Have you seen a freshwater sponge?
Freshwater sponges come in a wide range of shapes and sizes and have been reported from various locations in Wales, and are frequently seen by divers in particular. They occur in a wide range of habitats including mountain streams, lakes, canals and lowland rivers. You may encounter them at any time of year growing attached to hard substrates such as rocks and stones, woody debris, aquatic plants, artificial structures and mussel shells. In winter the colonies shrink and produce resting bodies called gemmules.
There are about 5 species of freshwater sponge known from Britain, but almost nothing is known about their distribution or habitat preferences.This is mainly because sponge identification is a specialist task, so sightings are rarely recorded. This is where you can help.
Karen Evans is currently working on sponges in Britain. She is interested in finding out more about their distribution and is willing to identify specimens sent to her. Specimens should be sent by post in a small tube preserved in a little alcohol (vodka is ideal). A sample of about 1cm across is enough for identification, but it's greatly preferable if the piece contains gemmules (usually visible as small dark seed-like objects).
Tristan Hatton-Ellis (CCW)
On the Record
On the Record is our monthly online newsletter. It's full of interesting information about local wildlife recording, including that month's events and what to look out for in our Species Focus feature. Subscribe now to get next month's issue .