Chasing Porbeagles - Story and Images

First published in DIVE Magazine September 2008

CHASING PORBEAGLES

Unlike its infamous cousin, the elusive Porbeagle poses very little threat to divers. In fact, if you are lucky enough to spot one while wandering over a reef, it is doubtful that you will have time to alert your dive buddies before the petrified predator disappears back into the depths. Not surprisingly, photographing a Porbeagle is no easy task.

They have good reason to fear humans. In the last few decades Porbeagle populations have been decimated by over-fishing and those that remain need to be protected.

On the Canadian side of the pond, Dr Steve Turnbull from the University of New Brunswick is conducting a tagging program to see if the Porbeagles in the Bay of Fundy are permanent residents or transients stopping by for a quick bite before swimming off to Europe. If it turns out that the sharks are residents, then any further shark fishing in the bay will quickly deplete the local population.

Intrigued by the idea of watching a diver jump into the Bay of Fundy’s racing currents, Steve agreed to let me accompany him on a tagging trip. The bay is notorious for its seven metre plus tidal exchanges which create currents strong enough to tear the mask off any diver foolish enough to venture in for a quick dip. Add to this the many tonnes of mud that the tides suck out to sea each day and your odds of getting a good look at a Porbeagle are pretty slim.

I met up with Steve’s team in Alma, New Brunswick aboard a lobster fishing boat ominously named the Storm Cloud. As dawn spilled over the North Atlantic we outpaced the receding tide to the middle of the channel and started laying out a chum slick to entice in the sharks.

While we waited, Steve told me a little about Porbeagles.

They are born at around seventy centimetres, but when fully grown they can exceed three metres, and some may get closer to four.

Porbeagles belong to the mackerel shark family which also includes Longfin and Shortfin Makos, Salmon Sharks and Great Whites.

Mackerel sharks possess a unique web of thin walled blood vessels called a rete mirablé. The reté transfers heat generated in the muscles to colder blood coming from the gills which effectively elevates the shark’s body temperature. The pay off is increased speed and mental agility that give mackerel sharks the edge they need over their fast moving prey.

The Porbeagle’s closest relative is the Salmon Shark which lives on the Pacific coast of North America. Salmon Sharks lack the distinctive white spot that Porbeagles have on the trailing edge of their dorsal fins. They also have a second caudal keel (lateral protrusions in front of the tail) below the main one to increase their stability.

As well as the North Atlantic Porbeagle population there are isolated groups clustered around southern Africa, Australia and South America. They are found from the surface down to around 700 metres.

As I digested this information I kept one eye on the bobbing hang bait. When it suddenly disappeared underwater the dozing crew sprang into action.

A Porbeagle surfaced close to the boat thrashing on the baited line, then dove again and headed away at full speed. Sealing my drysuit, I sprang two metres from the deck of the tossing fishing boat and turned to catch my camera housing.

The current instantly grabbed me and I kicked furiously to stay in position while a tag line was prepared. Once I had something to hold onto, I sank under the pounding waves to look for the shark. The water was the colour of green detergent occasionally punctuated by the Porbeagle’s white belly as it zigzagged back and forth under the boat.

Slowly the shark tired. It eyed me warily but gave very little resistance as the crew guided it into a cradle and hoisted it out of the water.

Steve’s team quickly completed their measurements and inserted the tag that they hoped would eventually supply the information they needed. Before long, a shout from above warned me that the Porbeagle - now freed from its line - was about to be released.

I dragged my housing into position and squinted through the viewfinder. For a while all I could see was green fog. Then, in a cloud of bubbles the Porbeagle splashed into view and swam straight at me.

Realising that this would probably be my only chance, I fired shot after shot, barely waiting for my strobes to recycle. The shark’s enormous black eye kept me in sight as it circled briefly, then flicked away into the darkness.

I floated in the gloom watching its retreat, captivated by the image of its heavy set, slate grey body and penetrating gaze.

A tug on the rope brought me around and I over-armed against the relentless current towards a makeshift ladder that the crew had lowered. It wasn’t until I was back onboard that I was able to review my images and I was relieved to find the face of the Porbeagle staring back at me. It was a frustratingly short encounter but one that I will never forget.

You can do your bit to save the Porbeagle and Britain’s other endangered sharks by joining the Shark Trust at www.sharktrust.org.

Porbeagle Shark Images

 

Porbeagle Shark 018	Porbeagle Shark 005	Porbeagle Shark 003	Porbeagle Shark 002	Porbeagle Shark 025
Porbeagle Shark 022	Porbeagle Shark 030

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