Several studies have assessed the effectiveness of individual marine protected areas (MPAs) in protecting fish assemblages, but regional assessments of multiple parks are scarce. Here fish surveys using visual census were done in marine parks and fished areas at 31 locations across

the Mediterranean Sea. Fish species richness, diversity and biomass (especially of top predators) were higher in MPAs compared to fished areas, and community structure differed significantly between MPAs and fished areas. Results suggest that MPAs are generally effective means to protect and recover fish populations and assemblages

Ballesteros, Enric

Di Franco, Antonio

Guidetti, Paolo

Hereu, B.

MacPherson, Enrique

Micheli, Fiorenza

Pais, Antonio

Panzalis, Pier Augusto

Rosenberg, A.

Sala, E.

Zabala, Mikel

English

UnissResearch

Biol. Mar. Mediterr. (2010), 17 (1): 39-42
P. GUIDETTI1, E. SALA2, 3, E. BALLESTEROS3, A. DI FRANCO1, B. HEREU, E. MACPHERSON3, 
F. MICHELI5, A. PAIS6, P. PANZALIS7, A. ROSENBERG8, M. ZABALA4
1CoNISMa and DiSTeBA, University of Salento, Lecce, Italy. 
paolo.guidetti@unisalento.it
2National Geographic Society, P.O. Box 98199, Washington, DC, USA.
3Centre d’Estudis Avançats de Blanes, CSIC, Accés Cala Sant Francesc, 14 - 17300 Blanes, Girona, Spain.
4Department of Ecology, University of Barcelona, Diagonal 645 - 08028 Barcelona, Spain.
5Hopkins Marine Station, Stanford University, Oceanview Boulevard, Pacific Grove, CA 93950-3094, USA.
6Sez. di Acquacoltura e Gestione delle Risorse Acquatiche, Dip. Scienze Zootecniche, 
Università di Sassari, Italy.
7Marine Protected Area of Tavolara-Punta Coda Cavallo, Via Dante, 1 - 07026 Olbia, Italy.
8Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 
03824, USA.
FISH ASSEMBLAGES ACROSS THE MEDITERRANEAN SEA 
AND THE EFFECTS OF PROTECTION FROM FISHING
I POPOLAMENTI ITTICI NEL MEDITERRANEO 
E GLI EFFETTI DELLA PROTEZIONE DALL’IMPATTO DELLA PESCA
Abstract – Several studies have assessed the effectiveness of individual marine protected areas 
(MPAs) in protecting fish assemblages, but regional assessments of multiple parks are scarce. Here 
fish surveys using visual census were done in marine parks and fished areas at 31 locations across 
the Mediterranean Sea. Fish species richness, diversity and biomass (especially of top predators) were 
higher in MPAs compared to fished areas, and community structure differed significantly between MPAs 
and fished areas. Results suggest that MPAs are generally effective means to protect and recover fish 
populations and assemblages.
Key-words: fish biomass, predators, marine parks, fishing impact, visual census, Mediterranean Sea.
Introduction – Marine protected areas (MPAs) are portions of the coastline and/
or sea where human activities, especially fishing, are restricted or banned (Agardy et 
al., 2003). As fish assemblages usually include many species targeted by fishing, they 
are primarily expected to respond to protection within MPAs, especially those MPAs 
that have no-take zones (Micheli et al., 2004). The evaluation of benefits on fish 
assemblages, e.g. in terms of increase in density, size and biomass of target fishes 
(Micheli et al., 2004; Guidetti & Sala, 2007), can be useful to assess the ecological 
effectiveness of MPAs. Moreover, most target fishes are high-level predators in the 
food webs and their functional extinction may cause community-wide changes (Sala 
et al., 1998; Worm et al., 2006). Protection from fishing, therefore, may directly 
restore populations of target fishes and indirectly drive whole communities towards 
an unfished state (Sala et al., 1998; Micheli et al., 2004). Effective MPAs and, more 
generally, areas characterized by null/low levels of exploitation were found worldwide 
to host particularly high total fish biomass with a clear dominance of top predators 
(Friedlander & DeMartini, 2002). In the Mediterranean Sea, approximately 100 
MPAs have been established (Abdulla et al., 2008), making this region among those 
with the highest concentration of MPAs in the world. A number of Mediterranean 
studies assessed direct and indirect ‘reserve effects’ of protection (Guidetti & Sala, 
2007 and references therein). Most of the ‘reserve effect’ assessment studies in the 
