Morocco is one of the four regions in the world known for the richness of its fish resources in its coasts (through upwelling). The upwelling phenomenon is the origin of high biological productivity of the regions which results in a strong richness of the pelagic resources (sardines, anchovies, mackerel, etc.). These species were defined as fish living in the sea between the surface and 200 meters deep and characterized by significant horizontal and vertical migration in coastal waters [1]. They make up the largest share of global marine catch and they represent quantitatively the main exploited resources, and account for almost 80 % of catches [2,3]. The socioeconomic importance of sea fishing requires managers to strengthen the biological studies necessary for the evaluation of these resources in order to allow fishermen to make the most of natural stands on one hand, and to safeguard stocks by appropriate regulatory measures on the other hand. The anchovies Engraulis encrasicolus Linnaeus, 1758 are an essential element of food chain [4]. Little is known about the biology of this species in the Atlantic waters of Morocco. It is generally admitted the existence of one unique stock for North West Africa, which extends from Morocco to Sierra Leona. Nowadays, the occurrence of different modal classes detected in acoustic surveys carried out in Moroccan and Mauritanian waters raises out the possibility of the existence of different stocks [5]. Most of the research on the ecology of this species was performed in the northern Mediterranean Sea [6][7][8][9], the Black Sea and the Azov Sea [10][11][12], the Adriatic Sea [13,14] or the Bay of Biscay [15][16][17][18]. Despite the significant economic importance of this species along the North African Atlantic coast, little information is known either on its ecology or biology. Populations of small pelagic fish, such as sardine and anchovy, show evidence of important natural fluctuations in their abundance [19,20]. These fluctuations seem to be related, among other factors, to climate variability [21] or habitat conditions [9]. Growth and reproduction are two important parameters in fish population dynamics. Therefore, the present paper is focused on the study of E. encrasicolus reproduction and growth; particularly sex-ratio, gonado-somatic index, condition factor and the size at first maturity were studied. Maarif, B.P. 5366, Casablanca, Morocco. 3 National Fisheries Research Institute, Sidi Abderrahmane Road, Equestrian Club Ould Jmel, B.P. 20050, Casablanca, Morocco Abstract A study on the sexual cycle, of the European anchovy, the pelagic fish, Engraulis encrasicolus (Clupeiformes, Engraulidae), was carried out in the Central Atlantic Moroccan coast in the period between January 2013 and December 2013. This work represents the first attempt to investigate the reproductive features of the E. encrasicolus population in this area. The sex ratio for all fish (1:1.32) was in favour of females. The macroscopic examination of the gonads showed that this specie is matu...
BackgroundPolycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. Environmental pollution of fish is a topic of rising attention in Morocco. However, only few studies have been carried out so far, describing the potential threat of organic pollution to Moroccan aquatic ecosystem. Two polycyclic aromatic hydrocarbon (PAH) metabolites, 1-hydroxypyrene (1-OH-Pyr) and 1-hydroxyphenanthrene (1-OH-Phen), were identified and quantified from the bile of 18 European eels (Anguilla anguilla), 7 Moray (Muraenidae), and 28 Conger eels (Conger conger) collected from Moulay Bousselham lagoon and Boujdour coast. The bile metabolites were separated by high-performance liquid chromatography with fluorescence detection. The present study aims to compare the levels of PAH metabolites in fish from the lagoon and the open sea and to compare levels of PAH metabolites in different fish species.ResultsThe major metabolite present in all fish was 1-hydroxypyrene (
Different concentrations of four metals namely copper, lead, chrome and cadmium were evaluated in crayfish Procambarus clarkii tissues (carapace, flesh) for a six-month period, from March to August 2013 in the Rharb of Morocco (Lagoon Merja Zerga and Nador canal). The determination of heavy metals was carried using atomic absorption spectroscopy Varian VV20. The results obtained revealed a metal's contamination of Procambarus clarkii in both sites. Concentrations of heavy metals examined Procambarus clarkii carapace ranged as follows: Merja Zerga (Pb 2.07-6.7 μg/g; Cu 2.9-9.97 μg/g; Cr 0.89-14.22 μg/g dry weight) and Nador canal: (Pb 0.08-7.8 μg/g; Cu 3.40-9.3 μg/g ; Cr 0.87-3.5 µg/g dry weight). Concentrations of heavy metals found in flesh were as follows: Merja Zerga (Pb 0.02-5.25 µg/g; Cu 9.58-23.59 µg/g; Cr 0-2.71 µg/g dry weight) and Nador canal (Pb 0.06-6.81 µg/g; Cu 9.5-37.20 µg/g; Cr 0-3.23 µg/g dry weight). The distribution of those metals in Procambarus clarkii shows high levels of contamination for lead, copper and chrome with an absence of cadmium in both sites (Merja Zerga and Nador canal). The concentrations differed in carapace and flesh.
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