Are you ready to learn some cool facts about local sharks? We are bringing you the ultimate A-Z of shark facts, kicking off with A for.... Apex predators.
Sharks are usually placed at the top of the marine food chain, having no natural predators 🦈
They play an important role maintaining the health of our seas by keeping fish populations balanced 🐟
The removal of these amazing predators may lead to altered marine food webs and maybe even the loss of marine species!
B is for...Bullhuss! The Bullhuss is a shark species found in our local waters that reaches an average length of 160cm 🦈
The Bullhuss lives on the seafloor and hunts at night for its favourite foods, such as squid, octopus and crabs 🦑🐙🦀
C is for...Catshark! The most common species of shark found in our waters is the Small spotted catshark 🦈
Northern Irish coastal waters offer important nursery grounds for these species. Have you found a catshark eggcase on your local beach?
By recording shark & skate eggcases you can help us discover more about these incredible species in our waters.
D is for...Denticles! Sharks skin is made up of rows of V shaped, armoured plates called dermal denticles 🦈
These denticles protect sharks from injures and parasitic infections! The shape of these denticles also helps reduce hydo-dynamic drag, allowing sharks to propel through the water and be some of the speedist species in our seas.
E is for...Egg cases! Also known as mermaids purses, empty shark & skate egg cases wash up on shores around the Northern Irish coast 🦈
Recording any egg cases you find is vital to help understand the different shark & skate species present in our waters. Egg cases can also indicate potential spawning sites and nursery grounds for young shark pups!
F is for... Flapper skate! The Flapper skate is the worlds largest skate species and we are lucky enough to have it residing in our local waters 🌊
However, the Flapper skate is critically endangered. The Sea Deep project is working to conserve the Flapper skate by building evidence of species presence through an NI wide tagging programme. Through this programme the Sea Deep project has been able to identify potential Flapper skate 'hot spots' that are being used frequently by the species! It is hoped with this knowledge we can work to protect these sites and safeguard the future of the Flapper skate in our local waters.
G is for...Gills! Sharks 'breathe' through the use of their gills, a respiratory organ that carries out a similar function to human lungs!
On average shark species have 5-7 pairs of gills on each side of their head. Water is forced over the gills through a process known as ram ventilation. Oxygen is then extracted from the water by tiny blood vessels in the gill slits.
H is for... Hunting! Sharks are skilled hunters, preying on a variety of marine species... such as fish, squid and crustaceans 🐟🦑🦀
They use unique adaptations such as their ampullae of lorenzini to detect prey or spiricles to assist in ambushing their next meal 🍽
Sharks prioritise preying on injured or older individuals, placing a natural selection pressure on a species populations. This maintains a balanced and healthy marine food web 🦈
I is for... IUCN red list! The IUCN (international union for conservation of nature) red list evaluates the extinction risk of 1000's of species. Using a strong scientific base, species are categorised as either least concern, near threatened, vulnerable, endangered, critically endangered or extinct depending on species population size and continued decline!
Criteria is assessed globally and locally. In Northern Irish waters some elasmobranch species such as the Small-spotted catshark are categorised as Least Concern. However, many of our local sharks and skates fall within the vulnerable to critically endangered categories, for example the critically endangered Flapper skate.
The sea deep project is working to increase local elasmobranch population numbers, safeguarding the future of these species in our waters.
J is for Jaws! (The movie)... Yes, you read that right! The idea that sharks actively seek out and attack humans, portrayed in the popular movie Jaws, is inaccurate. However, this has become a preconception of shark behaviour globally.
Sadly, there are approximately 10 fatal incidents for humans involving sharks annually... however on average 100 million sharks species are killed by human induced pressures every year.
K is for...Kitefin shark! The kitefin shark isn't a species you're likely to come across in our waters...but that is because they live in the deepest waters around our coasts 🌊
The kitefin shark grows on average 160cm and can live to 18 years! They give birth to live young, usually having 6-8 pups.
As kitefin sharks live in deeper waters, they are commonly caught as bycatch in deep sea trawlers. When this occurs kitefin sharks are often returned to the sea but unfortunately have low survival rates. Coupled with a combination of slow reproduction rates the kitefin shark has been categorised as Near Threatened on the IUCN red list.
L is for... ampullae of Lorenzini! The snout of a shark is covered in a network of jelly filled pores called their ampullae of lorenzini. This network acts like a sixth sense for sharks by detecting electrical fields in the water⚡
Ampullae of lorenzini help sharks detect weaker muscle contractions in potential prey and can even sense electric currents induced by the earth's magnetic field... helping sharks orientate in the ocean 🌎
So these impressive organs provide a sixth sense to help sharks survive in their environment 🦈
M is for... Marine protected areas! Marine protected areas or MPAs are areas of the sea were specific management measures are put in place to safeguard marine species and habitats 🌊
Northern Irish waters are home to the critically endangered Flapper skate, one of the largest and rarest skate species in the world! Our coastal waters provide a fundamental refuge for this species. Tagging data has shown Flapper skate foraging in NI waters and recaptures have highlighted site fidelity, meaning Flapper skates are remaining in our waters.
A well implemented MPA for the Flapper skate could provide an opportunity for the species to recover in numbers and be conserved for future generations.
To ensure MPA site selection is effective we need to know as much as possible about how the Flapper skate is using our waters. Sea Deep tagging programmes and egg case surveys are helping collect this valuable data.
N is for...Nutrition! Sharks and skates eat a wide array of prey, with preferred food sources varying from species to species 🦈
Some of our local skates, such as the Flapper skate feed mainly on crustaceans with their plate like teeth crushing the hard exterior of species such as crabs 🦀
Sharks maintain their nutritional needs by catching prey with their rows of teeth. Shark teeth vary in shape and size, depending on the species. For example, the Porbeagle (found in our local waters) has sharp pointy teeth to help them catch more slippery prey, like squid 🦑
O is for... Ovoviviparous reproduction! Sharks, skates and rays have three main modes of reproducing young- oviparous reproduction, viviparous reproduction and ovoviviparous reproduction.
Ovoviviparous reproduction is when a species produces young by the means of eggs that hatch within the body of the parent. Spurdogs, a species of shark that can be found in our local waters, produce young by this method. Spurdogs also have one of the longest pregnancies of any vertebrate, lasting on average two years!
Many of our local skates have young via oviparous reproduction, meaning they lay eggs that hatch outside the body! Empty eggcases often wash up along our shores and recording them can help us build an idea of what species are using our local waters.
P is for...Porbeagle 🦈 The Porbeagle is one of the larger sharks found in our waters, reaching lengths of 2 metres or more and weighing in at an average 135kg. The Porbeagle is also in the same family as the Great white shark!
Unfortunately the species is listed as critically endangered in the North East Atlantic. The Sea Deep tagging programme is working with volunteer anglers to gather data on the Porbeagle. By tagging the Porbeagle we can begin to understand population size and distribution in our waters more clearly, helping us safeguard these species for future generations.