A hunt for shark eggs

Posted: 2nd November, 2018

This year over 157 amazing volunteers joined staff from The Deep to hunt for shark egg cases.

16 species of skate and ray and two species of shark regularly recorded in UK coastal waters reproduce by laying tough leathery egg cases, each of which contains a single embryo. After a number of months incubating on the seabed, anchored to rocks or seaweed, a fully formed pup emerges. Once hatched, the empty egg cases wash ashore in the changing tides, offering an easy way to monitor our shark population.

This year has seen the highest number of egg cases found in The Deep’s hunts, with 562 egg cases collected at Spurn Point in just 2 hours. ‘The Beast from the East’ may have helped wash more empty cases ashore. In comparison to the rest of the country, the Yorkshire coastline is under documented, but thanks to the efforts of volunteers we can see we have a healthy population of sharks.

Cat Gordon, Conservation Officer at The Sharks Trust said: "The Great Egg Case Hunt has logged over 200,000 mermaid’s purses since the project began in 2003. If you take a look at the results maps on the Shark Trust Website you’ll see that the majority of the UK coastline has been well represented thanks to eagle-eyed citizen scientists. These records give us a good indication of the broad distribution of egg laying sharks and skates.

“We typically get more egg cases submitted from the west coast than from the east. However sticking out into the North Sea at the mouth of the Humber Estuary, Spurn Point seems to offer a good egg case hunting spot. Small-spotted catshark egg cases are the most likely find along with spotted rays and thornback rays, but the occasional starry skate egg case can also be seen. We’ve had over 1000 egg cases recorded from here this year, with half of these found during The Deep/Yorkshire Wildlife Trust’s dedicated events. While the Great Egg Case Hunt documents ad hoc finds, if beaches can be surveyed regularly then each year we can compare results and see how numbers fluctuate."

More events are planned for 2019, so there are lots more opportunities to become citizen scientists: Watch The Deep’s website for more details.

Or to submit your own egg case finds, visit: https://www.sharktrust.org/en/great_eggcase_hunt

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