COAST and Seasearch diver Claire Youdale describes her experiences when attending a specialist course which, among other things, will help her to

identify those creatures from the perhaps less glamorous, but amazingly varied world of hydroids and bryzoans...

The recent hydroid and bryzoan specialist course run by Dr Jo Porter of Heriot-Watt University saw an excellent turnout from Seasearch north east, Seasearch Scotland and Seasearch north Wales members. The course was organised by Carrie Pillow and was run from the Fisherman's mission in Eyemouth.

The weekend started off with some background into hydroids and bryzoans, their life history, body morphology, feeding and general identification features. The aim for the weekend was to be able to identify 20 species of these animals which personally at least doubled the ones I could currently spot!

Bryzoa and hydroids are colonial invertebrates feeding on plankton with tiny tentacles like little hands grabbing at the plankton. Bryzoa means 'mossy animal' and are often termed sea mats or sea mosses as they regularly, but not always, encrust seaweeds and rocks. Some look like tiny bushes growing out of the rock face. Hydroids are cnidarians which is the same phylum as jellyfish. All cnidaria have stinging cells to enable them to tackle slightly larger prey and grow erect on rocks and seaweed and sometimes even crustacean shells like hermit crab fir (Hydractinia echinata).

Once we’d got to grips with the background we spent some time identifying preserved specimens under the microscope before heading out for a dive with Marine Quest on their boat 'North Star'. The weather was a bit blustery so we headed around the coast east of St Abbs Head for some more sheltered diving at Thrummie Carr. Everyone went down armed with a small sample bag to collect  specimens for identification on Sunday. It is amazing how much more you see when you know what you are looking for and what had previously been recorded as encrusting bryzoan species now could be given a name. The variety in these animals is astounding, some grow encrusting the rocks, others sprout like plants from boulders and seaweed.

Back on the surface we stored all the specimens in seawater and retired to the pub for a well earned dinner.

Day two was dedicated to identifying the species we had collected on the previous day. We looked at the general morphology, what could and couldn’t be identified in the field and compiled a list of the species found on the dive. Using microscopes many species could be observed giving us a level of detail you wouldn't otherwise see. We certainly topped our target of finding 20 different species!

The course was brilliantly run and organised and it was great to meet someone like Jo who is clearly passionate about these often overlooked animals. I may still not be able to identify 20 species in the field but I left the course feeling much better equipped to fill in the hydroid and bryzoan section on my Seasearch form next time I go out diving.