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The effectiveness of marine protected areas (MPAs) and the conservation of marine environments must be based on reliable information on the quality of the marine environment that can be obtained in a reasonable timeframe. We reviewed studies that evaluated all aspects related to the effectiveness of MPAs in order to describe how the studies were conducted and to detect fields in which research is lacking. Existing parameters used to evaluate the effectiveness of MPAs are summarised. Two-hundred and twenty-two publications were reviewed. We identified the most commonly used study subjects and methodological approaches. Most of the studies concentrated on biological parameters. Peer reviewed studies were based on control vs. impact design. BACI and mBACI designs were used in very few studies. Through this review, we have identified gaps in the objectives assigned to MPAs and the way in which they have been evaluated. We suggest some guidelines aimedat improving the assessment of the effects of protection in MPAs.

In the present study the fish assemblages in the rocky-bottom habitat of the Sierra Helada Natural Park (Alicante, Spain) were recorded to provide data for future evaluation of any changes induced by long-term management. Visual censuses were carried out along strip transects by Scuba diving on rocky bottoms at depths between 1 and 32 m. In the seven localities sampled, 44 species were recorded. Number of species, abundance, biomass and size structure values recorded did not show differences between high and low protection areas. Species composition was similar to other marine protected areas of the western-Mediterranean. The main differences found between localities can be attributed to the high heterogeneity and complexity of the habitat at smaller spatial scales.

The article presents a study which offers evidence of whether sea bass escapees are short- or long-lived and to assess the feeding habits of externally-tagged sea bass recaptured by local fishermen in the Mediterranean Sea. The application of the tagging method in which the fishermen were provided with the fish information is cited. It is inferred that the presence of particulate organic matters in the stomachs indicate the aggressive feeding behaviour of escaped sea bass.

The present study compares fin damages in gilthead seabream ( Sparus aurata) and European seabass ( Dicentrarchus labrax) according to their wild, escaped or farmed origins. In addition, the potential applicability of fin condition indices (Fin Erosion Index ' FEI' and Fin Splitting Index ' FSI') as identification tools is discussed. Farmed seabream fins evidenced more erosion and splitting ( FEI ± SD: 2.1 ± 0.3; FSI ± SD: 1.9 ± 0.6) than wild seabream fins ( FEI: 0.8 ± 0.6; FSI: 1.2 ± 0.9), a result of farming conditions in open-sea cages. Escaped seabream fin erosion was between that of farmed and wild seabream ( FEI: 1.6 ± 0.4), which could indicate that fins in farmed fish recover over time from farming abrasions once they are in the wild. However, the fins of escaped seabream seem to be weaker than those of the wild fish, and therefore might be more susceptible to suffer other types of erosion such as splitting or nipping ( FSI: 2.3 ± 0.7). No significant differences were found in seabass FEI according to their origins, although wild seabass presented significantly more split caudal fins ( FSI: 3.3 ± 2.8) than the farmed seabass ( FSI: 1.2 ± 1.1) and escapees ( FSI: 2.5 ± 1.6). Therefore, FEI for seabream could be used as tools not only to distinguish between wild and farmed fish, but also to identify recent escapees, improving further assessments on the contribution of seabream escapees in fishery landings. However, the healing potential of damaged fins must be considered for the proper identification of escapees. Use of fin condition indices from both species could be helpful for aquaculture management, to assess fish welfare in fish farms stocks, and improve the knowledge of handling, stock densities and open-sea cage environment conditions. [ABSTRACT FROM AUTHOR]

This study describes the changes in the structure of the fish assemblage associated with Posidonia oceanica meadows after the establishment of a marine protected area. The survey of the ichthyofauna in the Marine Reserve of Tabarca Island was carried out by visual censuses with SCUBA. Inside and outside the reserve was sampled six times at random from summer 1997 to summer 1999 and in three different depths (1, 5 and 15 m) by applying transects of 150 × 5 m over the P. oceanica meadows. The data were analyzed with multivariant methodologies and with analysis of variance. The most represented families in number of species were the sparids and labrids. Mean abundance, biomass and number of species were higher inside the reserve in all studied periods. Inside the marine protected area, these variables decreased as depth increased; outside the protected area the pattern was the opposite, reaching the maximum at 15 m. [ABSTRACT FROM AUTHOR]

Ichthyoplankton associated with P. oceanica meadows during the summer season in the Tabarca marine reserveHabitat complexity plays a key role in survival in early stages of fish larvae. We investigated fish larvae assemblage and its relation with P. oceanicaseagrass at the Tabarca Island Marine Reserve. Samples were taken using moored plankton nets at two depths (0 and 2 m from P. oceanica meadow) over five consecutive days in July 2000. Three hundred and fifty¿three larvae were captured. The mostabundant families were Clupeidae (31%), Sparidae (27%), Engraulidae (11%) and Gobiidae (6%). We observed that small fish larvae were able to select nursery areas. We conclude that the P. oceanica leaf canopy is a major factor in structuring the larval fish assemblages of some demersal species.

The effects of the invasive species Caulerpa racemosa var. cylindracea (hereafter C. racemosa) on amphipod assemblages associated with shallow-water rocky habitats were studied. Two habitats located along the SE Iberian Peninsula were compared; invaded and non-invaded. The results showed that growth of C. racemosa affects habitat structure, influencing the species composition and biomass of macroalgae, and detritus accumulation. In turn, such changes in habitat features affected the associated amphipod assemblages with different ecological requirements. However, the species richness of amphipods was relatively high in both habitats, while the species composition of amphipods changed completely. For example, some species such as Ampithoe ramondi and Hyale schmidti did not colonize invaded habitats, while others such as Apocorophium acutum were favoured by the spread of C. racemosa. Habitat invasion by C. racemosa can have an important influence on biotic assemblages, modifying both habitat structure and the associated fauna, with unknown effects on the overall ecosystem.