Age and growth of narrow-barred Spanish mackerel Scomberomorus commerson in the coastal waters of southern Mozambique and KwaZulu-Natal, South Africa. Issue 4 (1st December 2017)

• Record Type: Journal Article
• Authors: Lee, B; Mann, BQ
• Is Part Of: African journal of marine science. Volume 39:Issue 4(2017)
• Page Start: 397
• Page End: 407
• Publication Date: 2017-12-01
• Subjects: back-calculation -- growth estimates -- otolith ageing -- recreational fishery -- Schnute model -- Scombridae -- sex-specific growth -- tag-recapture data; Marine biology -- Africa -- Periodicals; Marine biology -- Periodicals; Marine sciences -- Periodicals; 578.7709605
• DOI: 10.2989/1814232X.2017.1397057
• Languages: English
• ISSNs: 1814-232X

Abstract

Abstract : The narrow-barred Spanish mackerel Scomberomorus commerson is one of the most important linefish species caught in KwaZulu-Natal and southern Mozambique waters, forming the basis of important commercial, artisanal and recreational fisheries. A total of 439 S. commerson were sampled along the east coast of southern Africa (KwaZulu-Natal, South Africa, and southern Mozambique) between April 2011 and March 2012. Retrospective length-at-age data observed from whole otoliths were used to compare and describe sex-specific growth. Growth rates obtained from otolith-derived data were compared with those estimated from 29 tag-recaptured fish. Overall, ages ranged from 0.48 to 14.6 years for females and 0.4 to 13.57 years for males. Otolith readings yielded an average percent error of 11.21%, lower than recorded in a previous study from the region. Marginal zone analysis provided strong evidence that one translucent and one opaque growth zone were laid down annually. Schnute growth-function parameters indicated significant differences in growth between sexes. Females approached their mean asymptotic length at a faster rate, and grew to a greater mean length-at-age, relative to males. Growth in both sexes was rapid, achieving 67.46 cm FL (females) and 65.4 cm FL (males) in their first year of life. Growth rates obtained from tag-recaptured S. commerson indicated slower growth for smaller/younger fish up until 70 cm FL after which growth was very similar to that observed from otolith-derived data. The results of this study provide accurate, validated life-history parameters for king mackerel that are important for the assessment of stock status in the region.