Abundance of Anchovy eggs by CUFES: Inter-annual fluctuations and spatial patterns.

Data on the abundance of Anchovy eggs in the Gulf of Cadiz as collected by CUFES are explored in the present work in relation to their spatial pattern and inter-annual fluctuations. These data were gathered in 12 summer surveys, both acoustic (ECOCADIZ series) and DEPM (BOCADEVA series) ones, since 2004 to date (no survey in 2012). A total of 1499 CUFES stations were sampled, which distributed from the strait of Gibraltar, in Spain, to Cape San Vicente, in Portugal (in 2010 to Cape Sta. Maria only). The sampling scheme consisted in a grid of 21 parallel transects, normal to the shoreline and inter-spaced 8 nm, with the samples being collected every 3 nm at a c.a. 600 l/min flow with a 335 μm mesh size net and at a sampling depth of 5 m from the surface. A continuous record of SST and SSS at 5 m (termosalinometer) was coupled to the CUFES sampling. The surveys were carried out in June, July or August depending on the year. Oceanographic variables such as temperature, salinity and chlorophyll, and even the bottom topography of the shelf as well, they all showed significantly different in two regions: to the East and West of the Cape S. Mª. The density of Anchovy eggs presents a high variability between stations showing a very patched distribution. The stations with most eggs are located to the East of Cape Sta. Mª. Egg abundance also showed a very high between-year variability, ranging from 2955 eggs in 2005 to 41941 eggs collected in 2014. Regarding the spatial pattern of egg distribution, the 84.9% of the total egg density (all the surveys pooled) was collected in the area east of the Cape Sta. Mª (37.4 % in 2016), and the 89.8 % of total egg density in stations bellow 100 m depth (47.9 % in 2016). What happened in 2016? The mean temperature registered in 2016 in the Western stratum (22.0ºC) was practically the same that the mean temperature registered from 2004 to 2015 in the Eastern stratum (21.7ºC). The analysis of the centers of gravity of the eggs densities vs longitude and depth show significant trends, but not for latitude, which indicate a displacement towards the West in 2016. However, no trends were found in the centers of gravity of the acoustic energy (NASC) as a proxy of adults. Is then the westward displacement of the spawning in 2016 caused by an advective transport (currents and/or winds) or by other causes? What will be the further effect on recruitment? It would be good to obtain a statistical model in order to explain how the different variables affect the abundance of eggs, including other variables like the wind, tide... The presence of deep canyons crossing the shelf in the East of Cape Sta. Mª indicates that distance to the coast would be a better variable than depth

BOCADEVA 0714 Gulf of Cadiz Anchovy Egg Survey and 2014 SSB preliminary estimates

This working document provides a brief description of the survey, laboratory analysis and estimation procedures used to obtain the Gulf of Cadiz anchovy SSB by DEPM for 2014 in the South-Atlantic Iberian Stock. Results are preliminary, because the estimation of the spawning fraction is not available yet

Discovering the Fine-Scale Morphology of the Gulf of Cádiz: An Underwater Imaging Analysis

The dense and deep water flow that leaves the Mediterranean Sea to the Atlantic flows through the upper and middle slope of the Gulf of Cádiz as a powerful bottom stream that model sand interacts with bathymetry. The detailed analysis of underwater images,obtained with a photogrammetric sled in the central area of the upper and middle slope of the Gulf of Cádiz, together with multibeam bathymetry and oceanographic and sediment types data, has allowed conducting a detailed study of the seafloor microtopography and the predominant oceanographic dynamics in the study area. Different fine-scale spatial bedforms were identified, such as ripples, dunes, burrows, mounds, obstacle marks, rock bottoms, and low-roughness bottoms using underwater images. Besides, a geostatistical study of the different video transects studied was carried out and allowed us to differentiate three types of bottoms depending on the processes that affect their microtopography.En prens

