1. Four species of Indo-Pacific echinoderms, the echinoidsDiadema setosum andEchinometra mathaei, the asteroidLinckia laevigata and the holothuroidHolothuria atra, are reproductively active and spawn more or less continuously, when they occur near the equator. 2. Gametogenesis is synchronous among individuals ofD. setosum, and spawning occurs rhythmically, probably more or less monthly, during the spawning period. This spawning rhythm does not seem to be related to lunar phases as previously reported. When further than 10–15° latitude from the equator, reproductive activity becomes more and more restricted, until at about 30° latitude the spawning period is limited to the summer months. 3. Gametogenesis is asynchronous among individuals ofE. mathaei, L. laevigata andH. atra, and different individuals spawn at different times during the spawning periods. Some individuals ofE. mathaei are reproductively active at all times of the year throughout most of its distribution, except when north of about 27° N. latitude when reproductive activity is limited to the summer months. 4. Sea temperature seems to be important in regulating the reproductive periodicities of at least two of the species.D. setosum is reproductively active when the temperatures are above about 25° C., andE. mathaei is reproductively active when the temperatures are above about 18–20° C.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 4 - ethologie animale