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News of Sharks

FEBRUARY 2013

Feb. 23 , 2013 - 3,500 lbs Great White Shark getting a Little too close.


The most exciting piece of fishy news this week has almost nothing to do with local angling and everything due to sensationalism. Sadly, it should be rated up their with the National Geographic Channel or Animal World as it involves cutting edge research but, for most people, the word “shark” and especially “great white shark” evokes completely different feelings.

After having travelled thousands of miles up and down the American East Coast in a relatively short five months, a report that the almost 3,500 pound behemoth has been tracked electronically to within a few miles (in the ocean, even a 100 miles isn’t a lot) of Bermuda has put a lot of local potential skinny dippers off taking the plunge. It isn’t just the chilly water temperature but the fear of being a shark’s supper that is keeping people out of the water.

It is funny how a bit of information can cause a stir. Has it occurred to anyone that Mary Lee may well be on her way here to join 1,000 of her friends and family or to take part in some sort of feeding frenzy? The latter is unlikely to include Homo sapiens, given the incidence of shark attacks of any sort around here. Just inject the thought of a bit of night swimming and there you have it, mad panic — many thanks, Peter Benchley!

Do those same people ever think that great whites have occurred here before and been properly documented by those who know about such things? Not to mention the many other shark species that normally occur here that have earned the moniker “man-eater” elsewhere in the world. Include the familiar tiger shark and the less commonly seen but nonetheless present oceanic white-tip shark as species that have earned that title.

What this area does lack are the huge schools of oily baitfish that are the preferred dining venues for giant tunas and the sharks that often travel in their wake, picking up the pieces. Something that some may not have noticed is that the spring wahoo run (anytime form late April until early June) often brings with it some mako shark activity. There are plenty of stories of half wahoo being reeled in or specimens that have pretty well been shredded during the process of their capture.

There is no reason why makos don’t effect similar movements for similar reasons that great whites make their migrations. Having said that, water temperature may have something to do with things as well. Makos are thought to be more tropical than great whites but who isn’t to say that Mary Lee may have gotten into an eddy of water at a favourable temperature and just be staying within its confines even though it is moving toward Bermuda.

To look at some of the more positive outcomes of this story: this is one of the few instances where a specimen of a large, relatively rare species has been tracked reliably over enough time. Although the data is excellent, it really goes to show just how much more is needed before any definite conclusions can be drawn. The same goes for marlin and tuna research. A huge amount of data is needed to even start to fathom out the mysterious world of oceanic apex predators.

The other item which is of obvious angling interest was the local capture of a swordfish that dressed out at around 110 pounds. The catch was made by a well-known commercial fisherman who has always been willing to experiment with new and different tactics. One of these is the night-time trolling for swordfish that has become popular in Florida and elsewhere.

For some time now, drift fishing at night has been the means by which swordfish were caught by sportsmen.

It has been attempted here with some success but never really caught on. Local anglers are pretty set in their ways and it is the daylight fishing for wahoo, tuna and marlin that is the norm and certainly is the basis for tournament fishing.

The new trolling technique, probably developed by an insomniac, is advantageous in that it allows fishing to be conducted while travelling to and from the fishing grounds (remember that off the US it is often a long run to the deep blue water and some boats do leave at night in order to be offshore at daybreak) and because the trolling speed is slow, it is easier on the fuel bill.

It is not as if it wasn’t known that swordfish inhabit local waters. In fact, there aren’t too many places where there is not a fishery for swordfish and in some places these fisheries are, literally, ancient.

Swordfishing in the Mediterranean goes back an awfully long way having been mentioned in early literature before the time of Christ. There is little doubt that fishing for swords was going on long before anyone decided to write anything about them, so “ancient” is probably an apt description of the Mediterranean fishery for this species.

So long has the Mediterranean fishery gone on, that there are some who accept that the species in that sea is, in fact, separate to that found everywhere else. The fish are smaller versions of the oceanic swordfish and there is evidence that they mature earlier.

This would be consistent with the pressure put on the species by thousands of years of exploitation by man in a relatively small body of water. Entire fleets of boats have been developed for the swordfish harpoon fishery which continues to be one of the main ways in which swords are caught.

In any case, there is a worldwide fishery for swordfish which are found in all the major oceans. Ever-increasing demand has led to some international controls on effort and landings; but, as is usually the case, the net effect of such regulation leaves a lot to be desired. Given that the total Bermuda catch pales into insignificance on the world stage and the remote likelihood that any form of angling for this species is going to catch on to any great length, landings of swordfish are likely to remain at the incidental level.

