Shark sanctuary in Madagascar


This video says about itself:

Indian Ocean shark footage – Raw

11 June 2012

Here are 2 minutes of pure shark watching. Take a look as some beautiful marine life responds to researchers luring them with a bag of chum in the Indian Ocean.

From the Wildlife Conservation Society:

Madagascar Creates Shark Park

February 4, 2015

Great news bite: the government of Madagascar has created the country’s first shark sanctuary in Antongil Bay to protect 19 shark species! The law that creates the sanctuary also grants local communities exclusive use and management rights to fishing areas.

WCS is committed to protecting the incredible biodiversity of Madagascar, as well as sharks. Of the 19 species protected by this sanctuary, one third have become severly threatened by unregulated fishing.

“With the support from Wildlife Conservation Society, we chose a participatory and collaborative approach for the development of this law and management plan and we opted for the search for a balance between fishing activities and ecological integrity to ensure rational and sustainable exploitation of fisheries resources” said Mr. Ahmad, Minister of Marine Resources and Fisheries at the press conference in Antananarivo.

White sharks grow more slowly than thought


This video is called White Shark Cage Diving – Mossel Bay, South Africa.

From NOAA Headquarters in the USA:

February 18, 2015

White sharks grow more slowly and mature much later than previously thought

6 minutes ago

A new study on white sharks in the western North Atlantic indicates they grow more slowly and mature much later than previously thought.

The findings, published online in Marine and Freshwater Research, present the first reliable growth curve for this species in the western North Atlantic. The results: males are sexually mature around age 26 and females around age 33, much later than currently accepted estimates of 4 to 10 years for males and 7-13 years for females.

“Using the longevity data obtained from our first study, we are now able to describe not just how long white sharks live, but also the growth rate for this species, which is remarkably slower than anybody thought,” said Lisa Natanson, a fisheries biologist and shark researcher at NOAA’s Northeast Fisheries Science Center and lead author of the study.

To construct the growth curve, researchers combined recently published information on white shark longevity with a further look at band pair counting on vertebral samples from 77 white sharks (Carcharodon carcharias), 41 male and 36 female. Band pairs, counted like tree rings, are alternating opaque and translucent deposits laid in sequence in shark vertebrae as the animal grows. Since the deposition rate may change over time, researchers must determine or validate the actual rate that the bands are deposited.

The research on longevity demonstrated that band pair counts were reliable up to 44 years of age, after which band pair counts underestimated ages that could exceed 73 years. The estimated age at maturity reported here could lead to new estimates of population replacement rates that are much slower than those used in the past.

Natanson and co-author Gregory Skomal of the Massachusetts Division of Marine Fisheries examined the banding patterns on vertebrae from white sharks collected between 1963 and 2010 by the NOAA Fisheries Apex Predators Program. These samples came from white sharks caught on research cruises, taken by commercial and recreational fishing vessels, or landed at recreational fishing tournaments. Sampling took place between Prince Edward Island, Canada, and New Jersey.

The distribution of white sharks in the western North Atlantic is well documented, although the species is considered rare and much of what we know about it comes from distribution records, a handful of observations, and dead specimens.

This study adds to other recent publications about white sharks. For example, a 2014 study used records compiled over 200 years, from 1800 to 2010, to look at the seasonal distribution and historic trends in abundance of white sharks in the western North Atlantic Ocean.

Increased numbers of white sharks off Cape Cod in recent years has provided Skomal and others with opportunities for satellite tagging, another way information is being gathered on shark movements. However, scientists still know little about the natural history of this species, including its reproductive biology and feeding ecology.

Sharks are slow-growing, long-lived animals with low reproduction rates. They are fished commercially throughout the world. Wise conservation requires life history information, including age and growth data, for sustainable management. While vertebral band-pair counts can provide age estimates for many species of sharks, it is critically important to validate how often the band pairs are formed in order to obtain accurate age estimates.

The shark vertebral samples for this study were provided by Natanson from the Apex Predators Program, which maintains one of the largest collections of North Atlantic white shark vertebrae. The Apex Predators Program, located at the NEFSC’s Narragansett Laboratory in Rhode Island, collects basic demographic information about sharks and their life histories by conducting research on their distribution and migration patterns, age and growth, reproductive biology, and feeding ecology.