Mediterranean basin were carried out focusing on fish assemblages associated with 
rocky reefs, due to the fact that: 1) rocky reefs are the most common habitat protected 
within MPAs in Mediterranean; 2) previous visual census studies showed that 
rocky reefs host greater abundance of fish species targeted by fishing and that fish 
assemblages more clearly respond to protection from fishing than others (e.g., benthic 
P. GUIDETTI ET AL.40
assemblages). This study aims at investigating the generality of responses to protection 
of fish assemblages associated with shallow rocky reefs across the Mediterranean 
Sea, by comparing MPAs and areas open to fishing and other human uses.
Materials and methods – Fish surveys were done in late spring 2007 and 2008 at 
12 MPAs and 19 fished areas across the northern Mediterranean coast (Spain, Italy, 
Greece, Turkey; Fig. 1).
Fig. 1 -  Location of Marine Protected Areas and fished areas investigated in this study.
Localizzazione delle Aree Marine Protette ed aree aperte alla pesca oggetto del presente studio.
Fish data were collected by using underwater visual census (UVC) at several 
stations within each areas (protected or fished), with three replicated UVCs at each 
station, for a total of 516 UCVs. Each replicate consisted of a 25 m-long and 5 m-wide 
transect. Along each transect, the diver swam one way (at ~10 m depth) for about 
8-10 min, identifying and recording the number and size of each fish encountered 
(Harmelin-Vivien et al., 1985). Fish wet-weight was estimated from size data by means 
of length-weight relationships from the available literature and existing databases 
(Froese & Pauly, 2009). Multivariate and univariate analyses were conducted to 
examine whether fish assemblage structure (i.e. taxa composition and abundances) 
and single variables (e.g. species richness) responded to protection. Effects of 
protection were analyzed on whole fish assemblages (using species×sample matrices) 
using three-way permutational multivariate analysis of variance (PERMANOVA) 
both on abundance and biomass data. The sampling design consisted of 3 factors: 
Protection (Pr; fixed factor with 2 levels), Area (Ar; random and orthogonal) and 
Station (St; random and nested in Area). Multivariate analyses were based on Bray-
Curtis dissimilarity matrices and ln(x+1) transformed data. Univariate analyses on 
species richness, diversity, and total abundance and biomass of fish were run using 
t-tests to compare mean values under protected and unprotected conditions. Finally, 
fish taxa in terms of biomass data from both protected and fished conditions 
were pooled into trophic groups because fishing disproportionately targets species 
at higher trophic levels (Pauly et al., 1998), and recovery from fishing potentially 
includes increased abundances or biomass of high-level predators and shifts in 
trophic structure (Micheli et al., 2004). Each taxon was assigned to one of 4 trophic 
macrogroups using the information about diet in the database “FishBase” (Froese 
& Pauly, 2009), and in Mediterranean studies (Guidetti & Sala, 2007): 1) large 
apex predators (large carnivores, AP), 2) small carnivores (including piscivores and 
invertivores, SC), 3) herbivores (He), and 4) planktivores-detritivores (PD).
Results – Multivariate analyses (PERMANOVA tests) showed that considering 
total fish abundance (P<0.01) and even more biomass (P<0.001), fish assemblage 
Fish assemblages across the Mediterranean Sea and the effects of protection from fishing 41
structures were significantly different between MPAs and fished areas, and that 
a significant variability was detected at both spatial scales of areas and stations. 
Species richness (t-tests, P<0.01), diversity (t-tests, P<0.05) and total biomass of fish 
(t-tests, P<0.01) were significantly higher in protected than in fished conditions, 
while no statistical differences were found as far as fish abundance (t-tests, P>0.05) 
was concerned. In spite of a significant variability among areas (especially among 
MPAs), total fish biomass clearly tended to be higher in MPAs (Fig. 2).
Fig. 2 - Total fish biomass in Marine Protected Areas and fished areas investigated in this study.
Biomassa ittica totale nelle Aree Marine Protette ed aree aperte alla pesca oggetto del presente studio.
