Instituto Nacional Of Desenvolvimento Das Pescas Indp

Cabo, Cape Verde

Instituto Nacional Of Desenvolvimento Das Pescas Indp

Cabo, Cape Verde
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Gonzalez J.A.,University of Las Palmas de Gran Canaria | Triay-Portella R.,University of Las Palmas de Gran Canaria | Santana J.I.,University of Las Palmas de Gran Canaria | Correia S.,Instituto Nacional Of Desenvolvimento Das Pescas Indp | And 2 more authors.
Crustaceana | Year: 2017

In the present article three benthic decapods, Aristeus varidens Holthuis, 1952 (Aristeidae), Gastroptychus formosus (Filhol, 1884) (Chirostylidae) and Plesionika longicauda (Rathbun, 1901) (Pandalidae), are recorded for the first time from the Cape Verde Islands. This is the southernmost record of G. formosus, as well as the northernmost of P. longicauda ever recorded from the eastern Atlantic. Preliminary data on batch fecundity and egg size of the pandalid shrimp are provided. Studied specimens were caught in the frame of a scientific trapping survey. © Koninklijke Brill NV, Leiden, 2017.

Karstensen J.,Leibniz Institute of Marine Science | Schutte F.,Leibniz Institute of Marine Science | Pietri A.,University Pierre and Marie Curie | Krahmann G.,Leibniz Institute of Marine Science | And 11 more authors.
Biogeosciences | Year: 2017

The temporal evolution of the physical and biogeochemical structure of an oxygen-depleted anticyclonic modewater eddy is investigated over a 2-month period using high-resolution glider and ship data. A weakly stratified eddy core (squared buoyancy frequency N2 ∼0.1 × 10-4 s-2) at shallow depth is identified with a horizontal extent of about 70km and bounded by maxima in N2. The upper N2 maximum (3-5 × 10-4s-2) coincides with the mixed layer base and the lower N2 maximum (0.4 × 10-4s-2) is found at about 200m depth in the eddy centre. The eddy core shows a constant slope in temperature/salinity (T/S) characteristic over the 2 months, but an erosion of the core progressively narrows down the T/S range. The eddy minimal oxygen concentrations decreased by about 5μmolkg-1 in 2 months, confirming earlier estimates of oxygen consumption rates in these eddies. Separating the mesoscale and perturbation flow components reveals oscillating velocity finestructure (∼0.1ms-1) underneath the eddy and at its flanks. The velocity finestructure is organized in layers that align with layers in properties (salinity, temperature) but mostly cross through surfaces of constant density. The largest magnitude in velocity finestructure is seen between the surface and 140m just outside the maximum mesoscale flow but also in a layer underneath the eddy centre, between 250 and 450m. For both regions a cyclonic rotation of the velocity finestructure with depth suggests the vertical propagation of near-inertial wave (NIW) energy. Modification of the planetary vorticity by anticyclonic (eddy core) and cyclonic (eddy periphery) relative vorticity is most likely impacting the NIW energy propagation. Below the low oxygen core salt-finger type double diffusive layers are found that align with the velocity finestructure. Apparent oxygen utilization (AOU) versus dissolved inorganic nitrate (NO3 -) ratios are about twice as high (16) in the eddy core compared to surrounding waters (8.1). A large NO3 - deficit of 4 to 6μmolkg-1 is determined, rendering denitrification an unlikely explanation. Here it is hypothesized that the differences in local recycling of nitrogen and oxygen, as a result of the eddy dynamics, cause the shift in the AOU:NO3 - ratio. High NO3 - and low oxygen waters are eroded by mixing from the eddy core and entrain into the mixed layer. The nitrogen is reintroduced into the core by gravitational settling of particulate matter out of the euphotic zone. The low oxygen water equilibrates in the mixed layer by air-sea gas exchange and does not participate in the gravitational sinking. Finally we propose a mesoscale-submesoscale interaction concept where wind energy, mediated via NIWs, drives nutrient supply to the euphotic zone and drives extraordinary blooms in anticyclonic mode-water eddies. © 2017 The Author(s).

