National Institute of Halieutic Research

Tangier, Morocco

National Institute of Halieutic Research

Tangier, Morocco
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Abdelouahab H.,Hassan II University | Abdelouahab H.,National Institute of Halieutic Research | Berraho A.,National Institute of Halieutic Research | Baibai T.,National Institute of Halieutic Research | And 3 more authors.
Chinese Journal of Oceanology and Limnology | Year: 2017

A study on the assemblage composition and vertical distribution of larval fish was conducted in the southern area of the Moroccan Atlantic coast in Autumn 2011. A total of 1 680 fish larvae taxa were identified from 21 families. The majority of the larvae were present in the upper layers. Clupeids were the most abundant larvae taxa followed by Myctophidae, Gadidae and Sparidae, hence the larval fish assemblages (LFA) were variable in diff erent depth layers. Total fish larvae showed a preference for surface layers, and were mainly found above 75 m depth, with some exceptions. The maximum concentration of fish larvae was concentrated up to 25 m essentially above the thermocline, where chlorophyll a and mesozooplankton were abundant. Spatially, neritic families were located near the coast and at some off shore stations especially in the northern part, while oceanic families were more distributed towards off shore along the study area. Cluster analysis showed a segregation of two groups of larvae. However, a clear separation between neritic families and oceanic families was not found. Multivariate analysis highlighted the relationship between the distribution of larvae of diff erent families and environmental parameters. Temperature and salinity seem to have been the factors that acted on associations of fish larvae. Day/night vertical distributions suggest there was not a very significant vertical migration, probably due to adequate light levels for feeding. © 2017, Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag Berlin Heidelberg.

Omar M.B.,National Institute of Halieutic Research | Omar M.B.,University of Cádiz | Mendiguchia C.,University of Cádiz | Er-Raioui H.,Abdelmalek Essaadi University | And 5 more authors.
Environmental Earth Sciences | Year: 2015

The heavy metal concentrations (Al, Fe, Ti, Mn, Zn, Cd, Co, Cr, Ni, Pb and Cu) in sediment samples collected from the Moroccan Mediterranean coast were studied. The heavy metal concentrations obtained were similar or relatively low when compared with other Mediterranean zones. To assess their distribution and distinguish between their natural and anthropogenic sources, the enrichment factor (EF) index was applied. Consequently, minor enrichment by Cd, Cu, Fe, Mn and Pb was observed. The effects on aquatic organisms were established using sediment quality guidelines (SQGs). As a result, Cu concentrations were above the interim sediment quality guidelines (ISQG), Ni and Pb presented concentrations above the effects range low (ERL) while Cr was above the probable effect level (PEL) in some sampling points. In addition, a principal component analysis was performed showing that the distribution of metals in the study area seems to be influenced by both natural and anthropogenic sources. Nevertheless, the analysis of mineralogical composition has allowed the identification of a natural source as the most probable origin of some elements, such as Ni and Mn, related mainly to the geological background. In contrast, Fe, Cr, Co and Pb could be related to both natural and anthropogenic activities in the area while Cd and Cu seem to have an anthropic origin. © 2015, Springer-Verlag Berlin Heidelberg.

Tovar-Sanchez A.,Campus Management | Tovar-Sanchez A.,CSIC - Mediterranean Institute for Advanced Studies | Basterretxea G.,CSIC - Mediterranean Institute for Advanced Studies | Ben Omar M.,National Institute of Halieutic Research | And 6 more authors.
Estuarine, Coastal and Shelf Science | Year: 2016

We analyzed dissolved nutrient, trace metal and vitamin (B-vitamins and methionine) concentrations in the lower course of the Moulouya River (MR, Morocco) and its estuary. The flow of this African river has changed drastically (a reduction of almost 50%) in the last 50 years due to the regulation of the river flow through dams and alterations of the course constructed to satisfy population necessities and growing agricultural requirements. Consequently, it has produced a remarkable increase in nitrate concentrations (up to 270 μM) and alteration of N:P ratios within the river, as well as a reduction of overall P and Si efflux to nearby coastal waters. Despite the historical mining activities in the upper MR, concentrations of Pb, Zn and other metals in sediments and waters do not display significant contamination as compared with other Mediterranean rivers, mainly due to the retention by dams of upstream metal contamination. Mean concentrations of dissolved B-vitamins in the river showed lower levels (13-55% lower) than those in coastal waters and hence the river does not represent an important B-vitamin source. © 2016 Elsevier Ltd.

Ben Omar M.,National Institute of Halieutic Research | Ben Omar M.,University of Cádiz | Mendiguchia C.,University of Cádiz | Garcia-Vargas M.,University of Cádiz | Moreno C.,University of Cádiz
Desalination and Water Treatment | Year: 2016

This work aims to study the use of a spiral supported liquid membrane (SLM) to extract lead (Pb) from seawater matrix using the di-(2-ethylhexyl) phosphoric acid (DEHPA) dissolved in kerosene as carrier. In this regard, several physical and chemical parameters which could affect Pb extraction (sample pH, sodium acetate buffer, HNO3 concentration in stripping solution, masking agent effect, flow rate, filter porosity, and configuration of the SLM cell) were studied. In this sense, the permeability parameter was selected to probe the system efficiency. The optimal preconcentration factor was found to be of 14.2, after 2 h under the following conditions: sample pH equal to 4.7 buffered until a 0.08 M of sodium acetate, DEPHA concentration fixed at 0.21 M and HNO3 concentration of 0.23 M in stripping solution. Besides, SLM filters were analyzed by electron microscopy after each period of 2 h and several microparticles and other deposits in form of a thin layer were observed in the polymeric support. © 2015 Balaban Desalination Publications. All rights reserved.

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