Study of the growth of blue barbel (Pterocapoeta maroccana) in the Oued Oum Errabia River (Morocco)

¹ Applied Geoscience Research and Development Laboratory, Abdelmalek Essaâdi University, Faculty of Science and Technology, Tangier, Morocco.
² Expert consultant in Aquaculture, Morocco.
³ Ichthyology Laboratory, National Center for Hydrobiology and Fish Farming (CNHP), Azrou, Morocco.
⁴ Fisheries Laboratory, Regional Center of the National Institute for Fisheries Research (INRH), Agadir, Morocco.
⁵ Marine Environment and Natural Hazards Research Team, Abdelmalek Essaâdi University, Faculty of Science and Technology, Tangier, Morocco.

Abstract

The blue barbel (Pterocapoeta maroccana, Günther 1902) is an endemic Moroccan species classified as Critically Endangered (CE) by the international union for conservation of nature (IUCN) and Data Deficient (DD), [1,6]. This study aims to characterize its growth to support conservation and management efforts. A total of 314 individuals were sampled in the upper Oued Oum Er-Rabia River between November 2022 and May 2024. Growth was analysed using scalimetry and modelled with the Von Bertalanffy Growth Model. Asymptotic length (L_∞) and growth coefficient (K) were estimated at 402.8 mm and 0.201 yr⁻¹ for males, 463.7 mm and 0.145 yr⁻¹ for females, and 566.9 mm and 0.106 yr⁻¹ for combined sexes, indicating faster growth in males and larger asymptotic size in females. The length-weight relationship showed isometric growth in males (b = 3.00) and negative allometry in females (b = 2.91) and combined sexes (b = 2.98). These results provide key biological reference parameters for the conservation and sustainable management of this endangered species. These findings provide an important basis for biological knowledge of the species and may contribute to the development of appropriate management and conservation strategies.