A satellite-tagged great white shark called Lydia is about to make history as the first of its species to be seen crossing from one side of the Atlantic to the other. Lydia was first tagged off Florida as part of the Ocearch scientific project. She is currently swimming above the mid-Atlantic ridge in the center of the Atlantic…
Fire in the Sea, published by Texas A&M University Press
This shark species, shown at right with a squid in its jaws, is rarely found outside of the benthic zone. “Neither squid nor shark desired outside help and interference,” Compton wrote in his narrative.
Baby Shark Rays Born at Newport Aquarium in Kentucky
Kentucky’s Newport Aquarium has announced that Sweet Pea, the first documented Shark Ray to breed in a controlled environment, gave birth to seven pups on January 24! Three females and three males survived the nearly five-hour birthing process, and are being carefully monitored.
Sweet Pea’s pups arrived during the same week as an IUCN report estimating that one in four shark and ray species are at risk of extinction.
A close relative of Stethacanthus, which lived a few million years earlier, the tiny prehistoric shark Falcatus is known from numerous fossil remains from Missouri, dating from the Carboniferous period. Besides its small size, this early shark was distinguished by its large eyes (the better for hunting prey deep underwater) and symmetrical tail, which hints that it was an accomplished swimmer. Also, the abundant fossil evidence has revealed striking evidence of sexual dimorphism—Falcatus males had narrow, sickle-shaped spines jutting out of the tops of their heads, which presumably attracted females for mating purposes.
In North America, the Great White Shark is primarily found off the coasts of California and the northeast, but they live throughout temperate and tropical oceans and can occur along the length of both coasts. While they can reach 21 ft (6.5 m) long, they actually average a more modest 13-17 ft (4-5 m) when mature.
Great Whites are relatively intelligent and can be fairly social. In South Africa where most Great White research is done, they have been shown to organize into clans like wolf packs, where each individual has a clear rank under an alpha leader. They are typically not violent in their social interactions with other Great Whites - they rely on rituals and displays to establish dominance. Interestingly, females are dominant over males in such situations.
They are ambush predators whose diet is composed of large vertebrates such as seals, dolphins or big fish like tuna. Most prey is taken by surprise from behind or below, typically in the early morning hours when visibility is poorer. Great Whites generally focus on species with higher fat content - humans are too bony to be considered appealing, but since swimmers or surfers can resemble some of their preferred prey (seals) attacks occasionally happen.
Brochoadmones came from the Early Devonian of Canada, about 435-430 million years ago. Around 10cm long (4in), it was a type of “spiny shark" — an extinct group that shared features with both bony and cartilaginous fish.
And it had a lot of extra fins. Six paired “finlets” running from below the gills to the pelvic fins, each consisting of a spine with a web of scaled skin. They look very much like what would be expected for multiple fins evolving from a lateral fin-fold (essentially a single elongated fin subdividing).
Electric rays are an order of marine cartilaginous fish known for their ability to generate electrical discharges. The shock can be used to stun prey and predators, and can range from 8 to 220 volts depending on the species (which is comparable to dropping a mains-powered hair dryer into a bathtub.)
The ray produces its electricity with a pair of specialised organs located on either side of the head, which consist of 400-600 columns. Each column is composed of a stack of around 400 gelatinous ‘electroplates’ which function like a battery connected in a parallel circuit.
Indonesia Announces World’s Largest Manta Ray Sanctuary
by Jane J. Lee
One of the world’s largest fishes gets a super-size sanctuary thanks to a decision by the Indonesian government to ban fishing for manta rays within the country’s exclusive economic zone (EEZ).
The move, hailed by conservation organizations and researchers, has resulted in the world’s largest protected area for these migratory animals. Indonesia’s EEZ stretches for almost 2.3 million square miles (6 million square kilometers). (Watch a video to learn more about manta rays.)
