The growth of monkfish Lophius vomerinus in Namibian waters, with a comparison of otolith and illicia methods of ageing

Ground and sectioned otoliths and sectioned illicia were used to age monkfish, Lophius vomerinus, in Namibian waters. Of the structures investigated, age estimates from the sectioned illicia were found to be the most precise as they had the lowest average percent error and coefficient of variation. Growth was subsequently modeled using the age estimates obtained from the illicia. Growth in length and weight as a function of age was best described by the von Bertalanffy growth model as L(t) (cm TL) = 72.29 (1-e-0.14(t+ 0.30)) and W(t) (kg) = 3.96 (1 - e-0.18(t+0.10))2.99 for males, and L(t) (cm TL) = 111.98 (1 - e -0.08(t+0.36)) and W(t) (kg) = 6.92 (1 - e-0.18(t-0.64))3.03 for females. This study revealed that L. vomerinus is a relatively slow-growing and long-lived species with a life span in excess of 10 years.