Do Seabirds Control Wind Drift during Their Migration across the Strait of Gibraltar? A Study Using Remote Tracking by Radar

This study presents data on the directional flying behaviour of the five most abundant seabird species migrating across the Strait of Gibraltar in relation to the wind, as observed from the north coast, based on radar tracking, and identified to species level by visual observations. A total of 318 seabird trajectories were analysed, illustrating the expected east-west or west-east movements in spring and autumn. We hypothesised that the seabirds that cross the Strait channel during their migrations would behave differently with respect to compensation for wind direction, depending on their flight styles, the migratory period, and the prevailing winds. In this regard, our results showed that flapping birds (Razorbill, Puffin, Northern Gannet, and Balearic shearwater) compensated for wind drift independently of the season and the predominant wind direction. This agrees with the theory that suggests that under moderate winds and whenever visual contact with the coastline is present (as in the case of our study), migrants should compensate for wind drift to avoid being drifted towards the coast, off their main direction of flight. However, Cory's shearwater, an active gliding seabird with long, slender wings, showed an adaptive directional response to wind, allowing it to be drifted in spring when westerly tailwinds were prevalent, but compensated for wind in autumn, when both easterly and westerly winds were similarly frequent. This adaptive flight behaviour allows it to take advantage of the prevailing tailwinds in spring, gaining ground speed and saving energy during its passage through the Strait, while in autumn, more frequent headwind conditions and a more directional migration to the south may favour compensating for wind drift. Our results support the usefulness of bird radar as a remote tool for describing the pattern of animal movements in the marine environment, as well as their behavioural response to atmospheric conditions. These studies are particularly relevant in the current framework of climate change

Correlation between seabirds and fisheries varies by species at fine-scale pattern

Understanding how fisheries influence seabird distribution is critical in the development of sustainable fisheries management. Species distribution models were applied to analyse the influence of the fishing footprint, discards, and oceanographic factors on seabird attendance patterns to trawlers in the Gulf of Cadiz. More than 30 species of seabirds were attracted to trawlers, although only seven were registered with relatively high frequency and abundance. For these species, fishery footprint was a good predictor for the distribution of four out of seven (yellow-legged gull, lesser black-backed gull, northern gannet, and Cory's shearwater). Yellow-legged and lesser black-backed gull flocked in large numbers to trawlers, mostly in shallow areas where they were also attracted by purse seines. Northern gannets and Cory's shearwaters appeared with relatively high frequency and their distributions correlated with trawler effort and abundance of potential prey discards. Balearic shearwaters were attracted in low numbers and concentrated in shallow areas, where potential prey discards were also more abundant. For these three species, discards as surrogate of natural prey distribution were good predictors of trawler attendance. Our research revealed that, at a local scale, the degree of interaction of seabirds on fishing discards varies by species. Therefore, fine-scale studies are essential in identifying interactions between seabirds and fisheries, and thus assessing conservation issues such as bycatch or the consequences of discard bans.This research has been carried out within the framework of the ECOFISH project: Eco-innovative strategies for sustainable fishing in the Gulf of Cadiz SPA. This initiative has been supported by the Biodiversity Foundation, the Ministry for Ecological Transition and Demographic Challenge, through the Pleamar Program, co-financed by the European Maritime and Fisheries Fund (EMFF) [grant number: 2019016/PV/PLEAMAR18/PT; 2020-013/PV/PLEAMAR19/PT; 2020-055/PV/PLEAMAR20/PT; 2021/PV/PLEAMAR2021/PT]

Performance and emissions of a diesel engine using sunflower biodiesel with a renewable antioxidant additive from bio-oil

The aim of this study is to test the behaviour of sunflower biodiesel in a diesel engine after being treated with a natural antioxidant additive produced from bio-oil extraction (final dosage of bio-oil compounds in doped biodiesel of 1.9 wt%). The influence of this renewable additive in both the engine performance and the produced emissions was evaluated. Five more fuels were used for the sake of comparison: petroleum diesel, neat sunflower biodiesel without additives, commercial biodiesel, commercial B10 blend and another B10 blend prepared from petro-diesel and doped sunflower biodiesel. Brake power was found to be similar for the six fuels, while the brake specific fuel consumption and the brake thermal efficiency were higher for biodiesel fuels. Only slight differences (<1%) were observed between the doped biodiesel and the neat one, showing that the bio-oil based additive did not negatively affect the general performance of the engine. Regarding gas emissions (analysed according to the European Stationary Cycle), weighted average emissions of NOx and CO2 were higher for biodiesel fuels, while CO and opacity factor were lower in that case. Incorporating the bio-oil based additive reduced NOx emissions and smoke opacity by 3.0% and 4.4% compared with neat biodiesel, respectively, whilst CO and HC emissions increased by 0.7 and 14.3% respectively, values still remaining below those of diesel

