Reproduction of the Intertidal Sponge Hymeniacidon perlevis (Montagu)Along a Bathymetric Gradient

Abstract

Abstract:The reproductive cycle of the demosponge Hymeniacidon perlevis (Montagu) was investigated at the Mar Piccolo di Taranto (Ionian Sea, Apulian). According to the distribution of the specimens, along a bathymetric gradient, sponges have been subdivided in two groups, named group A and group B. The former was made up of specimens that are usually exposed in the air when there is a low water level and the latter by specimens that are constantly submerged. Monthly monitoring (February 2006 -January 2007 of twenty tagged specimens (ten in each group) was carried out in order to compare the reproductive efforts in the two groups. The reproductive pattern differed slightly between the two groups; the majority of the females in group B restrict oocyte production till May. In addition, group A exhibits a significantly higher density of sexual elements, than those belonging to group B. It was hypothesised that the sexual activity of the submerged specimens, living close to the soft bottom, could be influenced by severe anoxic crises due to periodic algal decay, whereas the intertidal specimens, located some decimetres off the soft bottom, and subjected to the moderate water movement, were not affected. The thick algal assemblage associated with the intertidal specimens gives protection against dehydration and solar irradiation during the prolonged periods of air exposure. By September, none of the monitored specimens had survived. The finding of newly developing small specimens in late winter supports a possible colonisation from residual sponge fragments dispersed before mass mortality.

Sexual reproduction in Sarcotragus spinosulus from two different shallow environments

“…Asynchronous spermatogenesis at the individual level may increase the chances of fertilization, because mature oocytes are available over several months . A relatively asynchronous spermatogenesis has been reported for the Dictyoceratida Rhopaloeides odorabile Thompson, Murphy, Bergquist & Evans, 1987(Whalan et al 2007a Wahab et al, 2012) and for other demosponges (L evi 1956;Chen 1976;Gaino et al 1986;Mercurio et al 2007;Riesgo 2007;Gaino et al 2010).…”

“…The presence of two groups of sponges belonging to the same species living in these two different shallow environments gave us the opportunity to study the reproductive cycle of 20 tagged specimens of S. spinosulus over 1 year, to evaluate possible differences related to the environmental conditions in the two sites, with particular attention to the different thermal regime (Corriero 1990;Baldacconi et al 2007;Mercurio et al 2007). Porifera, are in fact heterotherms, and seawater temperature plays a pivotal role in their reproductive activity (Diaz 1973;Fromont and Berquist 1994;Witte et al 1994;Corriero et al 1998;Fromont 1999;Ereskovsky 2000;Usher et al 2004;Ettinger-Epstein et al 2007;Mercurio et al 2007;Gaino et al 2010;Piscitelli et al 2011;Di Camillo et al 2012).…”

Abundance, distribution and habitat preference of Hippocampus guttulatus and Hippocampus hippocampus in a semi‐enclosed central Mediterranean marine area

“…; Gaino et al . ). Moreover, the anoxia phenomenon seems to prevent the seasonal migration into deeper water (>10 m) described by Boisseau () in cooler waters for both H. hippocampus and H. guttulatus (Corriero pers.…”

Unusual Symbiotic Cyanobacteria Association in the Genetically Diverse Intertidal Marine Sponge Hymeniacidon perlevis (Demospongiae, Halichondrida)

“…perlevis in a relatively restricted geographic range (∼500 Km) (ATP6, π = 0.00177; COI, π = 0.00241; and SP1, π = 0.00277) (Table 1) revealing considerable variability in this intertidal sponge species. Genetic richness of the studied H. perlevis sponge further suggests the involvement of sexual reproduction and pelagic larval dispersal [57], [58]. Considering the geographical distance of the sampling locations from North to South of Portugal (∼500 Km), we believe that environmental factors and reduced larval mobility [59] may be influencing the genetic makeup [60] of the intertidal marine sponge H .…”