Decadal variability 2010-2021 of zooplankton community at the Guadalquivir estuary (southern Spain)

A Long Term Ecological Research Program has been monitoring the Guadalquivir estuary meso- and macro- zooplankton community monthly since January 2010. As an important nursery area for many marine species (fish and crustacean) from the Gulf of Cadiz, whose juveniles and recruits depend on zooplankton as main prey, understanding how abiotic and biotic factors determine zooplankton community structure it´s necessary to unreveal recruitment variability. We sampled throughout the whole salinity gradient, 2 locations, the two diurnal ebb and flood tides during the new moon days using a 100 μm zooplankton net. Zooplankton community is mainly composed by copepods and mysids. While the exotic Acartia tonsa calanoid copepod is the most abundant specie by abundance, mysid Mesopodopsis slabberi contribute the most to total biomass, followed by mysids Rhopalophthalmus tartessicus and Neomysis integer. Other abundant groups were copepods Acartia bifilosa and Acartia clausii, Calanipeda aquaedulcis, Paracalanus parvus and Acanthocyclops robustus, cladocera Pleopis polyphaemoides, together with veliger larvae, Cirripeda and Ostracoda, and Decapoda larvae. About total biodiversity, we found up to 183 species, estimating a total mean Species Richness of 9.7 (minimum 2- maximum 33) per sample, mean Shannon Diversity Index 3.27, Pielou Evenness 0.50 and mean betadiversity 0.630. While copepods area abundant form fall to early spring and summer, mysid density peaks form spring to fall. Community is structured by Salinity, but Temperature, Turbidity, Nitrate, Nitrite and Dissolved Oxygen were also important variables leading spatio-temporal variability, mainly when estuary recives high freshwater discharges from Alcala del Río dam

Population dynamic and trophic position of mysid community demonstrates its key role for nursery function in a temperate estuary

Guadalquivir Estuary is a main nursery ground of marine goal species for Gulf of Cadiz fisheries. It is a well-mixed temperate estuary with horizontal salinity gradient and clear seasonal water temperature trend. Mysid community with Mesopodopsis slabberi, Neomysis integer and Rhopalophthalmus tartessicus make up to over 80% of total macrofauna biomass in the estuary. Life history, population structure, secondary production, trophic level and community spatio-temporal dynamic were unravelled combining analysis of long term 16y monitoring data with 2y of in depth population analysis and trophic biomarker studies. Results show a key trophic role in food web, a seasonal trend showing density peaks ( 23, 3 and 6 mg/m3, respectively) in spring-summer and winter marine coastward migration. Despite being euryhaline, the three species of showed unevenly spatial distribution, being salinity the variable best explaining structure changes of mysid assemblage. Inter- and intra-specific euryhalinity differences both for prey and predators seem to determine the entire spatial estuarine community distribution. High secondary production (P/B rates 38.2, 10.3 and 10.7) and food web studies confirm key role of mysids transferring energy up to juveniles (fish and crustaceans) arriving yearly in spring to their nursery area

Variación estacional de la condición nutricional larvaria del boquerón (Engraulis encrasicolus) en el estuario del Guadalquivir

European anchovy recruitment to the Guadalquivir estuary mainly occurs when the environmental conditions show more stability. Unusual changes in the environmental conditions of this estuary negatively impacted on key preys of anchovy and therefore on its nursery function. In this way, nutritional condition should determine strongly the physiological state of this species in estuaries and thus its survival and recruitment. RNA:DNA ratio has been applied with success as indicator of nutritional condition and growth in marine organisms. We study RNA:DNA ratio in anchovies of the coupled system Guadalquivir estuary-coastal influenced area in the Gulf of Cádiz in order to evaluate the condition seasonal variability of this species along this spatial gradient. Spatial differences in the size distribution of anchovy and high values of RNA:DNA in the Guadalquivir estuary compared to its influence coastal area suggest that anchovies migrate to the estuary and they acquire a very good condition. We conclude that RNA:DNA is an useful tool to understand the ecological mechanisms by which the coupled system Guadalquivir estuary-coastal influenced area in the Gulf of Cádiz control the success or failure of the recruitment of this important fishery resource in the region

Variación estacional de la condición nutricional larvaria del boquerón (Engraulis encrasicolus) en el estuario del Guadalquivir

Trabajo presentado en el VIII Simposio sobre el Margen Ibérico Atlántico (MIA15), celebrado en Málaga del 21 al 23 de septiembre de 2015.Peer reviewe

Decadal variability 2010-2021 of zooplankton community at the Guadalquivir estuary (Southern Spain)

