Age, growth and mortality of the comber Serranus cabrilla (Linnaeus, 1758) in the Eastern Atlantic

ABSTRACT

Comber is an important bycatch species in the trawl fishery both in the Mediterranean and the Atlantic. Age and growth studies have been restricted to the eastern Mediterranean and no methodologies were ever applied to ensure accuracy and precision. In this study a total of 471 otoliths from specimens ranging from 12 to 26 cm were used. Precision indices showed a high level of agreement between readers and no evidence of systematic disagreement was obtained. To estimate fish growth and due to the absence of individuals smaller than 12 cm, three approaches were used to estimate the von Bertalanffy growth parameters: whole otolith readings, back calculation and a combination of both methodologies. Akaike’s information criterion suggests that the back calculation approach was the best one for describing comber growth: TL = 25.26 [1−e^{(−0.21(t+1.72)}]. Natural mortality estimates varied between M = 0.44 year⁻¹ and M = 0.48 year⁻¹ while estimates of the fishing mortality varied between 0.12 year⁻¹ and 0.16 year⁻¹ and the exploitation rate between 0.20 and 0.27.

RESPONSIBLE EDITOR:

• Kjell Rong Utne

KEYWORDS:

• Serranus cabrilla
• comber
• otoliths
• precision estimators
• age and growth
• mortality

Acknowledgements

The authors thank Pedro Gomes and the crew of the trawler Sagittarius for providing the specimens used in this study. They also thank the contribution of two referees whose comments greatly improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Leonel Serrano Gordo http://orcid.org/0000-0002-9144-6061

Ana Neves http://orcid.org/0000-0003-3885-2738

Ana Rita Vieira http://orcid.org/0000-0002-5640-7999

Vera Sequeira http://orcid.org/0000-0001-7173-4982

Additional information

Funding

This study was partially supported by the Fundação para a Ciência e Tecnologia (FCT), under grants attributed to Vera Sequeira (SFRH/BPD/70200/2010), Rafaela Barros Paiva (SFRH/BD/80268/2011) and Ana Neves (SFRH/BD/92769/2013).