With lifespan estimates of 70 years and more, white sharks may be among the longest-lived fishes. Sharks that mature late, have long life spans and produce small litters have the lowest population growth rates and the longest generation times. Increased age at maturity would make white sharks more sensitive to fishing pressure than previously thought, given the longer time needed to rebuild white shark populations.

Tiger sharks make long migrations, dive deep into cold waters: here.

Rare megamouth shark beaches in the Philippines


This video is called Alien Sharks: The Megamouth.

By Cheryl Eddy, 29 January 2015:

Incredibly Rare And Mysterious Deep-Sea Megamouth Shark Washes Ashore

There have been fewer than 100 confirmed sightings of the megamouth shark, an elusive deep-sea species that uses its huge maw to trap tiny bits of plankton and krill. So when a 15-foot specimen washed ashore in the Philippines this week, scientists were more than overjoyed.

Pro-shark pioneer diver Lotte Hass dies


This video is called Lotte Hass snorkeling, vintage film.

From Wildlife Extra:

Lotte Hass, one of the world’s first female divers, has died

The Hans Hass Institute in Germany recently announced the death of Lotte Hass, one of the world’s first female scuba divers.

She passed away at the age of 86 on Wednesday, 14th January 2015 after a happy and multi-faceted life.

The first woman to dive with autonomous diving equipment, Lotte Hass entered a formerly male dominated field in 1949 and opened up a whole new world for women.

Against strong opposition she first starred as underwater photo model before moving behind the camera to become an underwater photographer.

Spectacular scenes that showed her diving with sharks certainly contributed to the success of her husband Hans Hass’ films in the 1950s, and a greater understanding of sharks with the public.

The importance of her extraordinary lifetime achievements were highlighted by the 2011 screen adaption of her autobiography A Girl on the Ocean Floor.

The Institute has asked those who want to acknowledge the accomplishments of Lotte Hass as a diving pioneer to support SHARKPROJECT, an organisation that is dedicated to preventing the destruction of the oceans and the extinction of sharks.

Biology of the megamouth shark


This video is about megamouth sharks.

By Kazuhiro Nakaya in Japan:

Biology of the Megamouth Shark, Megachasma pelagios (Lamniformes: Megachasmidae)

Graduate School of Fisheries Sciences, Hokkaido University 3-1-1, Minato-cho, Hakodate, Hokkaido 041-8611, Japan

Abstract

All records to date (end of June, 2008) of the megamouth shark, Megachasma pelagios were analyzed and the biology of the megamouth shark was inferred from them. The megamouth shark is a wide-ranging species, distributed from the tropical to temperate seas, with the most numerous occurrences in the western North Pacific Ocean. Young individuals tend to be distributed in warmer waters, while mature individuals broaden their habitat to higher latitudes. Males become mature at about 4 m in total length and females at about 5 m. The megamouth shark may copulate all year round, giving birth to young
in warmer waters, and may be spatially segregated by sex.

The discovery of the megamouth shark was one of the ichthyological highlights of the last century.

The first specimen of the megamouth shark was accidentally collected in Hawaii in 1976, and the species was eventually named Megachasma pelagios by Taylor, Compagno and Struhsaker (1983). The second specimen was captured in 1984 in California, U.S.A., eight years after the capture of the first Hawaiian specimen (Lavenberg and Seigel, 1985). The third specimen was found stranded in 1988 off western Australia in the Indian Ocean (Berra and Hutchins, 1990). Then, the fourth and fifth specimens were reported from Japan in 1989 (Nakaya, 1989; Miya et al., 1992). The sixth specimen was captured and released in California with a sonic transmitter (Lavenberg, 1991), and its horizontal and vertical movements were recorded for a few days (Nelson et al., 1997). These specimens were all giant males of about five meters in total length, except for the fifth one of unknown sex, and finally the first female megamouth was caught in Japan in 1994 (Takada et al., 1997).

At present, the worldwide total of megamouth shark captured, found stranded or sighted is forty specimens. Some of the specimens were studied for their morphology and phylogenetic relationships, but most of them were discarded, consumed or not studied. Among the few studies available, Nelson et al. (1997) reported part of their way of life, showing that the megamouth shark makes clear daily vertical movements within depths shallower than 200 meters. However, most of the biology of the megamouth shark still remains to be disclosed.

