Fauna asociada a la nacra <i>Pinna nobilis</i> (Mollusca: Bivalvia) en la costa norte y este de Túnez

Abstract

SUmmARy: epifaunal communities associated with the fan shell Pinna nobilis Linnaeus, 1758 along the tunisian coastline were investigated. Both univariate and multivariate analysis were done at different spatial scales within five populations located at different localities, three from northern and two from eastern tunisia. the size of Pinna did not appear as the main factor affecting the structure of the associated biota, which seemed to be more influenced by (a) marine-lagoon and (b) biogeographic gradients. Patterns of similarity of sessile sclerobionts and motile epifauna were clearly different. the former assemblage best replied to lagoon-sea gradient and to locality, with three real clusters at 40%, whereas the latter assemblage scattered widely in a non-metrical mdS plane, with two real clusters only at 20% similarity. the spatial turnover of motile species was ten times higher than that of sessile species at a small spatial scale, being less affected by Pinna size, and three times higher though invariant at a large geographic scale. on the other hand, β-diversity of sessile species appeared to be more influenced by latitudinal (climatic) gradient at a large scale, being higher in the northern than in the eastern communities. Analysis of taxonomic (dis)similarity of the whole community detected these two sources of environmental (lagoon-sea gradient) and biogeographic (lati-longitudinal gradient) variation, although each phylum showed its peculiar pattern. in terms of dajoz's constancy index the majority of associated communities were dominated by rare species, and within the majority of epifaunal assemblages, the most abundant sessile epizoobiont was a bivalve mollusc. the sessile epifauna was dominated by active filterers, which led to a possible existence of trophic competition between the host and the sedentary epizoites, since both basibionts and sclerobionts occupy the same trophic niche. the fan shell played an important ecological role, providing new hard substrate to colonise, increasing the spatial heterogeneity for the surrounding softbottom communities, and contributing to the overall increase of the local biotope complexity level.Keywords: Pinna nobilis, epifauna, assemblages, β-diversity, spatial scale, tunisian coasts.ReSUmen: Fauna asociada a la nacra Pinna nobilis (Mollusca: Bivalvia) en la costa norte y este de Túnez. -Se investigaron las comunidades de la epifauna asociadas a la nacra Pinna nobilis Linnaeus, 1758 a lo largo de la costa de túnez. Se realizaron análisis univariantes y multivariantes a diferentes escalas espaciales en cinco poblaciones situadas en diferentes localidades, tres del norte y dos del este de túnez. La talla de Pinna nobilis no fue el factor que más afectó la estructura de los organismos asociados, que parecieron más influenciados por (a) lagunas marinas y (b) gradientes biogeográficos. Los patrones de similaridad de los esclerobiontes sésiles y la epifauna móvil fueron claramente distintos. La primera asociación respondió mejor al gradiente laguna-mar así como a...

Current Status of Critically Endangered Fan Mussel Pinna nobilis (Linnaeus 1758) Population in Çanakkale Strait, Turkey

“…Due to this characteristic, it is a good and sensitive bio-indicator for Mediterranean littoral quality and water quality (Vicente et al, 2002;Natalotto et al, 2015). In addition to the hard surface of this species, it serves as potential living habitat for many species such as annelids, ascidians, bivalves, bryozoans, cnidarians, crustaceans, echinoderms, macroalgae, gastropods, sponges (Rabaoui et al, 2009, Acarli et al, 2010. On the other hand, the population of ecologically important fan mussel has been greatly reduced due to recreational and commercial fishing activities to supply food, shell usage for decorative purposes, and incidental killing by trawling and/or anchoring.…”

From Dark to Light and Back Again: Is Pinna Nobilis, the Largest Mediterranean Bivalve, on the Brink of Extinction?

“…Fig. 2), which can be colonized by hard-bottom benthic species, such as algae, sponges, mollusks (including other bivalves), and polychaetes (Corriero and Pronzato, 1987;Giacobbe, 2002;Addis et al, 2009, Rabaoui et al, 2009. Remarkably, this species hosts the crustaceans Pontonia pinnophylax and Nepinnotheres pinnotheres (Rabaoui et al, 2008).…”

Trophic role of marbled crayfish in a lentic freshwater ecosystem

“…It typically thrives in seagrass meadows, such as Posidonia oceanica, Cymodocea nodosa, Zostera marina, and Z. noltii (Prado et al 2014) but also in macroalgal beds (Katsanevakis and Thessalou-Legaki 2009), unvegetated sandy habitats (Katsanevakis 2006), estuarine areas (Addis et al 2009), and even in small sandy patches within predominantly rocky habitats (Tsatiris et al 2018). It plays a key ecological role by filtering water and retaining large amounts of organic matter from suspended detritus, thus reducing turbidity (Trigos et al 2014), providing hard substrate colonized by numerous epibionts in soft-bottom habitats (Addis et al 2009;Rabaoui et al 2009), and, at high densities, acting as an ecosystem engineer able to create biogenic reefs (Katsanevakis 2016).…”