ecological effects of marine protected areas empafish project ...

EMPAFISH Booklet no. 1 Ecological effects of Atlanto-Mediterranean MPAs in the EU
The population of the MPA did not reveal any genetic differentiation compared
to surrounding areas (Lenfant 1998). Comparing D. sargus genetic structure
within Cerbère/Banyuls with unprotected sites, and with other MPAs –
including other EMPAFISH case studies, such as Cabo de Palos and Tuscany
archipelago, as well as control, unprotected sites (González Wangüemert et
al. 2002, 2004; Pérez Ruzafa et al. 2006), it is observed that protected areas
show significant higher allelic richness than unprotected sites. In parallel,
islands showed lower level of heterozygosis and higher heterozygote deficit
compared with coastal areas, making clear the importance of considering the
connectivity processes when designing an MPA.
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o Benthic assemblage
The abundance and size structure of sea urchins (Paracentrotus lividus) have
been compared between partial reserve and unprotected areas (Laspougeas
1994; Skaki 1997; Lecchini 1999) in relation with the fishing pressure (Binche
1987). Density of edible sea urchins (P. lividus) was three times higher within
the marine reserve together with an average larger size inside the MPA.
Similar approach was also undertaken for Mytilus galloprovincalis (Jacquet
1999) considering both the MPA effect together with the location and the
accessibility. The result shows a larger size of individuals in the MPA, but the
distribution is extremely biased by the accessibility of the mussels.
� Fish movement (including spillover)
A preliminary work was targeted into the determination of a biomass gradient
through the MPA limits (Garcia-Charton & Planes 2002) considering the
variability in the substratum. The result demonstrated a significant gradient in
the southern areas and not in the northern, suggesting some export of
biomass from the MPA. Within the CE project BIOMEX (http://biomex.univperp.fr),
studies have been undertaken to test the hypothesis that spillover
from MPAs to neighbouring areas should have as consequence the observation
of gradients of fish biomass across boundaries. In Cerbère/Banyuls, this
hypothesis is going to be tested by using UVC, baited video, collection of fish
eggs and larvae by plankton nets, and experimental fishing as sampling
techniques, following a sampling design including several sites inside the MPA
plus other sites outside the MPA (to the North, and to the South). Results of
these studies are being analysed at present.
Tele-acoustic works are under development presently to investigate
movement of grouper and sparidae, across the MPA boundaries.
� Effects on habitat (including impact of divers)
The MPA of Cerbère/Banyuls receives ca. 25,000 divers per year, this activity
concentrating mostly in summer, and principally in 2 diving spots. Impact of
divers on benthos are under survey by comparing, each year, the density of a
series of benthic species selected as indicators (algae, sponges, cnidarians,
echinoderms, bryozoans, polychaetes and ascidians) just before and after