Reproductive biology of two deep-sea octocorals in the Azores Archipelago

• Published in: Deep-sea research. Part I, Oceanographic research papers Oceanographic research papers, 2021-09, Vol.175, p.103587, Article 103587
• Main Authors: Rakka, Maria, Sampaio, Íris, Colaço, Ana, Carreiro-Silva, Marina
• Format: Article
• Language: English
• Subjects: Cold-water corals; Coral garden; Gametogenesis; Marine animal forest; Reproduction
• ISSN: 0967-0637; 1879-0119
• DOI: 10.1016/j.dsr.2021.103587

Octocorals are prominent habitat builders in deep-sea ecosystems. The octocorals Dentomuricea aff. meteor and Viminella flagellum are common deep-sea octocoral species in the Azores Archipelago, where they form dense, structurally complex and diverse communities between 150 and 600 m of depth. The objective of this study was to determine the reproductive biology of the studied species, including basic reproductive traits, gametogenic cycle and reproductive timing. Specimens were collected during 2010 and 2011 as by-catch from deep-sea long-line fisheries and scientific cruises and were histologically processed. Both species were found to be gonochoric and most likely broadcast spawners. Gamete presence was observed throughout the study period, indicating continuous or quasi-continuous gametogenesis. In some sampling sites gametogenic peaks were found in October for D. aff. meteor and May for V. flagellum, however oocyte size distributions and fecundity did not display any marked seasonality throughout the region. Reproductive knowledge is rarely available for deep-sea octocorals, despite its fundamental importance, and relevance in management and conservation. •Dentomuricea aff. meteor and Viminella flagellum were gonochoric, most likely broadcast spawning, with female-skewed sex ratios•Female colonies of the two species displayed gamete presence throughout the study period, indicating continuous or quasi-continuous gametogenesis•Oocyte size distributions and polyp fecundity did not display any evident seasonality•Viminella flagellum invested in larger oocytes compared to Dentomuricea aff. meteor with possible implications for larvae characteristics