The purposes of the present study are to synthesize the scattered information of the 40 specimens recorded as of June, 2008, to study the morphological and biological evidence of each specimen, to analyze their capture data, and to discuss the biology of the megamouth shark.

Australian sharks feed on dead humpback whale


This video from Australia says about itself:

Tiger Shark Feeding Frenzy – The Death of a Humpback Whale

25 May 2014

When an organism as large as a humpback whale dies in an ocean system, who cleans up that big rotting mess…. We know! Apex predators like the tiger shark are renowned scavengers. This is a collection of footage showing the 3 day process of what happened in Coral Bay when a humpback whale died and washed over the reef.

From the Australian Broadcasting Corporation:

Beaches closed as sharks feed on whale carcass near shoreline on NSW South Coast

By Tegan Osborne

Updated about 7 hours ago

Sharks have been seen devouring a dead whale floating close to rocky coastline at South Broulee near Batemans Bay in NSW, forcing authorities to close five beaches.

The young humpback whale was spotted off the rocks at the popular swimming beach on Wednesday morning, according to Stan Wall from Lifeguard Services Australia.

A 100m exclusion zone was set up around the whale and at one point a crowd of more than 300 people gathered to watch.

However, Mr Wall said, after some time, lifeguards in the area were unable to see any spray or air bubbles coming from the animal and it was presumed dead.

“We think it might have come into collision with a boat or maybe even hurt itself on the rocks that we saw it on this morning,” Mr Wall said.

Clear signs the animal was seriously ill: ORRCA

Shona Lorigan, from the Organisation for the Rescue and Research of Cetaceans in Australia (ORRCA), said once the animal died, a group of sharks moved in and began devouring the carcass.

“The sharks are dangerous and are in a feeding frenzy so it’s important that everyone stays away,” she said.

“It’s very important for their own safety – don’t go near a dead animal, particularly one that showed signs of ser[i]ous illness.”

She said the whale was seriously underweight and was infested with large numbers of whale lice.

“There really is very clear evidence that the whale itself was sick before it passed away,” she said.

Ms Lorigan said four members of ORRCA went straight to the beach after calls from the public.

“We got a large number of calls from the beach this afternoon, and that immediately activated our rescue team,” she said.

“While they were in transit… we were on the phone with members of the public advising them on the situation, and we became aware that the animal had passed away.”

Beaches remain closed until further notice

Mr Wall said Shark Bay, North Broulee, South Broulee, North Head and Moruya beaches would remain closed until further notice.

He said lifesavers had met with Eurobodalla Shire Council and would do so again early on Thursday morning to re-assess what, if anything, should be done with the carcass.

“We’re hoping with the change in tides it actually might get washed out [to sea],” Mr Wall said.

A Westpac Lifesaver helicopter was deployed on Wednesday afternoon to help ensure the area had been cleared of people, he said.

15-million-year-old snaggletooth shark discovery in Maryland, USA


This video from the USA says about itself:

7 November 2014

Snaggletooth Shark Skeleton quarried in Chesapeake Beach on Halloween. Found by the Gibson family in their back yard.
This is the first articulated snaggletooth shark from Calvert Cliffs, if not the world.

From Associated Press today:

Md. family uncovers 15-million-year-old skeleton during dig

JULIE ZAUZMER | Updated 22 hours ago

SOLOMONS, Md. (AP) — Donald Gibson found the first vertebra Oct. 23, just as he had begun to dig out the space for the sunroom he had promised to build in the back yard of his parents’ home in Calvert County.

Over the following week, his brother, Shawn, found another vertebra, and then another, and then a few more — each one about 18 inches deep into the ground. Soon, Shawn Gibson’s 7-year-old, Caleb, joined in on the digging. He’s at an age of being “thrilled to go out and not just play in the dirt, but actually find pieces,” Gibson said of his son.

After all, it’s not that unusual to dig up fossils in the Calvert Cliffs neighborhood. But then they found something more: a straight column of vertebrae, two feet long. And at the end, a tooth.

The digging stopped.

