Paul Naylor explores the lonesome nature of reproduction among some sea anemones
Plumose anemones of assorted sizes thriving near the Menai Straits
CRITTERCONFIDENTIAL
No sex please , we ’ re sea anemones
Paul Naylor explores the lonesome nature of reproduction among some sea anemones
I
couldn ’ t resist that title , harking back to the classic comedy [ best forgotten – Entertainment Editor ], but I ’ m afraid it ’ s somewhat misleading because sea anemones can of course reproduce sexually . It is , however , their capability for also reproducing prodigiously without sex that gives us some of the most stunning
20 underwater scenery around the UK .
The best-known exponent of asexual reproduction is the small but mighty ( in terms of beauty ) jewel anemone , Corynactis viridis . It does it by a process called ‘ longitudinal fission ’ where an individual anemone stretches its base and then splits down the middle , to produce two
A few sea urchins graze but Jewel anemones dominate the rock face new anemones . The procedure apparently takes a few hours and , although it is very unusual to observe it actually happening , its results are clear to see . Jewel anemones occur in many different colour forms and the splitting process occurs again and again to produce a large patch of anemones , all of the same colour . Vivid patches of different and brightly coloured anemones can then cover a rock face and provide that wonderful vista for us to admire , particularly in good visibility on an offshore reef .
A different method of asexual reproduction can be used by the larger but less showy elegant anemone ( Cylista elegans ), which is common on rock faces just below the kelp zone . Incidentally , if you ’ re a keen marine life recorder thinking ‘ I thought that was called Sagartia ’ it ’ s yet another species that has had its scientific name changed ! Elegant anemones reproduce asexually when small pieces of tissue break away from their base and develop into tiny new individuals . The species occurs in five colour varieties that look so different they were once thought to be separate species . While the ‘ basal