Becoming a marine life citizen scientist –  data gatherer & recorder

Shetland has almost 1,700 miles of coastline. You can find many boulder-strewn storm battered beaches as well as gorgeous stretches of white or golden sand. The coastline can look dark and ominous some days and like the Caribbean the next, Shetland has so many beautiful beaches, you are never far from a good one! Spending time on the coast, breathing in the fresh Northern salty air feels good !! and has well known health and wellbeing benefits. Whether you are exercising the dog, having family fun building sandcastles, braving a wild swim, beach cleaning, walking, birdwatching, orca spotting or beachcombing, there are plenty of ways to enjoy our fine beaches. Having spent a lot of my childhood in a flat, land-locked county in England, I have always really appreciated the coast, and over the past twenty years have forged a deep love of Shetlands coastline and marine environment – indeed I could never move away from the coast and the sea – it has become my happy place for both business and pleasure!

As a family, we spend a lot of time in the winter and spring months walking and beachcombing on our favourite beaches. We look for dead seabirds as part of beached bird surveys, hunt for groatie buckies (cowrie shells), rare sea beans and drift seeds from South America, pea urchins, sea urchins and sea glass. On many walks, particularly after storms when seaweed mounds are strewn across the tideline, we look for mermaids purses, otherwise known as shark, ray and skate eggcases. It is unusual to leave a beach and not have at least a couple of eggcases in our pockets. Beautiful rectangular or square empty vessels, light and wonderfully variable in colour, they are always a joy to find! Our eggcase journey began many years ago when, on finding our first few, we were keen to find out what species they were from and how common or rare they were. This is when we came across a fabulous website and resource we have revisited many times since. Here you can learn about the different species in UK waters (and beyond!) and about their unique lifestyles. You can identify eggcases you find using their excellent identification charts (see an example below), they even have child friendly identification charts and themed eggcases hunts like the Easter-themed one! Once you identify your find, you are encouraged to submit your record on the easy to use recording page where you can upload a photo, add your species, location and date.

© Shetland Seabird Tours 2024

“We believe in the power of collective action. Citizen science is a great way to get more people involved in shark conservation and research. And solve the problem of data gaps at the same time. Research is the first step to conservation. We need to know as much as we can about how a species lives and the threats they face. This enables us to make well informed decisions to help better protect them. Over the years we’ve built up some major citizen science projects, including our flagship project the Great Eggcase Hunt.The power of citizen science is that it allows us to collect vast amounts of data. It also helps us pinpoint where further scientific study is needed”.

“Some sharks, and all true skates, reproduce by laying eggs. These are surrounded by a tough leathery capsule that protects the embryo as it develops inside. After several months these are ready to hatch, and a fully-formed shark or skate will emerge. Please note that in the UK many skate species are referred to as rays in their common names. Once empty, the eggcases (or mermaid’s purses) often wash up on the beach. One of the best places to find them is among the strandline, where the seaweed washes up. The eggcases of different species vary. So, by looking at the size, shape and features, we can tell which species laid it. You can learn to identify eggcases too”

Small spotted catshark eggcases are the most commonly found on Shetland beaches.

“The Great Eggcase Hunt has helped us to build a clearer picture of which species are present around the world, and more specifically around the British Isles. To date, 98% of our records come from around the British Isles, totalling over a whopping 430,000 eggcases; 87% of which have been verified by either an image, a specimen or expert ID. Though there are around 30 egg-laying species that occur around the British Isles and Ireland, many of these are offshore or deeper waterspecies. Due to this, our ID guide for the Northeast Atlantic contains the species that are most likely to wash ashore; giving us 13 key species for this region. Although the Starry Skate, Blue Skate, White Skate and Blackmouth Catshark are rarely reported, there have been beach finds for these species. In contrast, nearly 55% of eggcases come from just two species: the Thornback Ray and the Smallspotted Catshark!”

“Starting from a chance eggcase find in 2003, this project has grown and spread faster and further than we could have dreamed. 2023 marks 20 years of this citizenscience project, with thousands of people having taken part over the years. Through the tireless effort and commitment of the public and our citizen scientists, the Great Eggcase Hunt now holds records of over 440,000 eggcases! Starting from just 127 eggcases reported in 2003 from around 50 people, we have had over 40,000 eggcases reported in the first half of 2023 alone, from nearly 5,000 people! Better still, with digital cameras and smart phones becoming more and more common, a greater proportion of our records have been coming through with images attached; 87% of our records so far have been verified.” The Shark Trust



We have found hunting for and then recording eggcases found on Shetland an incredibly fun and rewarding pastime and one which involves and inspires all the family at all times of the year. You can record your finds even easier now with the new Shark Trust Eggcase recording smartphone APP which was released last year:

Shark Trust Mobile App Download Guide

Shark Trust Junior Eggcase Guide Download

Shark Trust Indoor Easter  Eggcase Hunt Download

Shark Trust  – Become a Member

Eggcase Recording Form – Shark Trust

2003 to 2023 THE GREAT EGGCASE HUNT – Records that matter – SHARK CONSERVATION  – get involved!


Rebecca, Phil & Ayda – Shetland Seabird Tours – The Noss Boat




“This is an offshore species (mostly at 200 – 500m depth), so eggcases are rarely washed ashore and reported to the Great Eggcase Hunt. Distribution: Within the British Isles, most eggcases have been reported from Porcupine Bank – which is an area off western Ireland. Records: so far we have had 63 verified records, 16 of which have come from the UK and Ireland” Shark Trust

  1. 4th February 2024  – Bannaminn Beach – Shetland (specimen now with UHI. – Shetland).
  2. 7th March 2024 – Bannaminn Beach – Shetland
BLACKMOUTH CATSHARK EGGCASE ©Shetland Seabird Tours 2024
BLACKMOUTH CATSHARK EGGCASE ©Shetland Seabird Tours 2024