[Show abstract][Hide abstract] ABSTRACT: Mullet, hake, lobster and shrimp are the main métiers in western Mediterranean trawl fishery.•Management of multi-specific fisheries should start off considering métiers characteristics.•Effort distribution among métiers can indicate suitable time to reduce effort on target species.•Controlling fleet capacity could be more effective when done by métier.
[Show abstract][Hide abstract] ABSTRACT: Recreational diving effects on Mediterranean benthic communities have been scarcely studied to date. In this study, we evaluate the recreational diving impact on the Mediterranean bryozoan Myriapora truncata. Eight localities with different diving rates and protection levels were sampled before and after summer, the season of maximum presence of divers in the region. A photographic sampling technique was used, which made possible to increase the number of replicates. In each sample: number; mean, maximum and total area; total and mean perimeter and exposure; and aggregation levels of M. truncata colonies were measured by image treatment software. ANOVA, MDS and PERMANOVA were the statistical techniques used to detect and evaluate the effects of the five factors considered (time, protection, impact, locality and site) on M. truncata colonies. The number, area and perimeter of colonies significantly decreased after summer at localities with high presence of divers; whereas hidden colonies went through a positive increase comparing with exposed colonies. Our results evidence M. truncata as a good indicator species for recreational diving impact on coralligenous reef communities. The monitoring of a combination of representative parameters of this species could play an important role on the management of diving areas.
[Show abstract][Hide abstract] ABSTRACT: The change of mesh size or shape as a management measure to improve selectivity as proposed by the EU should be assessed using actual fishery data, despite being tested experimentally in previous studies. This work was conducted to evaluate the consequences of inserting either a 40-mm square-mesh or a 50-mm diamond-mesh (instead of the traditional 40-mm diamond-mesh) at codends in commercial Spanish trawlers. Landings in terms of biomass, income and catch composition were compared under commercial conditions. Four métiers were identified in the fishery: European hake (Merluccius merluccius), red mullet (Mullus barbatus), red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). No significant differences were observed in biomass or income owing to the new mesh in either European hake or red mullet. In contrast, the total biomass of the red shrimp métier and the biomass of the Norway lobster, Nephrops norvegicus, were significantly higher after the selectivity change. Regarding the catch composition, only the European hake métier showed slight – but not significant – changes after using the new mesh. Considering these results, there was no short-term effect (substantial biological or economic loss) as previous studies had expected. This could possibly be related to a higher performance of the new gear that may compensate for the lower retention of small sizes.
Journal of Applied Ichthyology 11/2014; · 0.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta-analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no-take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no-take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no-take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no-take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.
Fish and Fisheries 12/2010; 12(4):412 - 426. · 5.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Marine reserves are assumed to protect a wide range of species from deleterious effects stemming from exploitation. However, some species, due to their ecological characteristics, may not respond positively to protection. Very little is known about the effects of life history and ecological traits (e.g., mobility, growth, and habitat) on responses of fish species to marine reserves. Using 40 data sets from 12 European marine reserves, we show that there is significant variation in the response of different species of fish to protection and that this heterogeneity can be explained, in part, by differences in their traits. Densities of targeted size-classes of commercial species were greater in protected than unprotected areas. This effect of protection increased as the maximum body size of the targeted species increased, and it was greater for species that were not obligate schoolers. However, contrary to previous theoretical findings, even mobile species with wide home ranges benefited from protection: the effect of protection was at least as strong for mobile species as it was for sedentary ones. Noncommercial bycatch and unexploited species rarely responded to protection, and when they did (in the case of unexploited bentho-pelagic species), they exhibited the opposite response: their densities were lower inside reserves. The use of marine reserves for marine conservation and fisheries management implies that they should ensure protection for a wide range of species with different life-history and ecological traits. Our results suggest this is not the case, and instead that effects vary with economic value, body size, habitat, depth range, and schooling behavior.
[Show abstract][Hide abstract] ABSTRACT: The development of transversal competencies provides an integral education. However, its practical implementation among different subjects is not a trivial task. There are several issues that should be previously solved in an optimal way to take advantage of the synergy among subjects. Main issues are: i) the need for a common space for the documents management, ii) the availability of the document everywhere and anytime, and iii) the possibility to collaborate in the documents edition tasks. It was implemented a virtual portfolio for the students which allows the assessment of all the subjects in a global way. To this goal we used the Google apps due to its free access, availability and suitability for the collaborative editing tasks.
