can migrate over long distances throughout their lifetime, often crossing international and political boundaries. Yet political and ecological boundaries don’t often overlap. Protection efforts in one country can be overshadowed by destructive fishing practices in another. Understanding shark migration patterns across borders is crucial to their overall protection.

Although the oceanic whitetip is endangered, Cat Island remains one of the best places in the North Atlantic where these sharks can be found. It is a unique place with a steep ocean drop off on its eastern side – and one of the few places where whiteips congregate close to shore. In order to study the shark’s movements, behavior, and breeding grounds, the team fits oceanic whitetips with special pop-off satellite archival tags (PSAT’s). The PSAT stays attached to the shark for about a year, at which time it pops off and transmits the recorded data to a satellite. To date the team has put out over 100 satellite tags, with about 1/3 being recaptures. This gives them valuable information about how the shark have grown, where they breed, and where they have pups, and leads to more targeted and effective management practices.

A shark was circling the boat. Mark Bond and Andy Mann were in the water filming a lone female oceanic whitetip. They hopped out of the water at one point because they thought she was being aggressive – coming in fast toward them and poking the camera, circling around and then heading at them again. But, after a few minutes, they splashed into the water again to give it another try. She had calmed down a bit, or they relaxed, or most likely a little of both. After watching Mark and Andy and the shark circle each other for about 15 minutes, I finally worked up the courage to get in myself. I was terrified. This is the first time I’ve been in the water with a big shark.

The cool blue water consumed me. I tried to stay close to the boat in case I had to hop out fast. I quickly took my bearings and looked around me: there was Andy, there was Mark, and there was the shark. She was 20 feet away, looking at me with curious eyes. She swam down deep for a minute and then circled back, continuing to watch us.

Earlier in the day, I had asked John, a NOAA researcher on the trip, what he like most about these sharks. He said, “Their curiosity.” I now understood what he meant.

She glided smoothly straight toward me. Her eyes, almost thoughtful, checking me out as much as I was checking her out. I looked at her head on. I couldn’t see her body, just her grey oval face and white chin. She was silhouetted by the deep blue sea. Strings of light filtered through the water like a comb and slowly dissipated, overtaken by the dark blue from hundreds of feet below. There was nothing around us: just blue.

Oceanic whitetip swimming into the deep blue. Photo credit: Andy Mann
Oceanic whitetip swimming into the deep blue. Photo credit: Andy Mann

This was not my world, it was hers. She was so graceful and sleek; her movements were effortless. As I clumsily fumbled in the water, she almost laughed with her beady eyes that she never took off of me. I waved my arms to push back as she came closer, her body seemed perfectly still, yet she moved faster and with more precision than I ever could. I pushed backward, behind Mark, who had a stick to gently push her away if she got uncomfortably close.

Christine O’Connell and Mark Bond in the water with an oceanic whitetip.
Christine O'Connell in the water with an oceanic whitetip.
Christine O’Connell and Mark Bond in the water with an oceanic whitetip.
Christine O’Connell and Mark Bond in the water with an oceanic whitetip.

Her approach entranced me: wide set eyes set apart on the edges of her face, jaw slightly agape, stretching straight across her face with the ends of her mouth curving down a bit, touting a somber grin. She had an emotionless, blank, and surprisingly deliberate look – the kind of look that for a second puts you at ease, calming. There was no feeling behind it, good or bad. It makes you let your guard down for a moment, tricking you into thinking she wouldn’t hurt you if given the chance. This is her lure – her effortless quiet swim, her blank stare, as if she is saving every bit of energy for the exact moment she needs it, for that split second she attacks. She is efficient, fierce, strong. Oceanic whitetips are able to survive and thrive out in the vast open ocean because they are agile hunters and artful scavengers. But for today, for right now, she is our friend. Though, I wonder what would happen if we met under different circumstances…

I realized through my encounter with her what magnificent animals these sharks are and the importance of protecting them. This amazing team of researchers is doing important work.