#shark science

[moon-snailsss]

Great Hammerheads

Little info cards I made on the Great Hammerhead (one of my FAVORITE species)

[arisharkboi]

I've just learned that the USPS has stamps commemorating Eugenie Clark, an incredibly influential marine biologist, shark researcher, and SCUBA pioneer (and my personal hero!!!) Not only do you get cool stamps promoting women in marine science, you also get to support the USPS!

[protectoursharks]

There are four types of fish scales!

Cycloid scales are thin, overlap, and flexible. They're found on primitive teleosts (like minnows and carp).

Ctenoid scales have small, backwards pointed scales (known as cterns) make the fish more hydrodynamic and faster. They're found on Advanced Ctenoids (like perch and sunfish).

Ganoid scales are thick, diamond-shaped, and mostly non-overlapping. They're found on Chondrostei (like sturgeons and paddlefish).

Placoid scales are spikey and tooth-like with nerves. These are found on Chondrichthyes (like sharks and rays).

Ichthyology Notes 3/?

[nwmo]

LITTLE GUY SPOTTED

[feelingautistic]

Exciting news for the cute shark lovers of the world! We finally have a recorded sighting of a baby great white shark, likely only a few hours old.

The question of where great white sharks give birth still remains a mystery to this day but this footage may suggest the coasts of California, where the footage was taken, are a site where these sharks give birth.

[marinememes]

[jellyfishmakeoutparty]

the fact that I will never truly know what it’s like to be a shark in a shark cuddle pile is cruel and unusual punishment.

absolutely devastating.

[kookiekult]

[amnhnyc]

What makes the dark shyshark (Haploblepharus pictus) so shy? When threatened, this critter might curl up into a ring and cover its eyes with its tail. Scientists think this defensive posture makes it harder for predators to gulp the dark shyshark down for an easy meal. Found in parts of the southeast Atlantic Ocean, this shark can grow to about 22 in (55.8 cm) long. Its diet includes crustaceans, mollusks, and fish.

Photo: Raoulco, CC BY-NC 4.0, iNaturalist

[todropscience]

NEW HAMMERHEAD SHARK JUST DROPPED

Not every day does a new shark get discovered! Meet the Shovelbill Shark (Sphyrna alleni), a newly described species of hammerhead shark named after Microsoft co-founder and philanthropist Paul Allen. This new species is found in the coastal waters of the Caribbean and southwest Atlantic.

Hammerhead sharks are easily recognized by their laterally expanded and dorsoventrally compressed heads. Genetic studies have revealed that what was once thought to be a single bonnethead species (Sphyrna tiburo) is actually a complex, with Sphyrna alleni now recognized as a separate species. A longtime advocate for wildlife conservation, Paul Allen and his Paul G. Allen Family Foundation supported Global FinPrint, an international survey of the world’s reef sharks and rays. It was during this project that scientists conducted much of the fieldwork necessary to describe this newly recognized species. The Shovelbill Shark is smaller than the bonnethead, with distinct genetic and morphological characteristics, including a different number of vertebrae, which suggest it is separate from other hammerhead species. This new species is distributed from Belize to Southern Brazil, inhabiting estuaries, coral reefs, sandy and muddy bottom beds, seagrasses, and mangroves.

The Shovelbill Shark is a common component of artisanal fisheries in many Latin American countries and currently lacks proper management or protection. Previous reports indicate that this new species is undergoing overexploitation, making it imperative to safeguard their populations and establish fisheries regulations.

Photographs: Above is a male shovelhead shark (Sphyrna alleni), described from the Caribbean and the Southwest Atlantic. Below is Cindy Gonzalez, the lead researcher of the study, tagging the new species Sphyrna alleni (photo courtesy of the Mays Family Foundation).

Reference: Gonzales et al., 2024. Sphyrna alleni sp. nov., a new hammerhead shark (Carcharhiniformes, Sphyrnidae) from the Caribbean and the Southwest Atlantic. Zootaxa.

[moon-snailsss]

Elasmobranchs

What are elasmobranchs?

Elasmobranchii, a subclass of fish (Sharks, skates and rays), are characterized by their cartilaginous skeleton. Cartilage is a flexible connective tissue found in human ears and nasal tips. It provides Elasmobranchs with amazing flexibility. Elasmobranchs evolved over 400 mya, long before trees existed. They’ve adapted many unique adaptations that help them survive in the aquatic environment. Notably, their skin is covered in tiny tooth like structures called dermal denticles. Dermal denticles decrease drag and turbulence, allowing sharks and rays to swim with incredible speed and agility.

Shark Evolution

Shark evolution goes back 450 million years ago during the late Ordovician period. Scientists believe that sharks from this period did not have teeth. The earliest shark teeth scientists have discovered comes from an ancient fish that lived during the Devonian period. This fish is the Doliodus problematicus. They are described as the “least shark like shark.” Here’s an example of what shark teeth looked like during the Devonian period.

They look very different from todays shark teeth!

Stingray Evolution

Stingrays evolved from sharks. Sharks emerged 450 million years ago and stingrays evolved 200 million years ago. An adaptation that both sharks and stingrays have is the Ampullae of Lorenzini. Sharks, skates, and rays have these tiny mucus filled pores in their skin called the ampullae of lorenzini which can detect electricity in the water. They help elasmobranchs find prey by detecting electrical fields produced by prey activity.

Conservation

Unfortunately many species of elasmobranchs are endangered. This is mostly due to overfishing and shark finning. Shark finning is a practice where fisherman will cut off the fins of sharks and dump their bodies back in the water. It’s extremely inhumane and it causes sharks major suffering, without their fins they can’t swim and will end up suffocating. Overfishing and bycatch is another major problem where fisherman will accidentally catch unwanted sharks or Rays. Unintentionally caught animals will often die after being tossed back into the sea. Thankfully there are conservation efforts working protect endangered species. Organizations such as NOAA Fisheries and Shark Stewards are working to ban shark finning in different countries. Other organizations such as Minorities in shark science and shark research institute conduct research on shark species, helping people better understand sharks and protect them.

[sharkiedays]

Idk seems friendly enough

[eddieintheocean]

me and the bitches i pulled by being massive

[protectoursharks]

cutest shark facts?

Nurse sharks and white tip reef sharks form a pile and cuddle!

It's believed to be a form of social bonding and has helped challenge the "lone shark" assumption, allowing us to learn more about shark ecology and interaction!

[the-wolf-and-moon]

LDN 1235, Shark