International Association for Technology, Education and Development (IATED), Valencia; 01/2010
[Show abstract][Hide abstract] ABSTRACT: Marine protected areas (MPAs) could be useful as fisheries management tools for the exportation of pelagic eggs, larvae and adult fish. A decreasing gradient of fish biomass across MPAs boundary may indicate export. We determine whether gradients of decreasing biomass of fish assemblage occurred in Tabarca Marine Reserve over two habitats with different continuity across the boundaries, to test if the patchy nature of the marine environment might act as a barrier for the fish export. In general, significant decreasing gradients in total fish biomass and biomass of some species were observed on P. oceanica and rocky substrates, independently of their different continuity through the reserve boundaries. Changes in the multivariate structure of the fish assemblage were correlated with the distance from integral reserve. All of these results support the hypothesis that the exportation of adult fish from Tabarca Marine Reserve occurs, and this process may influence the surrounding fished areas.
Marine Environmental Research 12/2008; · 2.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study investigated spillover (biomass export) around 6 marine protected areas (MPAs) in the western Mediterranean based on catch and effort data from artisanal fisheries. The selected MPAs were Cerbere-Banyuls and Carry-le-Rouet in France, and Medes, Cabrera, Tabarca, and Cabo de Palos in Spain. These MPAs had been functional for more than 8 yr and incorporate areas of fisheries closure and restricted use where fishing is limited. We based our study on the hypotheses that, in the presence of biomass export, (1) fishing effort would concentrate close to MPA boundaries, and (2) fishery production, expressed as catch per unit area (CPUA), would be highest near MPA boundaries and decrease with distance. We selected data from 14 'fishing tactics' using gill nets, trammel nets and bottom long-lines targeting sparids, mullids, serranids, scorpaenids and palinurids. We analyzed the spatial distribution of effort, fishery production and revenues per unit area, using generalized additive models (GAMs), and we tested regression slopes of effort density and CPUA with distance to closure boundaries, using generalized linear models (GLMs). GAMs allowed us to recognize habitat discontinuities or 'hot spots' of high production in the vicinity of the MPAs, and to identify the extent of potential spillover effects in order to implement GLMs. We found evidence of effort concentration and high fishery production near fisheries closures for all fishing tactics analyzed and significant negative slopes for most. Revenues generally followed trends similar to CPUA. Significant negative slopes from GLM of effort density and CPUA with distance from fisheries closures were indicative of biomass export where habitats across closure boundaries had some degree of continuity. The spatial extent of spillover was consistent with species mobility and fisheries efficiency and extended 700 to 2500 m from fishery closure boundaries. Our results suggest that coastal MPAs can be an effective management tool for artisanal fisheries in the region and can be extended to the rest of the western Mediterranean, as the fishing tactics studied are typical of the region.
Marine Ecology Progress Series 01/2008; 366:159-174. · 2.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: Marine protected areas (MPA) produce a positive effect on fish populations, but this may be difficult to identify due to the
high temporal variability of populations. Meta-analysis is an option for analysing data from different sources and sampling
designs and it can address problems related to temporal and spatial variability in fish populations. We analysed fish abundance
data from visual counts conducted in summer, from 1996 to 2002, in the MPA of Tabarca (Alicante, Spain). The results showed
an overall positive effect of protection at the species and family levels. Overall abundance of fishes inside the reserve
was, on average, 1.22 times higher than outside the reserve boundaries. Positive effect of protection was found for Boops boops, Diplodus annularis, Diplodus cervinus, Epinephelus marginatus, Epinephelus costae and Epinephelus aenus. Species of Labrids were not affected by protection, except for Thalassoma pavo and Symphodus ocellatus. Meta-analysis of temporal data allows evaluation of the protection MPA provide and is particularly useful when data sources
have different experimental designs or sampling programs. The Tabarca MPA has benefited fish populations by increasing their
abundance and we suggest that meta-analysis is a complementary tool for the management of MPAs.