Fish biomass split into the 4 trophic groups (see Methods) was different between 
MPAs and fished areas. At MPAs, in fact, predator fishes, especially apex predators 
(18.4 vs 5.5%), were far better represented than in fished areas (Fig. 3). 
Fig. 3 -  Fish biomass of different trophic groups (see Methods) in Marine Protected Areas and 
fished areas investigated in this study.
Biomassa ittica dei quattro differenti gruppi trofici (vedi Metodi) nelle Aree Marine Protette ed aree 
aperte alla pesca oggetto del presente studio.
Conclusions – The present study investigated the effects of protection by 
surveying fish assemblages across the Mediterranean scale. In spite of the large site-
to-site variability, fish assemblage structures were found to be significantly different 
between MPAs and fished areas. Moreover, species richness and diversity were 
P. GUIDETTI ET AL.42
greater in MPAs than in fished areas. The greatest differences, however, concerned 
fish biomass. Not only on the whole mean fish biomass was higher in MPAs than in 
fished areas, but in some MPAs the values were dramatically high. In addition, in 
MPAs a significantly greater contribution to the total fish biomass was attributable 
to apex predators. These results are in agreement with the available literature from 
the Mediterranean Sea and elsewhere (Friedlander & DeMartini, 2002; Sandin et al., 
2008) and stress how effective can be MPAs for recovery of fish at population and 
ecosystem levels.
References
ABDULLA A., GOMEI M., MAISON E., PIANTE C. (2008) - Status of Marine Protected Areas 
in the Mediterranean Sea. IUCN, Malaga and WWF, France: 152 pp.
AGARDY T., BRIDGEWATER P., CROSBY M.P., DAY J., DAYTON P.K., KENCHINGTON R., 
LAFFOLLEY D., MCCONNEY P., MURRAY P.A., PARKS J.E., PEAU L. (2003) - Dangerous 
targets? Unresolved issues and ideological clashes around marine protected areas. Aquat. Cons.: 
Mar. Freshwater Ecosyst., 13: 353-367.
FRIEDLANDER A.M., DEMARTINI E.E. (2002) - Contrasts in density, size, and biomass of reef 
fishes between the northwestern and the main Hawaiian islands: the effects of fishing down 
apex predators. Mar. Ecol. Prog. Ser., 230: 253-264.
FROESE R., PAULY D. (2009) - Fish Base. World Wide Web electronic publication, www.fishbase.
org
GUIDETTI P., SALA E. (2007) - Community-wide effects of marine reserves. Mar. Ecol. Prog. 
Ser., 335: 43-56.
HARMELIN-VIVIEN M.L., HARMELIN J.G., CHAUVET C., DUVAL C., GALZIN R., 
LEJEUNE P., BARNABE G., BLANC F., CHEVALIER R., DUCLERC J., LASSERRE G. 
(1985) - Evaluation des peuplements et populations de poissons. Méthodes et problemes. Rev. 
Ecol., 40: 467-539.
MICHELI F., HALPERN B.S., BOTSFORD L.W., WARNER R.R. (2004) - Trajectories and 
correlates of community change in no-take marine reserves. Ecol. Appl., 14: 1709-1723.
PAULY D., CHRISTENSEN V., DALSGAARD J., FROESE R., TORRES F. JR. (1998) - Fishing 
down marine food webs. Science, 279: 860-863.
SALA E., BOUDOURESQUE C.F., HARMELIN-VIVIEN M.L. (1998) - Fishing, trophic cascades, 
and the structure of algal assemblages: evaluation of an old but untested paradigm. Oikos, 82: 
425-439.
SANDIN S.A., SMITH J.E., DEMARTINI E.E., DINSDALE E.A., DONNER S.D., 
FRIEDLANDER A.M., KONOTCHICK T., MALAY M., MARAGOS J.E., OBURA D., 
PANTOS O., PAULAY G., RICHIE M., ROHWER F., SCHROEDER R.E., WALSH S., 
JACKSON J.B.C., KNOWLTON N., SALA E. (2008) - Baselines and Degradation of Coral 
Reefs in the Northern Line Islands. PLoS ONE, 3 (2): e1548. doi:10.1371/journal.pone.0001548
WORM B., BARBIER E.B., BEAUMONT N., DUFFY J.E., FOLKE C., HALPERN B.S., 
JACKSON J.B., LOTZE H.K., MICHELI F., PALUMBI S.R., SALA E., SELKOE K.A., 
STACHOWICZ J.J., WATSON R. (2006) - Impacts of biodiversity loss on ocean ecosystem 
services. Science, 314: 787-790.
This work was supported by grants from the Oak Foundation and the Pew Charitable Trust.


Fish assemblages across the Mediterranean Sea and the effects of protection from fishing = I Popolamenti ittici nel Mediterraneo e gli effetti della protezione dall’impatto della pesca

Fish assemblages across the Mediterranean Sea and the effects of protection from fishing = I Popolamenti ittici nel Mediterraneo e gli effetti della protezione dall’impatto della pesca

Abstract

Similar works

Full text

Available Versions

UnissResearch