Marine circulation impact on the solid waste spatial distribution in the Moroccan Atlantic seafloor

Rachida HOUSSA, Ismail BESSA, Karim HILMI, Safia LOULAD, Abdellatif BOUMAAZ, Abdelmajid DRIDI


This study analyses the impact of oceanic circulation on the spatial distribution of seafloor marine debris, in particular plastics, and the identification of high spot areas, which could be the subject of a management plan development for the preservation of marine habitats and fishery resources. The marine debris data analyzed by the GIS tool come from four trawl surveys carried out, between Cape Spartel and Cape Blanc, by the scientific research vessel of the National Institute of Fisheries Research (INRH-Morocco), during the period 2011-2018. Concerning the oceanic circulation, we used the monthly data of sea surface velocity provided from the GLORYS12V1 product of the CMEMS global ocean eddy-resolving, with 1/12° horizontal resolution. By weight, 86.5% was composed of artificial Polymers (fishing nets and plastic), Metal, and Glass. Fishing activity was the source of 94% of these polymers macro-debris. Fishing nets, metal, and Glass are concentrated in small areas, respectively 23%, 21%, and 0.6% of trawling area. At the same time, plastic covers 92% of the prospected surface with an intense concentration in the southern part characterized by a maximum of ocean circulation that can move plastic with low density from their source areas for kilometers before degrading and sinking in the seafloor.


Marine debris; seafloor; marine circulation; GIS; Moroccan Atlantic Ocean

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