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

Anchovy Spawning Stock Biomass of the Gulf of Cadiz in 2020 by the DEPM

The Daily Egg Production Method (DEPM) to estimate the Anchovy Spawning Stock Biomass (SSB) in the Gulf of Cádiz (ICES, Subdivision 9a South) is conducted by Spain (Centro Nacional Instituto Español de Oceanografía, CSIC) every three years, since 2005. BOCADEVA 0720 is the sixth survey of the historical DEPM series for anchovy in the Gulf of Cádiz and was delivered on board R/V Ramón Margalef (CNIEO) from the 9th to the 17th of July 2020. The surveyed area extended from Strait of Gibraltar to Cape San Vicente (Spanish and Portuguese waters in the Gulf of Cadiz). Plankton samples, along a grid of 21 transects perpendicular to the coast were obtained for the spawning area delimitation and density estimation of the daily egg production. The survey objectives also included the characterization of the oceanographic and meteorological conditions in the study area. The samples to estimate adult parameters (sex ratio, female mean weight, batch fecundity and spawning fraction) were obtained in the acoustic survey “ECOCADIZ 2020-07”, carried out during the same period. This working document provides a d escription of the survey, laboratory analysis and estimation procedures used to obtain the Gulf of Cadiz Anchovy SSB by DEPM for 2020 in the South-Atlantic Iberian Stock

BOCADEVA 0720. Anchovy DEPM survey in the Gulf of Cadiz

The Daily Egg Production Method (DEPM) to estimate the Anchovy Spawning Stock Biomass (SSB) in the Gulf of Cádiz (ICES, Subdivision 9.a South) is conducted by Spain (Instituto Español de Oceanografía, IEO) every three years, since 2005. BOCADEVA 0720 is the sixth survey of the historical DEPM series for anchovy in the Gulf of Cádiz and was delivered on board R/V Ramón Margalef (IEO) from the 9th to the 17th of July 2020.This working document provides a brief description of the survey and the progress status of t h e laboratory analysis c a r ri e d o u t to obtain the Anchovy SSB by the a ppl i c at i o n o f th e DEPM in the South-Atlantic Iberian Stock

Review of sciaenid culture around the world, with a special focus on the meagre Argyrosomus regius (Asso, 1801)

Interest in culture of sciaenid fishes has grown rapidly in recent years. The present paper reviews the literature on several species belonging to Sciaenidae, cultured around the world: red drum Sciaenops ocellatus (L., 1766), Japanese meagre or mulloway Argyrosomus japonicus (Temminck y Schlegel, 1843), shi drum Umbrina cirrosa (L., 1758), and meagre Argyrosomus regius (Asso, 1801). The meagre is a commercially important fish species whose distribution extends along the Eastern Atlantic coast and the Mediterranean Sea. Experiments carried out in sea cages and indoor tanks have shown similar results in growth rate, but the food conversion rate was higher in cages (2,73) than in tanks (13,88).El interés por el cultivo de peces esciénidos se ha visto incrementado en los últimos años. Se realiza aquí una revisión bibliográfica de cultivos de varias especies de la familia Sciaenidae en el mundo: corvinón ocelado Sciaenops ocellatus (L., 1766), corvina japonesa Argyrosomus japonicus (Temminck y Schlegel, 1843), verrugato Umbrina cirrosa (L., 1758) y corvina Argyrosomus regius (Asso, 1801). La corvina ha adquirido una importancia comercial notable, y se distribuye a lo largo de las costas del Atlántico y el Mediterráneo. Experiencias de cultivo en jaulas y tanques demostraron similares índices de crecimiento, obteniéndose, sin embargo, un mejor factor de conversión del alimento en jaulas (2,73) que en tanques (13,88).Instituto Español de Oceanografí

The evolution of the zooplankton community in the gulf of Cadiz, SW Iberian Peninsula

The Spanish Institute of Oceanography (IEO) has been conducting a multidisciplinary study of the marine ecosystem in the Gulf of Cadiz (GoC; SW Iberian Peninsula) since 2009 within the frame of the program Time Series of Oceanographic data in the Gulf of Cadiz (STOCA, in Spanish). The program maintains repeated observations along five across-shelf transects: three times a year from 2009 to 2012 and quarterly on hereafter. In this paper we present the temporal evolution of the zooplankton community in the GoC. In particular, we focused on samples from three stations located off the Guadalquivir river mouth: GD1 (20 m depth), GD3 (80 m) and GD6 (450 m). Samples were taken with bongo-40 cm paired zooplankton nets (mesh size 200 mm). Double oblique hauls were conducted from top to bottom or to a maximum depth of 200 m) while the ship was steaming at 2.5 kn. A total of 43 samples per station were included in the analysis. Samples were imaged with ZooScan. Full images were processed with ZooProcess which generated set of associated features measured on each identified object (Gorsky et al, 2010). These objects were sorted following a common taxonomic guide using the web application EcoTaxa (http://ecotaxa.obs-vlfr.fr). As a sanity check, a variable number of aliquots were directly identified by light microscopy. These results permitted the description of the mean and variable components of the plankton community, their seasonal in the context of the thermohaline and transport variability in the 2010s