Commercial, recreational and party/charter boat fishermen from Maine to North Carolina have all rallied together to deal with an out-of-balance population of predatory spiny dogfish sharks that threatens the recovery of New England groundfish and several others fish stocks living along the U.S. East Coast.

The newly formed Fishermen Organized for Rational Dogfish Management (FORDM) has requested the assistance of Dr. Jane Lubchenco, newly appointed National Oceanic and Atmospheric Administration head, in dealing with the predator.

Spiny dogfish

The disproportionate abundance of dogfish is not a new problem; as early as 1992 Dr. Steven Murawski, now chief scientist of the National Marine Fisheries Service’s, wrote “Given the current high abundance of skates and dogfish, it may not be possible to increase gadoid (cod and haddock) and flounder abundance without ‘extracting’ some of the current standing stock.”

That was over 15 years ago and the situation has not improved. On the contrary, the amount of dogfish now exceeds that of skates, and dogfish comprises over half of all fish taken in the annual trawl surveys carried out by the Northeast Fisheries Science Center.

The spiny dogfish can exceed 150 cm in length and preys on virtually all species of fish smaller than itself. Dogfishes can also create a problem for other species by competing with them for prey fish.

This remarkable abundance of dogfish is most likely the result of countless years of ever increasing over-fishing. Spiny dogfish is not an appreciated food fish and the depletion of other species seems to have favoured it greatly in these waters.

The remains of a 15 meter[1] long sea living predator has been found in Svalbard, an archipelago located about midway between mainland Norway and the North Pole. The animal, a species of pliosaur dubbed Predator X by the group of scientists who discovered it, lived in the ocean 147 million years ago during the Jurassic period.

Predator X hunting (Photo: Atlantic Productions)

The skull of Predator X is twice as big as the skull of a Tyrannosaurus Rex and researchers believe the jaws of this hunter could exert a pressure of 15 tonnes[2]. The weight of the live animal is estimated to be around 45 tonnes[3].

“It is the largest sea dwelling animal ever found and as far as we know it is an entirely new species”, says palaeontologist Espen Madsen Knutsen[4] from the Olso University in Norway to Swedish newspaper Dagens Nyheter.

Knutsen is a part of the research team who dug out the skull and backbone of the creature during a two week long research expedition to Svalbard in June 2008. The remains were first discovered by Professor Jörn Hurum[5] from the Natural History Museum at Oslo University in 2007. Hurum noticed a piece of bone sticking up from the permafrost, but since it was the last day of the 2007 expedition the group was forced to leave the bone behind without any further investigation after having jotted down its GPS position.

Parts of the head and backbone was dug out during the abovementioned June 2008 expedition and together with an earlier find of a smaller specimen of the same species located just a few kilometres away, scientists have now managed to map together a good picture of what the live animal once looked like.

“We haven’t unearthed a high number of parts yet, but the parts that we do have are important ones and this has made it possible for us to create an image of what Predator X once looked like”, says Knutsen.

The digg site (Photo: Atlantic Productions)

In the excavated area, palaeontologist have found roughly 20,000 bone fragments – the remains of at least 40 different sea dwelling Jurassic animals. Once you’ve started digging in this region, it is fairly easy to spot the bones since their pale colour contrasts sharply against the black earth of the Svalbard tundra. The main difficulty is instead the short dig period and the fact that much time is spent restoring the excavated area after each dig.

“Each time we leave a dig site we have to restore the area. There can be no traces of our activities. This forces us to use half of our time digging up the same spot all over again when we return”, Kutsen explains.

Svalbard lies far north of the Arctic Circle and the average summer temperature is no more than 5°C (41°F), while the average winter temperature is a freezing −12 °C (10 °F). In Longyearbyen, the largest Svalbard settlement, the polar night lasts from October 26 to February 15. From November 12 to the end of January there is civil polar night, a continuous period without any twilight bright enough to permit outdoor activities without artificial light.

The team plans to return to Svalbard this summer to carry out more digging. They hope to find another specimen in order to make the skeleton more complete, and they also wish to unearth the remains of other animals that inhabited Svalbard at the same time as Predator X.

