Palma, Spain
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Ingram G.W.,National Oceanic and Atmospheric Administration | Alvarez-Berastegui D.,ICTS SOCIB | Reglero P.,Spanish Institute of Oceanography | Balbin R.,Spanish Institute of Oceanography | And 2 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2017

Fishery independent indices of bluefin tuna larvae in the Western Mediterranean Sea are presented utilizing ichthyoplankton survey data collected from 2001 through 2005 and 2012 through 2013. Indices were developed using larval catch rates collected using two different types of bongo sampling, by first standardizing catch rates by gear/fishing-style and then employing a delta-lognormal modeling approach. The delta-lognormal models were developed three ways: 1) a basic larval index including the following covariates: time of day, a systematic geographic area variable, month and year; 2) a standard environmental larval index including the following covariates: mean water temperature over the mixed layer depth, mean salinity over the mixed layer depth, geostrophic velocity, time of day, a systematic geographic area variable, month and year; and 3) a habitat-adjusted larval index including the following covariates: a potential habitat variable, time of day, a systematic geographic area variable, month and year. Results indicated that all three model-types had similar precision in index values. However, the habitat-adjusted larval index demonstrated a high correlation with estimates of spawning stock biomass from the previous stock assessment model, and, therefore, is recommended as a tuning index in future stock assessment models. © 2017.

Palmer M.,CSIC - Mediterranean Institute for Advanced Studies | Pons G.X.,University of the Balearic Islands | Outerelo R.,Complutense University of Madrid | Vives E.,San Antoni 73 | And 5 more authors.
Bolleti de la Societat d'Historia Natural de les Balears | Year: 2012

Inventory-based approaches (i.e., those that directly relate species richness to explanatory variables) do not work on the medium and local scale that was studied in this paper; even when ecologically-meaningful environmental predictors were used. The use of an alternative approach (Taxon-based diversity mapping) is proposed. This approach starts by modelling the probability of occurrence of twelve target endemic species using environmental variables as predictors. Next, it projects the probability of occurrence from 48 sampled sites to a grid of 532 1-km2 units. Finally, the approach estimates endemic species richness at these 532 1-km2 units by overlapping the twelve maps inferred. We also propose a new approach whose purpose is to detect possible false absences and unstable presences. These doubtful observations were excluded from ecological niche modelling. In addition to species richness, the patterns experienced by species composition were analysed. Species composition experienced strong changes (i.e., large turnover), while species richness remained constant. This stasis in species richness is neither related to low environmental variability (both the biotic and abiotic scenarios are diverse) nor to the lack of species-environment relationships (not only species composition but also species-specific responses are correlated with environment). The area studied is environmentally diverse and species turnover of the macroinvertebrate community was moderate to large. Species composition was significantly correlated with environment (minimum temperature). The predicted number of target endemic species per cell in 92% of the studied area fell between 3 and 5. Therefore Taxonbased diversity mapping has been confirmed as a valid alternative to conventional inventory-based diversity mapping. Additionally, the new procedure proposed here for dealing with noisy presence/absence data produces more accurate distributional maps of individual species.

Renault L.,ICTS SOCIB | Chiggiato J.,Undersea Research Center | Chiggiato J.,National Research Council Italy | Warner J.C.,U.S. Geological Survey | And 4 more authors.
Journal of Geophysical Research: Oceans | Year: 2012

The coastal areas of the North-Western Mediterranean Sea are one of the most challenging places for ocean forecasting. This region is exposed to severe storms events that are of short duration. During these events, significant air-sea interactions, strong winds and large sea-state can have catastrophic consequences in the coastal areas. To investigate these air-sea interactions and the oceanic response to such events, we implemented the Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System simulating a severe storm in the Mediterranean Sea that occurred in May 2010. During this event, wind speed reached up to 25 m.s-1 inducing significant sea surface cooling (up to 2°C) over the Gulf of Lion (GoL) and along the storm track, and generating surface waves with a significant height of 6 m. It is shown that the event, associated with a cyclogenesis between the Balearic Islands and the GoL, is relatively well reproduced by the coupled system. A surface heat budget analysis showed that ocean vertical mixing was a major contributor to the cooling tendency along the storm track and in the GoL where turbulent heat fluxes also played an important role. Sensitivity experiments on the ocean-atmosphere coupling suggested that the coupled system is sensitive to the momentum flux parameterization as well as air-sea and air-wave coupling. Comparisons with available atmospheric and oceanic observations showed that the use of the fully coupled system provides the most skillful simulation, illustrating the benefit of using a fully coupled ocean-atmosphere-wave model for the assessment of these storm events.