Resumen del trabajo presentado en Symposium on Decadal Variability of the North Atlantic and its Marine Ecosystems: 2010-2019, celebrado en Bergen (Noruega) del 20 al 22 de junio de 2022.A Long Term Ecological Research Program has been monitoring the Guadalquivir estuary meso- and macro- zooplankton community monthly since January 2010. As an important nursery area for many marine species (fish and crustacean) from the Gulf of Cadiz, whose juveniles and recruits depend on zooplankton as main prey, understanding how abiotic and biotic factors determine zooplankton community structure it´s necessary to unreveal recruitment variability. We sampled throughout the whole salinity gradient, 2 locations, the two diurnal ebb and flood tides during the new moon days using a 100 μm zooplankton net. Zooplankton community is mainly composed by copepods and mysids. While the exotic Acartia tonsa calanoid copepod is the most abundant specie by abundance, mysid Mesopodopsis slabberi contribute the most to total biomass, followed by mysids Rhopalophthalmus tartessicus and Neomysis integer. Other abundant groups were copepods Acartia bifilosa and Acartia clausii, Calanipeda aquaedulcis, Paracalanus parvus and Acanthocyclops robustus, cladocera Pleopis polyphaemoides, together with veliger larvae, Cirripeda and Ostracoda, and Decapoda larvae. About total biodiversity, we found up to 183 species, estimating a total mean Species Richness of 9.7 (minimum 2- maximum 33) per sample, mean Shannon Diversity Index 3.27, Pielou Evenness 0.50 and mean betadiversity 0.630. While copepods area abundant form fall to early spring and summer, mysid density peaks form spring to fall. Community is structured by Salinity, but Temperature, Turbidity, Nitrate, Nitrite and Dissolved Oxygen were also important variables leading spatio-temporal variability, mainly when estuary recives high freshwater discharges from Alcala del Río dam

Spatial distribution and estuarine sources of dissolved organic matter export to the coastal zone in the Gulf of Cádiz, Spain

Trabajo presentado en el XVIII Seminario Ibérico de Química Marina, celebrado en Alicante (España) de 20 al 22 de julio de 2016.Dissolved organic matter (DOM) is a major component of the organic matter transported to the coastal zone by rivers. It controls ecosystem-level processes (e.g. food web) and constitutes an important pathway for nutrients transport from land to coastal waters. We know that estuarine discharges affect the primary production and nutrient composition in the adjacent coastal area. For instance, the current hypernutrification of the Guadalquivir estuary may benefit primary production on adjacent coasts. However, studies on DOM in the Gulf of Cádiz waters are unknown despite its importance in the global ocean functioning. The Gulf of Cádiz is under the estuarine influence of three main estuaries: Guadiana, Tinto-Odiel and Guadalquivir. The present study evaluates the relevance of DOM and the estuarine influence and environmental factors which determine its distribution in the Gulf of Cádiz. Our results suggest that the Gulf of Cádiz water mass is receiving large amounts of dissolved organic transported by the Guadiana and Guadalquivir rivers and much lesser from Tinto-Odiel. Thus, the estuarine influenced area explained the fDOM variability in the Gulf of Cadiz and this variability was shaped by turbidity, water depth and distance from the coast. Within the estuarine ecosystems, salinity and turbidity were the main factors explaining the fDOM variability.This work was financed by the MICCIN grants DILEMA (CTM2014-59244-C3-2-R).N

SOLE FARMING: There or thereabouts!

After years of uncertainty, it is a pleasure to report that sole is now being commercially farmed in significant quantities in Europe! Even though production levels are modest compared with other well-established species and there is still a considerable amount to be done to underpin the further development of the industry, a significant increase in production did provide positive cause for optimism at the latest Workshop on the Cultivation of Soles. The fifth Workshop in a series which began in 2002 was held from 5-7 April 2011 and was again hosted by CCMAR, University of the Algarve, Faro, Portugal where we were able to benefit from their excellent facilities and organizational support. An account of the previous Workshop was published in this journal (vol. 34/1). Despite the recent severe financial pressures, the level of interest in this Workshop was high with 75 registered participants. As the countries with the greatest involvement in the field Spain & Portugal contributed a large majority (86%) of these. The rest were from Norway, The Netherlands, Italy, UK and France, another country where significant production facilities are being developed. About a third of the participants were from industry, reflecting the present high level of commercial interest. This included almost all current producers, as well as many actively contemplating entering the field, and those involved in support industries such as feed and pharmaceutical companies. As previously, the Workshop sought to review the current status of the industry and, through discussions informed by presentations of current research, to identify viable options for alleviating current constraints. Thus, about one third of the Workshop was dedicated to formal presentations, the remainder to open discussion. The presentations provided clear evidence of the quality and diversity of research that is being undertaken in support of this embryonic industry. Encouragingly, a large proportion of the presentations were delivered by young post-graduate students or postdocs, providing tangible evidence of a new generation of innovative scientists entering the field!.Peer Reviewe

Age is indicated as days after hatching (lower, Senegalese sole; upper, for Atlantic halibut)

Metamorphosis period is shaded.<p><b>Copyright information:</b></p><p>Taken from "Selection of housekeeping genes for gene expression studies in larvae from flatfish using real-time PCR"</p><p>http://www.biomedcentral.com/1471-2199/9/28</p><p>BMC Molecular Biology 2008;9():28-28.</p><p>Published online 6 Mar 2008</p><p>PMCID:PMC2275743.</p><p></p