Evidence for Sequential Hermaphroditism in Sabellastarte spectabilis (Polychaeta: Sabellidae) in Hawai'i

Abstract

Understanding the reproductive characteristics of Sabellastarte spectabilis (Grube, 1878), an economically important polychaete worm collected for the aquarium trade, is essential to the development of artificial propagation and conservation of coral reefs. The purpose of this study was to determine whether S. spectabilis is hermaphroditic. Using histological techniques, 180 individuals were examined for gametes. Gametes were present only in abdominal segments. Primary oocytes were 7-8 mm in diameter in histologically prepared sections. Sperm appeared as round black dots about 2 mm in diameter on histologically prepared slides. Most individuals sampled had only one type of gamete in the coelom, but both eggs and sperm were seen in the coelom of 15% of individuals, demonstrating the occurrence of hermaphroditism in Hawaiian populations of S. spectabilis. The sex ratio of males to females was skewed significantly toward males in both the small (6-8 mm diameter) and medium (9-10 mm diameter) sized worms. Among the largest worms (11-13 mm diameter), the sex ratio did not diverge significantly from 1 : 1. There was a significantly higher proportion of hermaphrodites (30%) in the large size class. Worms of unknown gender, although present in all size classes examined, were most frequent (33%) in the medium size class. These patterns are consistent with sequential (protandrous) hermaphroditism.

A taxonomic guide to the fanworms (Sabellidae, Annelida) of Lizard Island, Great Barrier Reef, Australia, including new species and new records

“…Sabellids are generally considered as common in coral reef environments (Rouse 2000;Goldberg 2013). Many species (e.g., members of the genera Chone, Euchone, Jasmineira, Paradialychone, Perkinsiana-see Capa 2007;Tovar-Hernández 2008;Capa et al 2014) seem to inhabit sediment bottoms but there are several taxa that live attached to hard substrates or occupy crevices and holes in dead coral rubble or rock (e.g., members of the genera Bispira, Branchiomma, Glomerula, Pseudobranchiomma, Sabellastarte-see Fitzsimons 1965, Perkins 1991, Bybee et al 2006, Capa et al, 2013 and others that are even able to penetrate into the calcareous coral structure (e.g., members of the genera Megalomma, Notaulax, Perkinsiana and Pseudopotamilla-see Chughtai & KnightJones 1988;Nishi & Nishimira 1999;Fonseca et al 2006).…”

Advances in Breeding and Rearing Marine Ornamentals

“…To harvest these organisms, collectors commonly employ destructive techniques (such as the use of crow‐bars) that damage delicate corals and other organisms surrounding the tube worm. As a consequence, studies on marine ornamental tube worm reproduction and life cycle is of paramount importance for the establishment of suitable culture protocols (Bybee et al 2006a). By culturing tube worms in captivity, it will be possible to decrease the fishing pressure on wild populations as well as contribute to the preservation of coral reefs by avoiding the use of destructive collecting practices (Bybee et al 2009).…”

“…Presently, it is known that S. spectabilis is a protandric hermaphrodite (first maturing as male during its life cycle and later as female; Bybee et al 2006a). This species displays a long gametogenic period and an extended potential spawning season, which seems to be correlated with water temperature (maturation appears to coincide with water temperatures of 24–25 C; Bybee et al 2007).…”

Fan worms (Annelida: Sabellidae) from Indonesia collected by the Snellius II Expedition (1984) with descriptions of three new species and tube microstructure

“…19951]. However, S. spectabilis from Hawaii is a protandric hermaphrodite (Bybee, Bailey-Brock & Tamaru, 2006), while the same species is reported to be gonochoric in Micronesia (Rouse & Fitzhugh, 1994). This indicates that more than one species may be included under the same name.…”