This study is aimed to pinpoint the morphometrics, state of exploitation dynamic in order to assess the P. mauritanicus (Gruvel, 1911) stock. Specimens were caught by trawlers operating in Béni-Saf Bay. In total 121 individuals were collected: 60 males (49.58%) and 61 (50.41%) females, χ2 test (p<0.05) didn’t show any significant difference between the two sexes. FISAT II software was used to estimate growth parameters, recruitment, mortality and exploitation rates. Total length-total weight, total length, carapace length equations parameters for the entire population were respectively TW=0.0363*TL2.858, Log TL = 0.802*Log CL+ 0.631 indicating a negative allometry growth. The parameters of Von Bertalanffy were: L∞ =32.03 cm, K=0.18 yr-1and t0= -0.16 year-1. Total mortality was estimated Z = 0.760 yr-1, natural maturity M=0.458 yr-1, fishing mortality F=0.302 yr-1 and exploitation ratio E=0.397 reflecting a situation near the full exploitation of the resource.