Annual reproductive periodicity of the sea urchin Diadema antillarum Philippi in the Canary Islands

The tropical sea urchin Diadema antillarum is found on both coasts of the A tlantic Ocean. Several studies exist of the reproductive cycles of western Atlantic populations, but despite the extreme abundance of the species in t he Canary Islands, nothing is known about its reproduction in this region. We present data on annual reproductive periodicity of eastern Atlantic popu lations. We determined gonadal indices at two locations in the island of Gr an Canaria, Canary Islands. Though water in the southern location is warmer , reproductive cycles are similar. Gonadal content increases between Octobe r and April (or May), then declines (presumably due to spawning) until Sept ember (or October). The spawning season coincides with the period of most r apid temperature rise, but the new reproductive cycle is initiated as tempe rature continues to increase. In addition to temperature, reproductive cycl es may be related to seasonal increases of benthic algal productivity.