What the Gibsons unearthed were the remains of a 15-million-year-old snaggletooth shark, which paleontologists say is more complete than any other fossil of its kind in the world.

Stephen Godfrey, curator of paleontology for the Calvert Marine Museum, said that the Gibsons’ discovery is so unusual because of the number of bones they found — more than 80 vertebrae and hundreds of teeth, all from the same shark — as well as the position they were in and their unusually good preservation.

In fact, the discovery is so rare that when Shawn Gibson called museum officials and asked them to come out immediately — on Halloween night — Godfrey said he had his doubts.

The description Gibson provided — of a complete snaggletooth shark skeleton, including the spine and the skull cavity — seemed so outlandish to Godfrey that he could scarcely believe it.

But he and John Nance, an assistant curator, were intrigued enough to hop in the car right away.

“While we’re driving up there, I’m thinking to myself, ‘This can’t be an actual fossil of a shark,'” Godfrey said. “But it couldn’t be a horse or a cow. It had to be a shark.”

Once he laid eyes on it, he had no doubt.

“It was immediately obvious,” he said. “It was a genuine article.”

The Gibsons showed him about 50 vertebrae they had unearthed, and Godfrey was grateful that they had stopped digging once they reached the teeth. Godfrey and Nance wrapped the entire skull cavity in a stiff plaster cast, like one used to set a broken bone.

Sharks’ skulls are made mostly of cartilage, not bone, so they almost never withstand the ravages of time, Godfrey said. Yet somehow, the shark that came to rest in the Gibsons’ backyard sank belly-up when it died during the Miocene Epoch. It became buried in sand, then by sediment eroding from the Appalachian Mountains. And its skull cavity — containing hundreds of the distinctively shaped teeth, up to an inch-and-a-half long, that give the snaggletooth its name — kept its shape.

Using a microscope, the scientists digging in the Gibsons’ yard were able to see the distinctive hexagonal shape of shark cartilage, fossilized and preserved.

Donald Gibson said he had pulled vertebrae out of the ground, one by one in a straight line, just as they were positioned in the back of the shark, which Godfrey said was 8 to 10 feet long during its life.

Having preserved the teeth and surrounding remnants of cartilage in exactly the positions they were found in, the paleontologists will be able to take CT scans of the cast and analyze the specific three-dimensional layout of the prehistoric shark‘s mouth, something scientists have never done.

“For the first time, we’re going to be able to know what the dentition — what the teeth — looked like in this kind of shark,” Godfrey said.

Then they will remove the cast, gently clean each piece and put the discovery on exhibit.

Shawn Gibson said that his parents had lent the fossil to the museum but might bring it home eventually.

“Obviously, we wanted to make sure it was able to be studied,” he said. “We wanted to make sure that the historical significance was documented and the specimen’s there to be studied. But it came from the yard, and it was a family affair. ”

There’s also the issue of the value of the fossil. Shawn Gibson said he doesn’t know what the shark might be worth.

“There’s obviously not a Blue Book for shark fossils and certainly not a one-of-a-kind find,” he said.

Godfrey said he is receiving emails from paleontologists up and down the East Coast who are excited about the discovery.

The skeleton will allow scientists to compare the prehistoric snaggletooth, an extinct species, and modern snaggletooths, a descendant species that lives in the Pacific.

Comparing the teeth of snaggletooths then and now will help scientists understand the workings of shark evolution, the likely diet of prehistoric species and the climate during the Miocene Epoch.

And the fact that the spine and the skull cavity of the shark found by the Gibsons are definitively associated with each other, the most complete snaggletooth skeleton ever found will allow scientists to identify whether smaller pieces of future fossils come from snaggletooths or other species.

“When in the future we find just a single vertebra, we’ll be able to say, ‘This comes from that kind of shark.’ And only because we have this association being made,” Godfrey said. “It’s just incredibly unlikely that we would make this kind of discovery.”

As for the Gibsons, the family now has a new hobby. While the sunroom goes up in the backyard, they have continued to dig. Caleb has found less-valuable bits of four more shark species.

“He had the day off of school for Election Day. I told him we could go fishing,” Shawn Gibson said. “He said, ‘I’d like to go look for shark’s teeth.'”