Page 2 - Preprint_2014

45° Congresso della Società Italiana di Biologia Marina
Venezia, 19-23 maggio 2014
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V. CIANCIMINO, M. MILAZZO, R. CHEMELLO

Dipartimento di Scienze della Terra e del Mare (Di.S.Te.M.), Università di Palermo,
Via Archirafi, 28 – 90123 Palermo, Italia.
velia_ciancimino@hotmail.it

EFFECTS OF HUMAN HARVESTING ON PATELLA ULYSSIPONENSIS
GMELIN, 1791 POPULATIONS

EFFETTI DEL PRELIEVO UMANO SU POPOLAZIONI DI PATELLA
ULYSSIPONENSIS GMELIN, 1791

Abstract - An analysis on Patella ulyssiponensis populations in northwestern Sicily was made in order to
highlight potential effects of human harvesting. Our data highlight a reduction in density and population
structure well related to the increase of coastal frequentation by humans.

Key-words: abundance, harvesting, intertidal, Patella ulyssiponensis, Mediterranean Sea

Introduction - The majority of the human population lives in the coastal zone,
impacting in different ways on it. Highly diverse benthic assemblages characterize the
rocky intertidal shore and humans have exploited them for centuries. Patellid limpets
are sessile invertebrate of the rocky intertidal, the exploitation of which is very
common all over the world. They are harvested as food, at both commercial and
recreational levels, or as bait (Martins et al., 2008).
Limpet’s harvesting by humans is a very common activity along the Sicilian coasts,
being more frequent from June to September, when larger specimens are usually
collected. The degree of harvesting could be affected by the accessibility (e.g. the
distance between a road and the coast), but coastal protection could be theoretically
important to avoid exploitation.
Being limpets proterandric hermaphrodite species, their size-selective exploitation
likely causes major consequences on population structure at local scale (McCarthy et
al., 2008). Larval recruitment of Patella ulyssiponensis occurs in Autumn, young
individuals develop male gonads during Winter, while in Spring around the 70% of the
population becomes female, increasing in size (Thompson, 1979). Here we evaluated
the distribution of Patella ulyssiponensis populations along the northwestern coast of
Sicily affected by seasonal harvesting, according to site accessibility and protection.
Materials and methods - This study was conducted from July to August 2012 in 11
localities, from Petrosino (TP) to Addaura (PA) and in Favignana (Egadi Islands,
Italy). Two sites, separated by almost 100 m, were chosen for each locality and the
sampling was carried out by counting all the specimens within five plots (20x20 cm
each) randomly placed on intertidal rocky platforms, and measuring on field, to avoid
collection of organisms, their maximum diameter. Six ranks of accessibility were
defined combining the distance of the coastline from a road (e.g. high accessibility, less
than 50 m; medium accessibility, from 50 to 100 m; low accessibility more than 100
m) with the presence of coastal protection (high accessibility, no protection; low
accessibility, protected). Limpets were divided into three size classes: from 0 to 6 mm,
from 6.1 to 18 mm, and more than 18.1 mm.

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