Sayol J.M.,CSIC - Mediterranean Institute for Advanced Studies | Orfila A.,CSIC - Mediterranean Institute for Advanced Studies | Simarro G.,CSIC - Institute of Marine Sciences | Conti D.,CSIC - Mediterranean Institute for Advanced Studies | And 2 more authors.
Environmental Modelling and Software | Year: 2014

An operational model for tracking surface objects in the ocean is presented. Contrary to most of traditional Lagrangian Particle Tracking Algorithms, the presented approach computes the probability density function from the final position of a set of neutrally buoyant particles deployed in the flow providing the area of accumulated probability. The model departs from daily predictions of ocean surface currents, winds and waves provided by an Operational Forecasting System, and integrates the Eulerian velocities to obtain the trajectory of each particle forward in time. A random walk term is added to simulate numerical diffusivity. Several tests are performed in order to determine the optimal numerical scheme as well as the computational time step. To show the performance of the model we simulate the trajectories of a set of SVP-drifters deployed in the Balearic Sea. For these experiments, the final position of the drifters laid within the modeled contour of 50% of accumulated probability for the first 24h forecast. © 2013 Elsevier Ltd.

Ponce de Leon S.,CSIC - Mediterranean Institute for Advanced Studies | Orfila A.,CSIC - Mediterranean Institute for Advanced Studies | Gomez-Pujol L.,ICTS SOCIB | Renault L.,ICTS SOCIB | And 2 more authors.
Applied Ocean Research | Year: 2012

A wave hindcast in the Western Mediterranean Sea is carried out in order to assess the performance of three atmospheric models in providing the forcing for a third generation wave model. The wind models have been used as forcing fields for the generation of waves and the resulting significant wave height time history compared with four buoys around the Balearic Islands. Two different wave-model grid resolutions are used to get the wave field in the entire Mediterranean and around the Balearic Islands. The present application was performed for three months: November 2008 and for July and August 2009. Results indicate that all data sources provide good forcing for operational wave forecast at large scales (wind forecast with grid resolution of 30 and 25. km). Near the coast or at the lee of islands, resolving small scale topographical features result in a better forecast of wave fields. However, for the area studied, the atmospheric model that better represents summer and winter conditions is hourly WRF at 1.5. km resolution. © 2011 Elsevier Ltd.

Terrados J.,CSIC - Mediterranean Institute for Advanced Studies | Diedrich A.,ICTS SOCIB | Arroyo N.L.,CSIC - Mediterranean Institute for Advanced Studies | Balaguer P.,ICTS SOCIB
Bolleti de la Societat d'Historia Natural de les Balears | Year: 2012

Recreational boating is an important economic activity in the Mediterranean Sea that often leads to disturbance by anchoring of Posidonia oceanica meadows, an endemic seagrass that is a critical component of shallow coastal ecosystems. A selfadministered survey of recreational boaters that anchor in a popular mooring site (Cala Blava) in the coast of Mallorca (Balearic Islands, Western Mediterranean) was carried out during the summer season of 2011 to assess their preferences regarding the number of boats anchoring at the cove and the distance between them, their willingness to pay for the use of mooring buoys and their perception of the negative effects that recreational boating may have on the marine environment. Four hundred and twenty five surveys were obtained over a period of 23 days (11 weekend days, 14 week days) with a response rate of 95 %. The number of boats anchored was higher during weekends (30 ± 13 boats) than during the rest of the week (15 ± 5 boats). Most of the respondents considered that both the number of anchored boats and distance between them were adequate, and they were satisfied with their visit to Cala Blava. Anchor damage was identified as the main impact caused in the marine environment by recreational boating. Support for the use of mooring buoys was high (72 %) and 58 % of boaters were willing to pay a fee for buoy use. The most widely accepted fee was 5 Euros per day of use. These results suggest that the public is well aware of the damage caused by anchoring on P. oceanica meadows and that environmental regulation that would reduce this harm through the use of mooring buoys would have wide support from the main users, who would be even willing to pay for the service. This is a bright prospect for the conservation of this valuable and fragile coastal ecosystem.

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