An approach to age and growth of south Atlantic swordfish (Xiphias gladius) stock

A first growth function was estimated for the South Atlantic swordfish stock. A total of 406 anal fins were collected from 2006 to 2013. Fins were classified into three types and the most common, type A, was selected. Biometric relationships among several ray section measurements and lower jaw fork length were analysed. A detailed methodological description for swordfish age interpretation has been developed. Inconclusive results have been obtained when indirect validation test, as edge type and marginal increment ratio analysis, were applied. Mean size at age and growth parameters were estimated using the Standard Von Bertalanffy growth model (VBGM) (L∞= 358.7, k= 0.092, t0= -1.929), which showed the best fit in comparison with other VBGMs

Inventari Español de Hábitat y Especies Marinos

Publicad

Guía interpretativa del Inventario Español de Hábitats Marinos

Publicad

White anglerfish (Lophius piscatorius) in northern Iberian waters and northernmost Atlantic areas: weight-length relationships and other population parameters from a decade of research

The white anglerfish (Lophius piscatorius) is a bottom-living and commercially important species for European fisheries (∼38.000 t in Atlantic waters in 2015). Weight-length relationship, weight conversion factors and condition factor for this species are estimated from a decade (2006-2015) in northern Iberian waters (ICES Div. VIIIc-IXa, southern stock) and in Celtic Seas (ICES Div. VIIb,c,h,j,k, northern stock). A total of 7219 white anglerfish were collected from commercial landings and research surveys and the total length (Lt), total weight (Wt), gutted weight with liver (Wgl) and gutted weight (Wg) were obtained. The weight-length relationships for the combined sexes were: Lt = 0.025 Wt2.853; Lt = 0.02 Wgl2.868; Lt = 0.024 Wg2.861 in Div. VIIIc-IXa, and Lt = 0.027 Wt2.826; Lt = 0.023 Wgl2.825; Lt = 0.023 Wg2.816 in Div. VIIb,c,h,j,k. The commercial landings of this species are available in gutted weight, and therefore the conversion factor (total-gutted weights) was also estimated. All these results can be used in the annual assessment of the state of both stocks in the ICES working group. The condition factor was estimated along the year for immature and mature individuals of each sex and it could provide additional information regarding the spawning season. The results are compared to the previously estimated in other studies