Performance and emissions of a diesel engine fueled with biodiesel doped with a renewable antioxidant additive

1. INTRODUCTION Biodiesel is a mixture of alkyl esters obtained by transesterification of vegetable oils and animal fats with a short chain alcohol (mainly methanol or ethanol) and catalyzed by acids or bases (usually NaOH or KOH) [1]. Final properties of the biodiesel are similar to those of petroleum derived-diesel. Therefore, biodiesel can be used in diesel conventional engines without significant modifications or mixed in any proportion with fossil diesel. Some of the main drawbacks of biodiesel to be used as fuel are the low oxidation stability and poor cold flow properties (freezing point and flowability of the fuel at low temperatures), both highly dependent on the raw material composition. Saturated compounds are responsible for the poor cold flow properties of biodiesel, whereas unsaturated esters are mainly responsible for its oxidation [2]. Different synthetic and costly additives [3-6] have been used by manufacturers to improve biodiesel characteristics in order to fulfill the requirements defined in different standards, such as EN 14214 in Europe. Please click Additional Files below to see the full abstract

Drivers for spatial modelling of a critically endangered seabird on a dynamic ocean area: Balearic shearwaters are non-vegetarian

1. Spatial modelling is an important research tool to improve our knowledge about the distribution of wildlife in the ocean. Using different modelling techniques (MaxEnt and a generalized linear mixed model), a predictive habitat suitability model was developed for one of the most threatened seabirds in the world: the Balearic shearwater, Puffinus mauretanicus. 2. Models were developed using a 10-year dataset from the Gulf of Cádiz (on the south-western Iberian Peninsula), a key foraging area for Balearic shearwaters during migration and the non-breeding season. 3. Predictive habitat maps strongly matched the observed distribution patterns, pointing to bathymetric features as the main modelling drivers. The species was concentrated on shallow areas (up to approximately 100 m in depth) of the continental shelf, very close to the mouth of the Guadalquivir River. In contrast with previous studies, Balearic shearwater distribution in the highly dynamic Gulf of Cádiz was not correlated with areas of high chlorophyll a concentration. 4. This lack of spatial correlation probably arises from the delay between the phytoplankton bloom and the response of the zooplankton and small fish that are preyed upon by Balearic shearwaters, which may result in important displacements of this trophic chain across the Gulf of Cádiz. 5. The analysis presented contributes to a better understanding of the spatial distribution and ecology of the critically endangered top predator in the Gulf of Cádiz and offers important information to improve management plans.Versión del editor1,92

Artisanal trawl fisheries as a sentinel of marine litter pollution

Systematic seafloor surveys are a highly desirable method of marine litter monitoring, but the high costs involved in seafloor sampling are not a trivial handicap. In the present work, we explore the opportunity provided by the artisanal trawling fisheries to obtain systematic data on marine litter in the Gulf of Cadiz between 2019 and 2021. We find that plastic was the most frequent material, with a prevalence of single-use and fishing-related items. Litter densities decreased with increasing distance to shore with a seasonal migration of the main litter hotspots. During pre-lockdown and post-lockdown stages derived from COVID-19, marine litter density decreased by 65 %, likely related to the decline in tourism and outdoor recreational activities. A continuous collaboration of 33 % of the local fleet would imply a removal of hundreds of thousands of items each year. The artisanal trawl fishing sector can play a unique role of monitoring marine litter on the seabe

Guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

Primera guía visual de las especies de animales (25 especies) y macroalgas (25 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados .Fundación Biodiversidad del Ministerio para la Transición ecológica, CEIMA

Nueva guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados.

Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados. Se incluyen mas del doble de las especies que aparecían en la guía publicada en 2019. Dos de las especies de animales añadidas fueron recientemente descritas como nuevas para la Ciencia a partir de material encontrado en La Caleta (en parte).Universidad de Cádiz Ministerio de Ciencia e Innovación Fundación Española de Ciencia y Tecnología (FECYT) Campus de Excelencia Internacional del MAR (CEIMAR)108 pagina