Age and growth of the Argentine hake Merluccius hubbsi Marini, 1933 in the Brazilian South-Southeast Region during 1996-2001

• Main Authors: André M. Vaz-dos-Santos, Carmen Lúcia D. B. Rossi-Wongtschowski
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Ictiologia
• Series: Neotropical Ichthyology
• Subjects: Merluccius hubbsi; Growth parameters; Otolith; Age structure; South-Southeastern region of Brazil
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252007000300017&lng=en&tlng=en

This is the first detailed study on the age and growth of the Argentine hake Merluccius hubbsi in Brazilian waters. A total of 3,651 specimens obtained from surveys and sampling landings using trawlers and long-lines in the South-Southeast Region (21ºS to 34ºS) between 1996 and 2001 were analyzed. Readings of sliced and burned otoliths were conducted on 686 individuals (397 females, 129 males and 160 young - sex not identified), identifying opaque and translucent zones. Marginal increment and edge type percentage methods were used for validation, resulting in one ring per year, formed during summer-autumn. Fish with no more than eight rings and six years of age were found, the two first rings after the core being formed during the first year. Back-calculation methods were applied to length/age data and the parameters of von Bertalanffy's growth model were fitted based on average length per ring. The value of maximum theoretical length varied between 470.27 mm and 807.40 mm; growth coefficient varied from 0.1657 to 0.3555 year-1 and the theoretical age at length zero between -1.2846 and -0.4552 years. Growth of females and males differed significantly. The techniques applied and the results obtained are discussed and compared with studies on hake conducted in Uruguay and Argentina, providing important information for the management of the species in Brazil, where it presents clear signs of overexploitation.