As an island community we depend on the sea for so much - but it is also easy to take it for granted. In a monthly column, Dr Lara Howe, marine officer with the Manx Wildlife Trust, and Dr Peter Duncan, senior marine environment officer at DEFA, explore this underwater world and the lives of some of those who work there.

Last time we touched on some smaller critters that could be found in Douglas Bay but over the next few articles we are going to go bigger and discuss our ‘megafauna’, such as sharks, cetaceans (porpoises, dolphins and whales) and seals.

This article is about elasmobranchs, which are sharks, skates and rays, which are a group with cartilage skeletons - like the material in your nose or ears - compared to bony fish.

There are a variety of shark species that can be found in Manx waters, both large and small, from catsharks to the gentle giant, the basking shark, and everything in between.

Our smallest, most common species is the small spotted catshark, previously known as the lesser-spotted dogfish, growing up to 1m in length.

Often their spent egg cases, known as mermaid’s purses, can be found washed up on the beaches.

Other shark species found in Manx waters include bull huss (also called the greater-spotted dogfish, smooth hound, spiny dogfish, stellate smooth hound, spurdog and tope.

We have even had the odd thresher shark sighting around the Calf and in Ramsey Bay.

The main ray species around the island include thornback rays, cuckoo ray, spotted and blonde rays.

Little is known about elasmobranchs in our waters, where they can be found and in what numbers. Therefore, in 2013 DEFA and MWT set up the small shark tagging (SST) programme to gain a better understanding of these animals.

Experienced anglers tag small sharks with a small identification streamer tag on a catch and release basis.

We have tagged over 400 small sharks with two recaptures, but this is still incredibly exciting as one shark, in 2018, showed up off the coast of the Netherlands and the other last year in the Bay of Biscay.

This work shows how mobile these species are and how global co-operation is needed if they are to be protected.

Last year was also the first year we tagged thornback rays.

Now to our largest shark, the basking shark. The island is a great place to see basking sharks in the summer, usually between May and September.

They feed on plankton, the small, microscopic algae and animals that form the lower part of the food chain.

They can often be seen feeding at the surface around our south-west coast, with their large dorsal fin and tail protruding above the surface.

In Manx they are called gobbag vooar, which means big mouth, which if you have been lucky enough to get close enough you will know why they get that name!

Considerable research through Manx Basking Shark Watch, now transferred to Manx Whale and Dolphin Watch, has also highlighted the mobile nature of these large sharks. The satellite tag data have shown one individual travelled across the Atlantic to Canada while the majority head south to the Bay of Biscay for the winter, like our smaller sharks.

Unfortunately, many shark and ray species are threatened due to their slow growth rates and long reproductive cycle – even the spotted catshark spend nine months developing in its ‘mermaid’s purse’ .

Historically huge numbers of sharks have been killed for their fins, liver, and other body parts and, while this has reduced in our region, they still face challenges such as climate change, pollution and being caught as bycatch, even here on the island. Therefore, monitoring these species is key to gaining a better understanding, to ensure we can protect them for future generations.

If you want to get involved in shark conservation, why not do an egg case hunt on your local beach and record how many you find and what species they belong to.

The Shark Trust has some great resources you can download at sharktrust.org/greateggcasehunt

Don’t forget to let us have your egg case sightings too.

Alternatively, if you are an experienced angler and want to get involved in conservation, why not join our SST programme. See our website for more information: mwt.im/citizen-science/shark-tagging