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Marine protected areas are considered a useful tool to preserve and recover the biodiversity of ecosystems. It is suggested that fisheries not only affect populations of target and bycatch species but also their parasite communities. Parasites can indicate fishery effects on host species and also on the whole local community, but the effects of fisheries and protection measures on parasite communities are relatively unknown. This study analyses parasite communities of the white seabream Diplodus sargus sargus in order to assess potential effects exerted by protection measures within and by fisheries outside a reserve in the western Mediterranean Sea. This small scale analysis offered the opportunity to study different degrees of fishery effects on parasite infracommunities, without considering climatic effects as an additional factor. Parasite infracommunities of fishes from the no-take zone (NTZ) differed in their composition and structure compared with areas completely or partially open to fisheries. The detected spatial differences in the infracommunities derived from generalist parasites and varied slightly between transmission strategies. Monoxenous parasites were richer and more diverse in both fished areas, but more abundant in the notake, whereas richness and abundance of heteroxenous parasites were higher for the NTZ. In addition to host body size as one factor explaining these spatial variations, differences within parasite infracommunities between the areas may also be linked to increased host densities and habitat quality since the implementation of the NTZ and its protection measures.

A characterization of the thermal ecology of fishes is needed to better understand changes in ecosystems and species distributions arising from global warming. The movement of wild animals during changing environmental conditions provides essential information to help predict the future thermal response of large marine predators. We used acoustic telemetry to monitor the vertical movement activity of the common dentex (Dentex dentex), a Mediterranean coastal predator, in relation to the oscillations of the seasonal thermocline during two summer periods in the Medes Islands marine reserve (NW Mediterranean Sea). During the summer stratification period, the common dentex presented a clear preference for the warm suprathermoclinal layer, and adjusted their vertical movements following the depth changes of the thermocline. The same preference was also observed during the night, when fish were less active. Due to this behaviour, we hypothesize that inter-annual thermal oscillations and the predicted lengthening of summer conditions will have a significant positive impact on the metabolic efficiency, activity levels, and population dynamics of this species, particularly in its northern limit of distribution. These changes in the dynamics of an ecosystem’s keystone predator might cascade down to lower trophic levels, potentially re-defining the coastal fish communities of the future

Detailed examination of the absorption spectra from dark ocean samples allowed us to identify and deconvolve two distinct chromophores centered to 302 nm (UV) and 415 nm (visible) from the exponential decay curve characteristics of humic substances. The UV chromophore was ubiquitous in intermediate and deep waters, and it has been proposed as the secondary absorption peak of nitrate. The visible chromophore was prominent at the central and intermediate water masses of the North Pacific, and it has been proposed as cytochrome c. Subtraction of the modeled absorption spectra of the two chromophores from the measured absorption spectrum of the samples leads to a spectral slope overestimation by 13.3+-6.0% for S 275-295 and 14.8+-10.6% for S 350-400. To only consider the chromophoric fraction of DOM, the absorption spectra of nitrate should be substracted in samples with a [NO3-]:a 302 ration > 70 micromoles

Parasites are useful bioindicators of anthropogenic impacts such as pollution or overfishing, but also to assess the role of marine protected areas (MPAs) and effects of fisheries management on ecosystems. This study evaluates potential differences in metazoan parasite communities of Diplodus sargus (Sparidae) inside and outside the marine reserve of Medes Islands (NW Mediterranean), in order to explore the use of parasites as indicators of the “reserve effect”. In the framework of the project MAPUCHE, 54 specimens of D. sargus were captured outside (fished area), within the partially protected zone (buffer area) and inside the fully protected zone (no-take area) of the marine reserve. Fish specimens were captured with long line, gillnet and fishing rod by artisanal fishermen. Samples were gathered in winter, spring and summer in the fished and buffer areas and in spring in the no-take area (2008–2009). PERMANCOVA and GLM analyses of data among seasons revealed non-significant differences between fished and buffer area and an effect of season on parasite communities. Thus, pooled abundance data for spring of fished and buffer areas was compared with data from the no-take area. Multivariate analyses revealed a good differentiation of the parasite communities between the fished-buffer area and the no-take area. The higher abundance of the monoxenous parasites (Lamellodiscus spp.) agrees with previous studies indicating a higher density of D. sargus in the no-take area. Moreover, the homogeneous distribution of heteroxenous parasites in the no-take area reflects the already described site fidelity of this species.

