Growth, age estimation and corroboration of northeast Atlantic chub mackerel (Scomber colias) in northern Iberian waters: a first attempt.

• Main Authors: Navarro, María Rosario, Landa, Jorge, Villamor, Begoña, Domínguez-Petit, Rosario
• Format: Report
• Language: English
• Published: 2021
• Subjects: Pesquerías; Centro Oceanográfico de Santander; Scombridae; Atlantic Ocean; length frequency analysis; Bhattacharya; direct age estimation; back-calculation; growth curve; otolith edge analysis; fish; growth; corroboration; Northeast Atlantic
• Online Access: http://hdl.handle.net/10508/12169; http://hdl.handle.net/10261/326905

Updated information on growth of Atlantic chub mackerel in several areas of its distribution is required for the first stock assessment. Its growth pattern in Northern Iberian waters (2011-2017) is here analyzed with different approaches: those based on otoliths analyses (direct age estimation-DAE, back-calculation-BC and otolith marginal analyses) and those based on length frequency analyses (Bhattacharya, SLCA and PROJMAT methods). Two main different growth patterns are obtained, a "slow" one based on DAE, BC and LFDA from surveys; and a "fast" one based on Bhattacharya and LFDA from commercial landings. The divergence between both patterns begins to be evident at age 3 and older. Otolith marginal analyses that show an annual periodicity in the formation of the hyaline and opaque edge, the unimodal distribution of the annuli radius and the similarity of the back-calculated mean lengths to those obtained by DAE, support the age estimation criteria used in our analysis. The VBGF growth parameters (L∞=45.34, k=0.28, t0=1.18) obtained by otolith age estimation are available for the upcoming stock assessment process.