Join the Great Eggcase Hunt

22/01/2013 by Our Ethics admin

Join the Great Eggcase Hunt. Taking place on a beach near you!

To compliment our Responsible Fish Sourcing Policy, we run a number of community marine biodiversity projects across the UK.

In 2013, we hosted six Great Eggcase Hunt events around the Britain, in partnership with the Shark Trust. Co-opeartive members attending the events helped to gather crucial information about the species of shark, skate and ray found in British waters, contributing to vital research and conservation work.

Over 250 Co-operative members joined in 2013 - read about some experiences from these events: 

Before embarking on each search, an expert from the Shark Trust will explain to eggcase hunters all they need to know about eggcases, where to find them, how to identify them, and importantly, how to record their finds.

Sharks, skates and rays in British waters

Catshark © Dave PeakeBritish waters are home to over 50 species of shark, skate and ray (collectively known as elasmobranchs), but the breeding areas and population sizes of individual species are poorly understood, increasing the difficulty of ensuring they receive the level of protection they need. Over half of the species found in British waters are classified as threatened or near threatened by the International Union for Conservation of Nature (IUCN) Redlist.

Many of these species are apex predators which play a vital role in keeping the marine ecosystem in check. Globally, shark populations have declined rapidly since industrial fishing commenced.


Eggcase attached to seaweed © The Shark TrustMany species of skate and ray, along with some sharks, reproduce by laying tough, leathery eggcases, known as “mermaid’s purses”. These eggcases remain on the seabed or attached to seaweed for several months while the embryo inside develops into a miniature version of the adult. Mermaid’s purses are much lighter once the embryo has hatched, and when dislodged, can be picked up in currents washed up along the shore.

Co-operative members, taking part in the Shark Trust’s Great Eggcase Hunt, will use an identification guide to discover which species hatched from the eggcase and then record the location where it was found. This will complement data and information collected for wider conservation work.

Eggcases are much lighter once the embryo has hatched, and when dislodged, can be picked up in currents and carried inshore by wave action where they are washed up along the strandline. By walking along the strandline and keeping your eyes peeled, you are giving yourself a good chance of finding eggcases!

Eggcases may indicate that nursery grounds are nearby and identifying these grounds can assist in the conservation of sharks, skates and rays. Eggcase records are a crucial element of this conservation work.

About the Hunt

On the Hunt in PlymouthThe Great Eggcase Hunt was established by the Shark Trust in 2003, and has since identified and recorded over 32,000 eggcases:

The Great Eggcase Hunt is one of two projects we are currently collaborating on with the Shark Trust. The understanding of the abundance and distribution of the shark species in our waters is poor, and little is known of the location of important nursery grounds. Without this knowledge, it’s extremely difficult to ensure at risk species are given the protection they require.

Due to the difficulties of assessing the population and distribution of animals in the sea, there are currently just two ways in which we can begin to piece together the full picture of sharks, skates and rays in our waters – through looking for evidence of their breeding washing up on our beaches – The Great Eggcase Hunt – and by working with fishermen to help them improve the accuracy and quantity of catch records. Read more about our other work with the Shark Trust.

Images: Catshark (top) Dave Peake; Eggcases attacehed to seaweed (right) The Shark Trust