Reproduction Activity of Flathead Mullet Mugil cephalus (Linnaeus, 1758) in Wild Condition in the Northeast of Algeria

Abstract The objective of the present study was to investigate variations in sperm parameters of wild Mugil cephalus (known as flathead grey mullet)during its natural spawning season in 2015, in addition to the conventional indices, gonadosomatic and hepato-somatic indices (GSI and HSI) and condition factor (K) in male and female Mugil cephalus from July 2014 to December 2015. Sperm motility was assessed by a Computer-Assisted Sperm Analysis (CASA) measuring Curvilinear Velocity (VCL), Straight Line Velocity (VSL), Average Path Velocity (VAP) and Linearity (LIN). Based on GSI, the results demonstrated that M. cephalus spawns in autumn with its peak in November. Variations in K and HSI were clearly associated with reproduction activity. Sperm quality parameters varied significantly during the spawning season. Sperm volume decreased significantly from 0.41 ± 0.33 mL on November 7 to 0.26 ± 0.22 mL on December 2, while spermatozoa concentration increased significantly from 0.35 ± 1 × 109 mL−1 to 26.48 ± 42.5 × 109 mL−1. The highest VCL (27.26 ± 1.05 μm s−1), VSL (13.40 ± 1.03 μm s−1), VAP (17.91 ± 1.08 μm s−1) and LIN (36.64 ± 1.69%) values were observed in November. The current finding provided valuable information on M. cephalus reproduction in Algerian coastal environment, particularly by revealing optimal periods for further artificial reproduction, especially concerning sperm cryopreservation.