With the first real signs of spring just starting to emerge, it will be some time yet before sport fishing again comes into its own. There are a few unconventional aspects of fishing that one might be able to indulge in and, naturally, there was the usual wise guy who suggested that an effort should be made to catch Mary Lee. Any such action would undoubtedly be frowned upon by a good many even though it would more than certainly provide some exciting and immensely Tight lines!

 

 

 

 

Feb. 22 , 2013 - Indonesia has announced a new shark and manta ray sanctuary, the first to protect the species in the rich marine ecosystem of the Coral Triangle, known as the "Amazon of the ocean".

Environmentalists Wednesday welcomed the creation of the 46,000-square-kilometre (18,000-square-mile) protection zone, in an area at risk from both overfishing and climate change.

The local government in Raja Ampat on the western tip of New Guinea island announced the move this week, issuing local regulations to ban the finning and fishing of sharks in the area, a tourist destination popular with divers.

Rizal Algamar, Indonesia director of the Nature Conservancy, described the regulations in a joint statement with Conservation International as a "breakthrough in policy".

"Scientific evidence states that the value of live sharks and manta rays far outweighs the one-time profit of dead sharks and manta rays, benefiting a growing world-class and increasingly popular marine tourism and dive destination," he said.

Scientists have warned the Coral Triangle, which spreads across a vast area of Southeast Asia's waters, is under threat, with heat-trapping carbon gases blamed for creating acidic seas hostile to much marine life.

Overfishing has also been a problem, but the sanctuary will support existing no-take zones that have helped shark numbers slowly recover.

"Sharks in particular play an important role, as apex predators at the top of the food chain, maintaining fisheries and ecosystem health," the statement said.

The sanctuary is also expected to prevent a drop in manta ray numbers, with the species' gills increasingly used in Asian medicines.

Shark populations are in a rapid and steep decline worldwide, facing intense pressure from fishing and in high demand for shark fin soup.

Up to 73 million sharks are killed annually, mostly for their fins, the statement said. As a result, many shark species have suffered declines greater than 75 percent and in some species up to 90 percent or more.

Indonesia ranks as the world's largest exporter of sharks and rays.

 

 

 

 

 

Feb. 21 , 2013 - A glow-in-the-dark shark scares off predators with "lightsaber-like" spines on its back, a study suggests.
 


The research was carried out on the velvet belly lanternshark, a small species found in the deep waters of the Atlantic Ocean and Mediterranean Sea.

The scientists believe that while the light-up spines can be seen by larger, potentially dangerous fish, they are harder for the shark's prey to spot.

The study is published in the Nature journal Scientific Reports.

Invisibility cloak

This species of lanternshark (Etmopterus spinax) lives in the mesopelagic zone of the ocean, which has a range between 200m and 1,000m in depth.

It is a diminutive shark; the largest can measure up to about 60cm in length, but most are about 45cm long.

Until recently, little had been known about this species, apart from the fact that like many deep sea creatures it has the ability to glow - a trait called bioluminescence.

Previous research found that the shark has light-producing cells called photophores in its belly, and it uses this light to camouflage itself.

"Imagine you are below the shark, the shark is swimming and you have the light from the Sun coming down," explained Dr Julien Claes, a shark biologist from the Catholic University of Louvain in Belgium, and the lead author of the study.

"If you are just below the shark what you are going to see is a shadow. So imagine if the shark can actually produce a light, which is identical to the light produced by the Sun. Then the shadow of the shark is going to disappear."

Any prey lurking below, typically a small fish called Mueller's pearlside, will not see the shark coming.

However, this new study revealed that the shark is also luminescent on its top side.

Dr Claes said: "There are two spines, one in front of each dorsal fin, and just behind them you have two rows of photophores. They are like lightsabers - they illuminate the spine.

"It was surprising - why would you try to be invisible from below but visible from the dorsal side?"

Warning beacon

Visual modelling experiments revealed that potential predators could see the light from several metres away.

The shark's prey, however, could only see the glow from a distance of about 1.5m, giving them less chance of making an escape.

The team concluded that the glowing spines were acting as a beacon, illuminating the shark's threatening spines.

Dr Claes: "It's a way to say: 'Don't bite me, I'm dangerous, I have spines on my back. You could be hurt.'

"When you live in this dark place, what you try to do is avoid is to be seen by other animals, because there are no places to hide.

"It can be very dangerous - you put yourself at risk when you produce light from your back, unless it acts as a warning system."

He said it was unusual to find an animal that was using light to both hide and advertise itself at the same time.

"It's surprising that these two apparently opposite behaviours can occur in a single organism at the same time. It is really paradoxical."

 

 

 

 

SHARK NEWS ARCHIVES
( As of December 2012 )

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