Penaeus kerathurus is an important species for the fishery, thanks to its high nutritional and economic value. Therefore, this study attempts to determine the length distribution, length-weight relationship, age composition, growth parameters, and mortality rates of a population of P. kerathurus. The material was monthly collected from commercial fishermen in and around Karabiga and the Gulf of Erdek in the Sea of Marmara, between May 2018 and April 2019. The carapace length-weight relationships were calculated as W = 0.0023 x CL2.57, W = 0.0036 x CL2.46, and W = 0.0026 x CL2.56 for the females, males and both sexes combined, respectively. The population studied was distinguished into four age groups, and the t(max) (= maximum theoretical age) was found to be reached at 11.9 year. The growth parameters were observed to be L-infinity = 60.9 mm; K = 0.24 year(-1), and t(0) = -0.58 year. The rates of total mortality (Z), natural mortality (M), fisheries mortality (F), and exploitation (E) were calculated to be 1.32, 0.43, 0.89, and 0.67, respectively. The results showed that P. kerathurus suffers from a heavy fishing pressure in the sampled area.