Lugworms bury deep in the sand, and are responsible for the swirled casts so often seen on sandy beaches. What is more surprising is that they are also responsible for "sperm puddles" seen on top of the sand during the autumn and winter, as a method of reproduction. We are interested in when these puddles appear at different shores in the UK. This study will provide an insight into what environmental conditions trigger them to reproduce – something scientists have struggled to find out!


On a local sandy shore.


We are trying to survey every three days from the 15th October until the 3rd December to catch when the lugworms may be reproducing.


Using a walkover survey for 50 m, repeated three times over low tide. Scroll down to find instructions and recording sheets and get in touch with your local hub to sign-up to a shore.

Upload your survey data here: https://www.surveymonkey.co.uk/r/spermwatchdataentry


It is an easy survey to take part as you don’t need any training and all the family can take part. It is easy to complete and if you have a sandy shore close by it won’t take long at all to do. Who else gets to look for sperm puddles for science?

Additional Activities

As part of Capturing Our Coast, our regional hubs run additional activities throughout the year to help us further understand the UK coast. These additional citizen science activities are experimental investigations that allow us to research things like breeding cycles of key species and wader bird use of coastal and intertidal environments. These activities are open to trained and non-trained volunteers of all ages.


Beach Babies

 Would you like to look for “beach babies” on your local rocky shore? Some species start to...


Bird Food

Rocky shores aren't just about the small animals. Many species of wading bird are in decline,...



Lugworms bury deep in the sand, and are responsible for the swirled casts so often seen on sandy...


Seaweed vs Limpets

Limpets are grazers that live on algae, and an important part of the rocky shore ecosystem. The...


Further Activities

These experimental investigations are open to our Capturing Our Coast trained volunteers only. To find out more about the options available, follow the links below.


Invasive Seaweeds

We are interested in a species of seaweed called Japanese wireweed (Sargassum muticum). It is an...

Topshell Turvy

Topshells are a group of colourful seashells that graze on algae along the shore. Different...

Race to Recovery

Storms and rough seas can clear huge areas of rocky shores by churning stones and large waves...

Barnacle Photographs

Barnacles are common on many shores, but we know very little about individuals among the masses...

Barnacle Babies

Barnacles produce eggs and release larvae into the water that spend time swimming freely and...

Man-Made Habitats

We want to compare differences in the communities of animals and seaweeds that occur on natural...