Spatial patterns of ß-diversity under cumulative pressures in the Western Mediterranean Sea.

Understanding the spatial dynamics of biodiversity is an essential issue in marine ecology and requires combining information at local and regional scales. ß-diversity is an important measure of biodiversity that informs on the differences in community composition between sites and, thus, in the species turnover in the community structure. In this study, we analysed and predicted the spatial patterns of ß-diversity for fishes, invertebrates and the demersal assemblage along the Iberian Mediterranean coast. We used Bayesian Bootstrap Generalized Dissimilarity Models (BBGDMs) to study the effects of environment and human pressures on the ß-diversity of invertebrate, fishes and the entire demersal assemblage from 1994 to 2015 using different time windows to account for temporal variability. Then, we used these relationships to predict the spatial patterns of ß-diversity in the whole Iberian Mediterranean coast. Our results highlighted that the regional spatial patterns of ß-diversity were best described by bathymetry and a cumulative index of coastal impacts. We identified specific regions with the highest ß-diversity in the study area, which were complementary to hotspots of species richness and presented different degree of overlapping with existent marine protected areas. Overall, our study illustrates that by modelling spatial turnover using ß-diversity we can better understand and predict spatial variation of biodiversity and the effects of particular variables, providing relevant information to end-users and policy makers for designing specific spatial conservation and management strategies.

Searching for a compromise between biological and economic demands to protect vulnerable habitats.

Identifying vulnerable habitats is necessary to designing and prioritizing efficient marine protected areas (MPAs) to sustain the renewal of living marine resources. However, vulnerable habitats rarely become MPAs due to conflicting interests such as fishing. We propose a spatial framework to help researchers and managers determine optimal conservation areas in a multi-species fishery, while also considering the economic relevance these species may have in a given society, even in data poor situations. We first set different ecological criteria (i.e. species resilience, vulnerability and trophic level) to identify optimal areas for conservation and restoration efforts, which was based on a traditional conservationist approach. We then identified the most economically relevant sites, where the bulk of fishery profits come from. We overlapped the ecologically and economically relevant areas using different thresholds. By ranking the level of overlap between the sites, representing different levels of conflicts between traditional conservation and fishing interests, we suggest alternatives that could increase fishers' acceptance of protected areas. The introduction of some flexibility in the way conservation targets are established could contribute to reaching a middle ground where biological concerns are integrated with economic demands from the fishing sector.

Identifying ecological barriers in marine environment: The case study of Dasyatis marianae.

Ecological barriers are important determinants of the evolution and distributions marine organisms, and a challenge for evolutionary ecologists seeking to understand population structure in the sea. Dasyatis marianae is an endemic Brazilian species that indicates certain restrictions on its distribution probably due to marine barriers. In this study, Bayesian hierarchical spatial models, jointly with environmental and occurrence species data, are used to identify, which elements could generate these barriers on Dasyatis marianae distribution. Results show that salinity and temperature are the most important drivers that play an essential role to limit the distribution of this species. Indeed, low salinity values restrict Dasyatis marianae distribution in the north of the Brazilian coast, while in the south are colder temperatures. These results highlight the need to better define the distribution of marine species, especially for the ones affected by ecological barriers that are more sensitive to environmental changes.

Ecology of the Atlantic black skipjack Euthynnus alletteratus (Osteichthyes: Scombridae) in the western Mediterranean Sea inferred by parasitological analysis.

Between 2008 and 2011, the head of 150 Euthynnus alletteratus (Osteichthyes: Scombridae) caught inshore off the southeastern Iberian coast (western Mediterranean Sea) were examined for parasites. Two monogeneans, four didymozoid trematodes and four copepods were found. Parasite abundance showed a positive relationship with the annual sea surface temperature, except for Pseudocycnus appendiculatus, but negative with the sea depth (Capsala manteri, Neonematobothrium cf. kawakawa and Caligus bonito). Prevalences and mean abundances differed significantly among sampling areas, except for C. manteri, Oesophagocystis sp. 2 and Ceratocolax euthynni, and sampling years (Melanocystis cf. kawakawa, N.cf. kawakawa, P. appendiculatus and Unicolax collateralis). Results indicate that the parasite abundances of E. alletteratus in the western Mediterranean Sea depend mainly on regional environmental variables, which can show interannual variations. The presence of pelagic parasites, i.e. didymozoids and P. appendiculatus, could indicate that E. alletteratus migrates between inshore and offshore pelagic domains. The different parasite faunas reported in E. alletteratus populations from the western Atlantic Ocean and the Mediterranean Sea appear to point out the geographical host isolation. These results suggest that E. alletteratus inhabiting the western Mediterranean Sea performs inshore-offshore small-scale migrations, and not transoceanic migrations between the western Atlantic Ocean and Mediterranean Sea.

A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale.

The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species' long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075-21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June-September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought.

Modeling sensitive parrotfish (Labridae: Scarini) habitats along the Brazilian coast.

In coral reef environments, there is an increasing concern over parrotfish (Labridae: Scarini) due to their rising exploitation by commercial small-scale fisheries, which is leading to significant changes in the reefs' community structure. Three species, Scarus trispinosus (Valenciennes, 1840), Sparisoma frondosum (Agassiz, 1831) and Sparisoma axillare (Steindachner, 1878), currently labeled as threatened, have been intensively targeted in Brazil, mostly on the northeastern coast. Despite their economic importance, ecological interest and worrisome conservation status, not much is known about which variables determine their occurrence. In this study, we adopted a hierarchical Bayesian spatial-temporal approach to map the distribution of these three species along the Brazilian coast, using landing data from three different gears (gillnets, spear guns, and handlines) and environmental variables (bathymetry, shore distance, seabed slope, Sea Surface Temperature and Net Primary Productivity). Our results identify sensitive habitats for parrotfish along the Brazilian coast that would be more suitable to the implementation of spatial-temporal closure measures, which along with the social component fishers could benefit the management and conservation of these species.