Distribution, abundance and ecology of the sponge Spheciospongia vagabunda (Phylum: Porifera, Class: Demospongiae) in a shallow lagoon of Mauritius.

Le résumé fourni par la source

The distribution, abundance and physico-chemical parameters affecting the sponge Spheciospongia vagabunda were studied in a shallow lagoon (Albion) of Mauritius.  Visual censuses were conducted along the 2 Km lagoon and GPS coordinates around sponge assemblages (patches) were noted.  Sponge abundance and ecological parameters were assessed by random throws of quadrats and physico-chemical parameters, including water depth; salinity, pH, and turbidity were noted.   A distribution map of Spheciospongia vagabunda was constructed on Google Earth.  Two distinctive sponge patches with the largest patch averaging 15350 m 2 were identified.  Spheciospongia vagabunda in Albion were mostly anchored in the sand which is an unlikely substratum for Poriferans.  Some sponges were also observed next to the seagrass Syringodium filiforme .  Statistical analysis (t-test) showed that there was a significant difference among sponge size between both sponge assemblages (t = 3.01; p < 0.05).  One-way ANOVA analysis indicated that physico-chemical parameters of surrounding water did not influence the sponge abundance within the lagoon.  Spheciospongia vagabunda were mostly distributed in shallow regions (3.3 sponge/m 2 at a depth of 1.18 m).  This study adds to the lack of knowledge on Mauritian sponges and also acts as a baseline study for further monitoring of these benthic animals in the Albion lagoon.

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