Some Observations on the Reproductive Biology of the Mediterranean Pennatulacean Pteroeides Spinosum (Ellis and Solander, 1786) (Cnidaria: Octocorallia: Pennatulacea)

Abstract Sea pens are some of the most important structural species in soft bottom benthic communities. Pteroeides spinosum is a shallow-water pennatulacean (Cnidaria: Octocorallia: Pennatulacea) habiting NE Atlantic-Mediterranean bottoms. In this study, sixteen colonies collected from NW Mediterranean (Cap de Creus, Spain) at 99–106 m depth July (2012), were used to acquire information their reproductive biology, and enable comparison with other pennatulaceans. Our gonochoric showing bimodal oocyte frequency distribution an unimodal spermatocyst diameter distribution. All polyp leaves contained oocytes spermatocysts different size classes, those small translucent spermatocysts/ (size-class I) often found near base or lower end gastrovascular cavities polyps. The largest observed was 668 μm for 687 oocytes. Mean potential relative fecundity (PRF) ranged between 7–17 per polyp. effective effort (ERE) reached value ca. 30,000 large colony. As all pennatulaceans previously studied, no sign hermaphroditism internal fertilization detected our .