Cold-water coral (CWC) reefs constitute one of the most complex deep-sea habitats harboring a vast diversity of associated species. Like other tropical or temperate framework builders, these systems are facing an uncertain future due to several threats, such as global warming and ocean acidification. In the case of Mediterranean CWC communities, the effect may be exacerbated due to the greater capacity of these waters to absorb atmospheric CO2 compared to the global ocean. Calcification in these organisms is an energy-demanding process, and it is expected that energy requirements will be greater as seawater pH and the availability of carbonate ions decrease. Therefore, studies assessing the effect of a pH decrease in skeletal growth, and metabolic balance are critical to fully understand the potential responses of these organisms under a changing scenario. In this context, the present work aims to investigate the medium- to long-term effect of a low pH scenario on calcification and the biochemical composition of two CWCs from the Mediterranean, Dendrophyllia cornigera and Desmophyllum dianthus. After 314 d of exposure to acidified conditions, a significant decrease of 70 % was observed in Desmophyllum dianthus skeletal growth rate, while Dendrophyllia cornigera showed no differences between treatments. Instead, only subtle differences between treatments were observed in the organic matter amount, lipid content, skeletal microdensity, or porosity in both species, although due to the high variability of the results, these differences were not statistically significant. Our results also confirmed a heterogeneous effect of low pH on the skeletal growth rate of the organisms depending on their initial weight, suggesting that those specimens with high calcification rates may be the most susceptible to the negative effects of acidification.

Knowledge of the nutritional conditions of coastal commercial fish populations is key to understanding stock health status, and is essential when making reasonable exploitation and management plans. Here, we present the first results on the condition and feeding preferences of two coastal fish species, Diplodus sargus (Linnaeus, 1758) and Pagellus erythrinus (Linnaeus, 1758). Using stable isotope and biochemical analyses, we tested the potential effects of a marine protected area (MPA) and the occurrence of a dramatic coastal storm on the condition and quality of nutrition. The results suggest that both condition (lipids) and nutrition quality (fatty acids, FAs) in P. erythrinus and D. sargus depend upon on food availability in the area in which they were captured. Pagellus erythrinus individuals inside the MPA stored higher quantities of lipids [46.73 19.00 lg lipid mg organic matter (OM) 1] than those outside the MPA (15.63 5.30 lg lipid mg OM 1) only before the storm. Diplodus sargus showed different FA signatures inside and outside the MPA before and after the storm. These results suggest that D. sargus increased their quality of nutrition inside (16.62 3.17 lg FA mg OM 1) versus outside (7.88 2.36 lg FA mg OM 1) the MPA, owing to increased food diversity and availability. Conversely, P. erythrinus did not show differences in nutritional quality inside (18.12 1.13 lg FA mg OM 1) or outside (18.81 1.42 lg FA mg OM 1) the MPA, possibly because of the increase in ingestion not affecting the studied parameters. In P. erythrinus, the FA concentration decreased after the storm, but in D. sargus, a change in lipid composition was observed. These results suggest that P. erythrinus appears to be more impacted by food quality (different saturated and unsaturated FAs) than D. sargus, owing to a more restrictive diet. We hypothesize that the observed differences between inside and outside the MPA are not only related to the degree of protection, but also to the feeding pref

Deep-water ecosystems are characterized by relatively low carbonate concentration values and, due to ocean acidification (OA), these habitats might be among the first to be exposed to undersaturated conditions in the forthcoming years. However, until now, very few studies have been conducted to test how cold-water coral (CWC) species react to such changes in the seawater chemistry. The present work aims to investigate the mid-term effect of decreased pH on calcification of the two branching CWC species most widely distributed in the Mediterranean, Lophelia pertusa and Madrepora oculata. No significant effects were observed in the skeletal growth rate, microdensity and porosity of both species after 6 months of exposure. However, while the calcification rate of M. oculata was similar for all colony fragments, a heterogeneous skeletal growth pattern was observed in L. pertusa, the younger nubbins showing higher growth rates than the older ones. A higher energy demand is expected in these young, fast-growing fragments and, therefore, a reduction in calcification might be noticed earlier during long-term exposure to acidified conditions.

Parasites are used as biological tags in marine organisms, e.g. invertebrates, fishes and mammals. Some of these studies focus on migration events and/or stock separation of fishes, but they are also used as bio-markers for pollution events. In frame of the project “Una aproximación interdisciplinar al manejo y conservación marina: experiencias divergentes como base de estrategias globales” (Marine Protected Units in Chile and España, MAPUCHE), supported by the BBVA foundation, we studied the parasitic fauna of two fish species in the Marine Reserve of Medes Islands and its surroundings. The main goal of the study was to evaluate possible differences in the parasitic fauna of two fish species (taxonomic groups and abundance) inside and outside the reserve of Medes, in order to use parasites as a tag of the “reserve effect”. Both fish species were captured in the buffer zone (partially protected) and outside of the marine reserve of Medes Islands (NW Mediterranean). The selected species were the common pandora (Pagellus erythrinus) and the white seabream (Diplodus sargus). Fish specimens were all captured by long line or gillnet by artisanal fishermen from L’Estartit. The whole metazoan parasite fauna (ecto- and endoparasites) have been studied for 46 specimens of the common pandora and 42 of the white seabream throughout the four year seasons during 2008 and 2009. The buffer zone of Medes exhibit a minor anthropogenic impact (artisanal fisheries, recreational diving), whereas the unprotected areas in the surrounding waters are subjected to a higher degree of anthropogenic impacts (bottom trawling, recreational fisheries, spearfishing, among others). The results showed slight differences considering the presence and abundance of single parasite groups between fishes of the two studied zones. However, a general tendency of a distinct parasitic fauna in both zones (protected and unprotected) has not been observed. Statistical significant differences were detectable onl