Preprint volume - SIBM

Pre-print Volume - Posters
BENTHOS COMMITEE
S. CARONNI, A. NAVONE *
Dip.to di Ecologia del Territorio, Sezione di Ecologia, Via S.Epifanio, 14 - 27100 Pavia, Italia.
sarah.caronni@unipv.it
* Area Marina Protetta di Tavolara-Punta Coda Cavallo, Olbia, Italia.
DENSITY AND SIZE OF THE FAN MUSSEL PINNA NOBILIS
(LINNEO, 1758) IN TWO DIFFERENTLY PROTECTED ZONES
OF TAVOLARA-PUNTA CODA CAVALLO MARINE PROTECTED AREA
DENSITÀ E TAGLIA DEL BIVALVE PINNA NOBILIS
(LINNEO, 1758) IN DUE ZONE DIVERSAMENTE PROTETTE
DELL’AMP DI TAVOLARA-PUNTA CODA CAVALLO
Abstract – In the summer months of 2009 the abundance and the total shell size of the endangered bivalve
Pinna nobilis (Linneus, 1758) (Mollusca: Bivalvia) were investigated in a partial reserve zone and in a
general reserve one of the marine protected area of Tavolara-Punta Coda Cavallo (N-E Sardinia) in order
to assess the usefulness of stricter environmental protection.
Key-words: environmental protection, marine parks, rare species, marine molluscs, density.
Introduction – During the last decades the population of Pinna nobilis (Linneo, 1758),
the largest Mediterranean bivalve, has been consistently declining (Vicente and
Moreteau, 1991) as a result of collection by divers (Zavodnik et al., 1991) and
incidental killing by trawling and anchoring (Centoducati et al., 2007). Consequently
this fan mussel has been listed as an endangered species and is nowadays under
protection, according to the European Council Directive 92/43/EEC. The aim of this
work is to improve the knowledge on the distribution of P. nobilis in the Tavolara-
Punta Coda Cavallo Marine Protected Area and to verify if stricter protection rules
positively affect the density and the size of this species.
Materials and methods – Two areas of approximately 500 m 2 near Molara and
Isolotto Rosso islands, situated respectively in a partial reserve zone (B) and in a
general reserve (C) one, were chosen for the study because of substrate similarities. In
each site a 100 m long transect line was drown from the shore perpendicularly to the
shoreline (Šiletić and Peharda, 2003) and all bivalves in two 2,50 m corridors on either
side of the transect line were recorded. For each specimen the unburied length and the
width at sediment level were measured with a multi-calliper similar to the one
proposed by García-March et al. (2002) and total shell lengths were estimated with
García-March and Ferrer’s equation (1995). Statistical analyses (MINITAB Student
Release 12) allow the comparison between the recorded specimens in the two sites.
Results – In both study sites P. nobilis specimens were found on sandy and cobbled
substrates, in particular among sea grass Posidonia oceanica (L.) Delile patches. In the
summer months of 2009, 29 bivalves were totally counted in the study area; 11 along
the transect near Isolotto Rosso island (RI) and 18 along the one near Molara island
(MI). Data about density and total shell length of specimens along the two transects are
shown in Tab. 1.
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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