“…The seasonal fluctuations in metal levels in Al Hoceima coast may be due to a combination of factors, directly related to weight (reproductive cycle, sexual maturity, abundance of food and environmental conditions) [30,31], but also others, independent, such as the biogeochemical cycle change and the bioavailability of metals in the seawater [32]. Numerous investigations have indicated that physiological processes, such as the gametogenic cycle, affect the seasonal fluctuation in heavy metal contents in the soft tissues of bivalves [24,25]. However, another possible explanation for the pattern of metallic bioaccumulation in mussel tissue could be found under climatological conditions which characterize the Mediterranean basin, with hot and dry summers, and wet and rainy winters.…”