Age, growth and reproduction of Raja miraletus (Linnaeus, 1758) (Chondrichthyes: Rajidae) of the Gulf of Gabes (Tunisia, Central Mediterranean Sea)

Age and growth of the brown ray, Raja miraletus, was estimated from ring counts on vertebral sections from 95 females (13.5-56.0 cm total length (TL)) and 85 males (13.5-58.0 cm TL) collected from the Gulf of Gabes (Central Mediterranean, Tunisia) during 2007. Marginal increment and edge analyses suggest annual band pair formation. The oldest female and male brown rays were 9 and 7 years old, respectively. Von Bertalanffy growth parameters are L8 = 69.20 cm TL, k = 0.18 year(-1) and t(0) = -0.11 years for females, and L8 = 67 cm TL, k = 0.22 year(-1) and t(0) = -1.01 years for males. Longevity estimates were 19.25 and 15.75 years for females and males, respectively. Based on life history parameters, natural mortality estimation M was in the range 0.37-0.47 for females and 0.60-0.61 for males. Males were found to mature between 28 and 43 cm TL and L-50% was estimated at 34.31 cm TL (21.91 cm DW). Females mature between 33 and 48 cm TL and reached L-50% at 41.8 cm (27.10 cm DW). Age at sexual maturity (A(50%)) was estimated at 2.7 years for males and 4.41 years for females. Females and males have an annual reproductive cycle. Mating occurred mostly through spring and summer.