The aim of this study is to characterize the physicochemical parameters of the waters of certain continental wetlands and to determine the fish population diversity of this aquatic habitat in Mauritania. Physico-chemical analyses carried out in 2015-2016 (wet-fresh, hot-dry) suggest the qualities of good water, favorable to aquatic life at any time of the year. The highest values were recorded in the warm season (from 26.6 to 34.4 °C for the temperature, from 8 to 9.2 for the pH, from 170 to 591 μs/cm for the conductivity, from 3, 23 to 8.2 mg / l for dissolved oxygen and 169 to 590 mg / l TDS). The lowest values were found in the cold season (from 18.0 to 27.0 ° C for temperature, from 7.5 to 9.0 for pH, from 99.5 to 358 μs/cm for conductivity, 2.70 to 4.80 mg/l for dissolved oxygen and 100 to 360 mg/l of TDS). The establishment and development of biodiversity in these wetlands were at their peak during the hot and dry periods. 15 species belonging to 8 families were identified in these sites where there is a significant fishing activity. It is during this period that fish biodiversity and fishery potential increase as water decreases under the pressure of evaporation, infiltration and anthropozoogenic consumption. The ecosystem services of these continental wetlands, which survive the impacts of climate change, require urgent management, preservation and development measures.

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Histamine is a security issue in food safety as an indicator of the freshness of consumed fish product; that is why we aimed in this study to determine the histamine content in 7 fish species (Scomber japonicus; Sarda sarda; Sardinella aurita; S. maderensis; Ethmalosa fimbriata; Pomatomus saltatrix and Trachurus trachurus). Hundred and eight frozen and fresh pelagic of scombroid and non-scombroid species were collected from the Nouakchott fish market (Mauritanian Atlantic coast) in different period of 2020 and 2021. Histamine was quantified by the technique of high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). Histamine was detected in all analyzed fresh and frozen species and varied from 4.21 to 201.60 ppm. All evaluated fresh fish species (S. aurita; S. maderensis; E. fimbriata; P. saltatrix and T. trachurus) were conform to the FAO/WHO and the European commission regulations. Regarding investigated frozen fish species (S. aurita; S. japonicus and S. sarda); the scombroid species (S. japonicus and S. sarda) were all under the set limits; however, even its more likely for scombroid fish to develop histamine, our results showed that histamine exceed the limit in one sample of non-scombroid fish (S. aurita). No significant variation in histamine levels between scombroid and non-scombroid fish species was obtained; thereby, the study showed that fish product commercialized at the Nouakchott fish market have a good quality and safe for human consumption.