Thornback ray reintroduction in Dutch Zeeland


This video is called Thornback ray or thornback skate (Raja clavata).

Dutch daily Trouw reports today about thornback ray reintroduction in Dutch Zeeland province.

On Saturday 14 October 2017, five young thornback rays, raised in aquariums, will be brought to an oyster farm in Yerseke town. There, they will get used to the Oosterschelde estuary water. In a few weeks’ time, they will be freed. Later, more, up to 1000, young thornback rays will be freed. It is hoped that they will be a sustainable thornback ray population in the Oosterschelde; where they had become extinct. This species is sexually mature after eight years. Will they survive now? We don’t know yet.

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Sharks, rays live longer than estimated before


THis 2014 video from the USA says about itself:

Stingrays and Manta rays come in many shapes and sizes… But one of the coolest rays in all the ocean has to be the giant Shark Ray.

In the front they are broad like a ray, but the back section they are all shark with dual dorsal fins. How cool is that! Also known as a bowmouth guitarfish, this large species can reach a length of 2.7 m (8.9 ft) and weigh up to 135 kg (298 lb).

WHERE TO SEE RAY SHARKS IN THE USA In one of the biggest resorts in town, there’s a major Aquarium with full grown Shark Rays in it. It’s called the “Shark Reef” and it’s main tank is filled with 1.3 million gallons of water. This Aquarium displays all kinds of sharks, rays, fish, reptiles, even a green sawtooth shark — but the real celebrities here are the Shark Rays….

Just step inside what they call the Shark Tunnel and within seconds you will have a very up close and personal encounter – guaranteed!

SHARK RAYS ARE A THREATENED SPECIES Shark Rays are not dangerous to humans. They like to eat crabs or lobsters and stuff like that but their numbers in the wild are dwindling due to overfishing. They are killed for the shark fin on top. It’s the main ingredient in Shark Fin Soup which is popular in certain parts of the world. Attempts to breed these amazing creatures in captivity so far has been a failure. Seven pups born at the Newport Aquarium in Kentucky all died within a few months of their birth.

From James Cook University in Australia:

Sharks and rays live a lot longer than we thought

September 29, 2017

A James Cook University researcher has found that sharks and rays live a lot longer than we thought — some twice as long as previously estimated.

Dr Alastair Harry looked at 53 different populations of sharks and rays that scientists had already intensely studied. He said in nearly a third of populations the studies had underestimated the animals’ ages.

“Questions arose over methods of ageing sharks after it was found that grey nurse sharks can live up to 40-years-old, double the length of time first thought, and the age of New Zealand porbeagle sharks had been underestimated by an average of 22 years,” he said.

Dr Harry said scientists usually measure shark age by counting growth rings in their vertebrae. These measurements are confirmed by tagging animals and injecting them with a fluorescent marker or by measuring carbon accumulated in the animals from atmospheric testing of nuclear weapons in the 1950s.

“Age underestimation appears to happen because the growth rings cease to form or become unreliable beyond a certain size or age. Across the cases I studied age was underestimated by an average of 18 years, and up to 34 years in one instance. From the amount of evidence we now have it looks like the problem is systemic rather than just a few isolated cases,” he said.

Dr Harry said accurate age estimation was important because it was used to manage fishery stocks.

He said the underestimation of longevity in orange roughy, a deep-sea fish, led to overly optimistic estimates of stock productivity, contributing to serious, long-term ecological and socio-economic impacts.

Dr Harry said sharks and rays are less commonly targeted by commercial fishers, but are still often caught as bycatch. That means the impacts of age underestimation may well take longer to become apparent.

“It could lead to inefficient prioritisation of research, monitoring and management measures. If it’s as widespread and common as it seems from this study, the impacts could also be substantial from a wider scientific perspective, affecting the many disciplines that also use baseline life history data,” he said.

Stingrays on video


This video says about itself:

17 March 2017

Jonathan visits the world-famous “Stingray City” in Grand Cayman with world-renown marine artist Dr. Guy Harvey to learn about Dr. Harvey’s research on Stingrays and how they cope with massive numbers of tourists.

JONATHAN BIRD‘S BLUE WORLD is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

Manta ray video


This video says about itself:

Yap Manta Rays (HD) | JONATHAN BIRD’S BLUE WORLD

17 June 2016

Jonathan travels to the island of Yap in Micronesia to learn about and dive with the resident population of Reef Manta Rays! They have been photo identified and named.

Giant manta ray at play, video


This video, recorded off Peru, says about itself:

Curious giant manta ray surprises manta researcher! The manta researcher was collecting a photo ID, used to monitor population trends that can help identify the effects of fishing pressure on this population of manta rays.

Full story here.

See also here.

Peru Affords Full Protection to World’s Largest Known Manta Population: here.

4 things we’ve discovered from tagging Indonesia’s mantas: here.

Save Hawaii’s manta rays


This video says about itself:

GoPro: Diving With Manta Rays

23 August 2014

Chris Cilfone dives in the waters off Maui, Hawaii and encounters a school of Giant Oceanic Manta Rays.

From Wildlife Extra:

Protection sought for Hawaii’s manta rays

Manta rays in Hawaii are at risk of entanglement in fishing lines

Despite laws in Hawaii protecting manta rays from being killed or captured, one in 10 manta rays observed in the area of Olowalu suffers from an amputated or severely damaged cephalic fin, reports the Hawaii Association for Marine Education and Research (HAMER).

The cephalic fin is an important appendage used to guide water and plankton into their mouths when feeding and these injuries are caused by entanglement in fishing line.

When they encounter a line, most likely at night, they lock their cephalic fins together and begin to roll to try to get free, only wrapping themselves tighter into the line.

They eventually break free but over weeks and months the wrapped fishing line cuts into the flesh eventually removing the entire fin or rendering it useless.

HAMER is campaigning to stop entanglement by tagging mantas with acoustic pinger and satellite tags that can be tracked and identified to each individual manta.

By doing this it hopes to identify important habitats and understand how and where they overlap with fishing areas where there is a high risk of entanglement.

The organisation will make use of the University of Hawaii’s vast network of bottom mounted acoustic receivers dispersed throughout Maui County waters.

In addition to the acoustic tags, satellite tags can provide much greater fine-scale resolution of habitat use with instantaneous results on the animal’s location and dive profile.

Once these important habitats have been identified, HAMER can begin work to engage with local fishermen and gain their support to protect the mantas.

For more information and to offer support visit www.hamerhawaii.com and www.indiegogo.com/projects/save-maui-s-manta-rays.