Gonzalez J.A.,University of Las Palmas de Gran Canaria | Triay-Portella R.,University of Las Palmas de Gran Canaria | Martins A.,Instituto Nacional Of Desenvolvimento Das Pescas Indp | Lopes E.,University of Cape Verde
Cahiers de Biologie Marine | Year: 2017

In the current scenario of defaunation and bioinvasion, increasing the knowledge about the composition in marine species and monitoring are an emergency need to control the biodiversity. Nearly 35 years have passed since Türkay (1982) published the decapod crustaceans of the Cape Verde islands. No checklists of decapod fauna specifically covering this area have been published since then, and an update is needed. The current list of Cape Verdean brachyuran crabs comprises 125 species, grouped in 83 genera and 40 accepted families. Additional species have been mainly recorded thanks to intensified research into deep water and description of new taxa. Anamathia rissoana and Macropipus rugosus are recorded for the first time and the occurrence/absence of some species confirmed in the area. This work summarizes all recent changes in Cape Verdean brachyurans and makes biogeographic remarks, with a comparison with the Canary Islands brachyurans. It presents a literature review and overview about the species previously recorded in the area. It still aims to be a tool to support further monitoring to identify the absence or appearance of invasive species. © 2017, Station Biologique de Roscoff. All rights reserved.

Wirtz P.,University of Algarve | Brito A.,University of La Laguna | Falcon J.M.,University of La Laguna | Freitas R.,University of Cape Verde | And 4 more authors.
Spixiana | Year: 2013

A check-list of the coastal fishes of the Cape Verde Islands is presented. The species Acantholabrus palloni, Canthigaster supramacula, Carcharhinus leucas, Chaetodipterus lippei, Corniger spinosus, Dasyatis centroura, Didogobius n. sp., Epigonus constanciae, Halobatrachus didactylus, Hemiramphus balao, Leptocharias smithii, Lobotes surinamensis, Malacoctenus n. sp., Megalops atlanticus, Mugil bananensis, Mugil capurrii, Negaprion brevirostris, Rhinecanthus aculeatus, Sardinella aurita, Sciaena umbra, Serranus heterurus, Sphyraena barracuda, Uranoscopus cadenati, and Zu cristatus are recorded for the first time from the Cape Verde Islands. We have recognized 77 previous records as identification errors or registration errors and indicate 35 other records as doubtful. Including the 24 new records, we now list 315 fish species from the coastal waters of the Cape Verde Islands. Twenty of them (6.3 %) appear to be endemic to the archipelago.

Fischer G.,University of Bremen | Karstensen J.,Leibniz Institute of Marine Science | Romero O.,University of Bremen | Donner B.,University of Bremen | And 8 more authors.
Biogeosciences | Year: 2016

Particle fluxes at the Cape Verde Ocean Observatory (CVOO) in the eastern tropical North Atlantic for the period December 2009 until May 2011 are discussed based on bathypelagic sediment trap time-series data collected at 1290 and 3439m water depth. The typically oligotrophic particle flux pattern with weak seasonality is modified by the appearance of a highly productive and low oxygen (minimum concentration below 2 μmol kg-1 at 40m depth) anticyclonic modewater eddy (ACME) in winter 2010. The eddy passage was accompanied by unusually high mass fluxes of up to 151 mgm-22 d-1, lasting from December 2009 to May 2010. Distinct biogenic silica (BSi) and organic carbon flux peaks of ∼15 and 13.3 mgm-2 d-1, respectively, were observed in February-March 2010 when the eddy approached the CVOO. The flux of the lithogenic component, mostly mineral dust, was well correlated with that of organic carbon, in particular in the deep trap samples, suggesting a tight coupling. The lithogenic ballasting obviously resulted in high particle settling rates and, thus, a fast transfer of epi-/mesopelagic signatures to the bathypelagic traps. We suspect that the two-to three-fold increase in particle fluxes with depth as well as the tight coupling of mineral dust and organic carbon in the deep trap samples might be explained by particle focusing processes within the deeper part of the eddy. Molar C :N ratios of organic matter during the ACME passage were around 18 and 25 for the upper and lower trap samples, respectively. This suggests that some productivity under nutrient (nitrate) limitation occurred in the euphotic zone of the eddy in the beginning of 2010 or that a local nitrogen recycling took place. The δ15N record showed a decrease from 5.21 to 3.11 from January to March 2010, while the organic carbon and nitrogen fluxes increased. The causes of enhanced sedimentation from the eddy in February/ March 2010 remain elusive, but nutrient depletion and/or an increased availability of dust as a ballast mineral for organic-rich aggregates might have contributed. Rapid remineralisation of sinking organic-rich particles could have contributed to oxygen depletion at shallow depth. Although the eddy formed in the West African coastal area in summer 2009, no indications of coastal flux signatures (e.g. from diatoms) were found in the sediment trap samples, confirming the assumption that the suboxia developed within the eddy en route. However, we could not detect biomarkers indicative of the presence of anammox (anaerobic ammonia oxidation) bacteria or green sulfur bacteria thriving in photic zone suboxia/hypoxia, i.e. ladderane fatty acids and isorenieratene derivatives, respectively. This could indicate that suboxic conditions in the eddy had recently developed and/or the respective bacterial stocks had not yet reached detection thresholds. Another explanation is that the fast-sinking organic-rich particles produced in the surface layer did not interact with bacteria from the suboxic zone below. Carbon-ate fluxes dropped from ∼52 to 21.4 mgm-2 d-1 from January to February 2010, respectively, mainly due to reduced contribution of shallow-dwelling planktonic foraminifera and pteropods. The deep-dwelling foraminifera Globorotalia menardii, however, showed a major flux peak in February 2010, most probably due to the suboxia/hypoxia. The low oxygen conditions forced at least some zooplankton to reduce diel vertical migration. Reduced "flux feeding" by zooplankton in the epipelagic could have contributed to the enhanced fluxes of organic materials to the bathypelagic traps during the eddy passage. Further studies are required on eddy-induced particle production and preservation processes and particle focusing. © 2016 Author(s).