If you wish to learn more, you can look forward to the documentary shot by Atlantic Productions during the Svalbard excavations. The name of the documentary will be Predator X and the animal is actually named after the film, not the other way around. The film will be screened on History in the USA in May, Britain, Norway and across Europe later this year and distributed by BBC Worldwide.

Pliosaur crushing down on Plesiosaur with 33,000lb bite force (Ill.: Atlantic Productions)

All the scientific results will be published in a full scientific paper later this year.

You can find more Predator X information (in English) at the Natural History Museum, University of Oslo: http://www.nhm.uio.no/pliosaurus/english/

A research group[1] studying the hunting ability of the great white shark has found evidence indicating that this notorious predator actually has a fairly weak bite. In several movies – including the legendary Spielberg film “Jaws” – the great white shark has been portrayed as a hunter blessed with an exceptionally strong bite, but the allegedly fierce jaw power of Carcharodon carcharias is now being questioned.

According to research leader Dr Daniel Huber of the University of Tampa in Florida, sharks actually have very weak jaws for their size and can bite through their prey mainly thanks to their extremely sharp teeth – and because they can grow to be so large.

Photo by Terry Goss, copyright 2006

“Pound for pound, sharks don’t bite all that hard,” says Dr Huber. Compared to mammals, sharks have amazingly weak bites for their size. Lions and tigers are for instance equipped with much more jaw strength than sharks when you account for body size. According to Huber, mammals have evolved much more efficient jaw muscles.

During the study, Dr Huber and his team studied 10 different shark species. The bites of small sharks were fairly easy to measure, while large sharks had to be knocked out and subjected to mild electricity in order to stimulate their jaw muscles.

As mentioned above, sharks don’t really need strong jaws since they can grow so large and are fitted with extraordinarily sharp teeth. In addition to this, they also benefit from having very wide jaws. When they tear an animal apart, they frequently use a sawing motion.

Dr Huber hopes that their study will lead to the development of protective swim wear and other types of shark-proofing gear.

If you wish to read more, you can find the study “Is Extreme Bite Performance Associated with Extreme Morphologies in Sharks?” in the journal Physiological and Biochemical Zoology.

http://www.journals.uchicago.edu/doi/abs/10.1086/588177?prevSearch=(shark)+AND+[journal%3A+pbz]

Last Friday, 53 year old Florida Keys resident Greg LeNoir saved his dog Jake from being devoured by a shark by jumping into the water and punching the predator.

The incident happened when LeNoir and Jake visited the Worldwide Sportsman’s Bayside Marina pier in Islamorada and Jake jumped into the water for his daily swim. According to LeNoir, Jake is a fast and fearless swimmer who loves to retrieve soaked coconuts and jellyfish. But this day, the playful swimming session took a turn for the worse when a five-foot (1.5 m) long shark showed up and chomped its teeth into the 14-pound (6.3 kg) rat terrier.

As LeNoir watched his dog suddenly disappear under the surface, he didn’t hesitate to come to his rescue. ”I clenched my fists and dove straight in with all my strength, like a battering ram,” says LeNoir. ”I hit the back of the shark’s neck. It was like hitting concrete.”

While being pounded by LeNoir, the shark decided to let go of Jake, who frantically swam back to the shore, leaving a red trail of blood behind him in the water. Jake was rushed to the VCA Upper Keys Animal Hospital in Islamorada, where his wounds were attended by veterinarian Suzanne Sigel and emergency on-call assistant Callie Cottrell. The sharp teeth of the shark had punctured Jake’s skin and some muscle, and skin was hanging like ribbons from his right side and front left leg, but he wasn’t in critical condition.

”He looks great and is recuperating well,” Sigel said on Monday. ”I was worried he may have inhaled salt water when he was pulled under, but there’s no evidence of infection or pneumonia.”

The hungry shark has not been identified, but LeNoir believes it to be a bull shark or lemon shark. Sharks are not uncommon in these waters, partly because the Islamorada Fish Company has an open saltwater pool which attracts large tarpon – a yummy treat for many species of shark.