Assessment of the effects of sediment and oceanographic parameters on the spatial distribution of the sea urchins in the Mediterranean sea: the case of Nekor Bay (Morocco)
摘要
In this study, sea urchin specimens of P. lividus and A. lixula were collected in May 2025 from two stations in Nekor Bay, Morocco (Alboran Sea, southwestern Mediterranean). P. lividus individuals were sampled from the eastern region, and A. lixula from the western region. Biometric measurements were recorded for each specimen. Oceanographic parameters from January 2020 to May 2025 were obtained from the Copernicus Marine Service and analyzed alongside surface sediment samples collected in July 2022. Data were processed in Ocean Data View to characterize environmental conditions. P. lividus individuals were generally larger and heavier than A. lixula. Oceanographic parameters showed limited spatial variability: temperature 23–23.3 °C, salinity 36.54–36.57 PSU, pH 8.06–8.07, and total alkalinity 2.525–2.529 mmol kg−1. Nutrient concentrations were uniform, with slightly higher chlorophyll-a (0.132–0.138 mg m−3) and dissolved oxygen (247.7–248.5 mmol m−3) in the east, suggesting minor biological enrichment. Sediment analysis revealed fine sand in the west and coarser sand in the east. These findings highlight how sediment characteristics and environmental parameters influence the spatial distribution of sea urchin populations in Nekor Bay, informing ecological interpretations.