Oliveira M.T.,Oceanario de Lisbon S.A. | Oliveira M.T.,University of Algarve | Santos M.N.,Instituto Portugues Do Mar E Da Atmosfera Ipma Ip | Coelho R.,Instituto Portugues Do Mar E Da Atmosfera Ipma Ip | And 3 more authors.
Journal of Applied Ichthyology | Year: 2015

Summary: This study reports weight-length and length-length relationships for selected coastal reef fish species of the Cape Verde Archipelago (tropical north-eastern Atlantic). Specimens were caught with different types of gear (long-lines, hand-lines, purse-seines and traps) during commercial fishing activities and sampled during fish market operations. A total of 8328 individuals were sampled, representing 29 species from 14 Families. This study provides the first references on weight-length and length-length relationships for five and 23 fish species worldwide, for 10 and 24 species for the Eastern Atlantic and for 12 and 26 species for Cape Verde Archipelago, respectively. Additionally, it provides revised weight-length relationships for 11 species from Cape Verde waters. © 2014 Blackwell Verlag GmbH.

Hauss H.,Leibniz Institute of Marine Science | Christiansen S.,Leibniz Institute of Marine Science | Schutte F.,Leibniz Institute of Marine Science | Kiko R.,Leibniz Institute of Marine Science | And 8 more authors.
Biogeosciences | Year: 2016

The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300-600 m depth. Here, oxygen concentrations rarely fall below 40 μmol O2 kgg-1, but are expected to decline under future projections of global warming. The recent discovery of mesoscale eddies that harbour a shallow suboxic (< 5 μmol O2 kgg-1) OMZ just below the mixed layer could serve to identify zooplankton groups that may be negatively or positively affected by ongoing ocean deoxygenation. In spring 2014, a detailed survey of a suboxic anticyclonic modewater eddy (ACME) was carried out near the Cape Verde Ocean Observatory (CVOO), combining acoustic and optical profiling methods with stratified multinet hauls and hydrography. The multinet data revealed that the eddy was characterized by an approximately 1.5-fold increase in total area-integrated zooplankton abundance. At nighttime, when a large proportion of acoustic scatterers is ascending into the upper 150 m, a drastic reduction in mean volume backscattering (Sv) at 75 kHz (shipboard acoustic Doppler current profiler, ADCP) within the shallow OMZ of the eddy was evident compared to the nighttime distribution outside the eddy. Acoustic scatterers avoided the depth range between approximately 85 to 120 m, where oxygen concentrations were lower than approximately 20 μmol O2 kgg-1, indicating habitat compression to the oxygenated surface layer. This observation is confirmed by time series observations of a moored ADCP (upward looking, 300 kHz) during an ACME transit at the CVOO mooring in 2010. Nevertheless, part of the diurnal vertical migration (DVM) from the surface layer to the mesopelagic continued through the shallow OMZ. Based upon vertically stratified multinet hauls, Underwater Vision Profiler (UVP5) and ADCP data, four strategies followed by zooplankton in response to in response to the eddy OMZ have been identified: (i) shallow OMZ avoidance and compression at the surface (e.g. most calanoid copepods, euphausiids); (ii) migration to the shallow OMZ core during daytime, but paying O2 debt at the surface at nighttime (e.g. siphonophores, Oncaea spp., eucalanoid copepods); (iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes); and (iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey-predator encounter rates, rendering zooplankton and micronekton more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 μmol O2 kgg-1. This may result in a positive feedback on the OMZ oxygen consumption rates, since zooplankton and micronekton respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline. © 2016 Author(s).

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