Morphological, Physiological and Cytological Aspects of Reproduction in Scleractinian Corals

Reproductive strategies range from true gonochorism (separatesexes) to true simultaneous hermaphroditism (both sexesfound simultaneously) and may change with age or size of theindividual or colony.Sexual maturity may be age or size dependent and may bedriven by a combination of genetic and environmentalparameters.The anthozoan reproductive system consists of 'simple'gonads found within the body wall or in the mesenteries. Thegonad begins in the endodermal tissue with a population oftotipotent interstitial cells (stem cells) able to differentiateinto either somatic or germ cells and the differentiation programdirects gamete development.Anthozoa do not sequester germ cells throughout their lives,but develop them de novo from a presumptive germ stem cellduring each new reproductive season.Germ cells develop into male or female gametes dependingon genetic as well as epigenetic factors.Anthozoan gametogenesis and spawning varies with specieswith some occurring year round and other at very specificand in short times periods.For zooxanthellate corals, symbiont acquisition may occur atdifferent developmental stages that include being transferredfrom the follicular cell layer into mature oocytes or duringplanula brooding or in the free-living planula stage.Corals have differing modes of gamete dispersal, i.e. broodingor broadcast spawning, that differs between species and caneven differ within species of different geographical locations.Environmental