Two manta ray species, the reef manta (Manta alfredi) and the oceanic manta (Manta birostris), occur in the waters around Indonesia, and both are afforded protection under this new legislation…
Species in the Rhinochimaera family are known as long-nosed chimaeras. Their unusually long snouts (compared to other chimaeras) have sensory nerves that allow the fish to find food. Also, their first dorsal fin contains a mildly venomous spine that is used defensively. They are found in deep, temperate and tropical waters between 200 to 2,000 m in depth, and can grow to be up to 140 cm (4.5 ft) in length.
Chimaeras (also known as ghost sharks and ratfish) are an order of cartilaginous fish most closely related to sharks, but they have been evolutionarily isolated from them for over 400 million years.
(Info from WP and .gif from video by NOAA’s Okeanos Explorer—this is not an animation!)
Large, well-established and isolated Marine Protected Areas boost shark numbers
The concept itself probably doesn’t come as a big surprise to a lot of us, but a recent comprehensive study has shown that large, established and well-enforced no take zones show 14 times more more sharks and other sea life than commercial fishing areas.
87 marine protected areas (MPAs) were examined over 40 countries, allowing researchers to determine factors contributing to a successful MPA. Successful MPAs typically had five features: no-take zone, well-enforced, over 10 years old, over 100km-sq, and isolated by sand or deep water.
Of course, most of us also know that the majority of MPAs are not successful, and are in fact only token protected areas - they’re paper parks, meaning they’re only MPAs on paper. And the sea life in these areas is about on the same level as the sea life in the nearby fishing areas. Which is to say, not great; the study shows a 90% decrease in sharks, and 83% decrease in large fish (with a 63% decrease in fish overall). And that’s pretty scary, because it means a lot of MPAs aren’t achieving their conservation goals, if they have them at all.
But it’s not all bad news. Hopefully, this means the study and ones similar to it could be used in the near future to improve current MPAs, increase the number of successful MPAs and reduce the number of paper parks and MPAs like them. Fingers crossed.
(Also, you can read the paper, published in Nature, here.)
The marine biologists at Australia’s Oceanworld Manly aquarium may be well-versed in the facts of life, but it’s never too late to learn a bit more about how exactly babies are made. Recently, twelve healthy baby rays were birthed at the facility by a pair of females, much to the confusion of aquarium staff. What’s so puzzling about that? Well, the new mothers haven’t had any contact with a male stingray for over two years.
Researchers point out that some female marine animals, like rays and sharks, have been known to store sperm until just the right moment to conceive. But, according to a report from Australia’s Daily Telegraph, never before have biologists observed rays put off starting a family so long after the initial reproductive deed was done. In fact, pregnancy was the last thing on their minds when they noticed two of their rays were starting to plump up…
Aetobatus narutobiei | Naru Eagle Ray • A New Species of Eagle Ray from the Northwest Pacific: An Example of the Critical Role Taxonomy Plays in Fisheries and Ecological Sciences 
Recent taxonomic and molecular work on the eagle rays (Family Myliobatidae) revealed a cryptic species in the northwest Pacific. This species is formally described as Aetobatus narutobiei sp. nov. and compared to its congeners. Aetobatus narutobiei is found in eastern Vietnam, Hong Kong, China, Korea and southern Japan.
It was previously considered to be conspecific with Aetobatus flagellum, but these species differ in size, structure of the NADH2 and CO1 genes, some morphological and meristic characters and colouration. Aetobatus narutobiei is particularly abundant in Ariake Bay in southern Japan where it is considered a pest species that predates heavily on farmed bivalve stocks and is culled annually as part of a ‘predator control’ program.
The discovery of A. narutobiei highlights the paucity of detailed taxonomic research on this group of rays. This discovery impacts on current conservation assessments of A. flagellum and these need to be revised based on the findings of this study…
In the first global analysis of its kind, an international team of researchers found that of the 1,041 species of cartilaginous fishes (chondrichthyans) investigated, 25 species are critically endangered, 43 are endangered, 113 are vulnerable, and 132 species are “near threatened.” That’s a total of 30 percent of the species analyzed; for 487 of the remaining species, there was insufficient data to classify the threat…