A previous study that explored the age and growth of red steenbras Petrus rupestris (Valenciennes, 1830), a large sparid (family Sparidae, seabreams or porgies) endemic to South Africa and reported to approach 2 m in length, provided estimates as a moderately slow-growing species with a maximum age near 30 years. The stock is considered collapsed and a fishing moratorium was imposed in 2012, resulting in this species being assessed as Endangered by the IUCN. One consideration in addressing population status is validation of life-history traits. In this study, estimates of age for red steenbras from thin-sectioned otoliths were reassessed visually in terms of both the original ages and revised estimates using a different age-reading pattern. The revised ages exceeded the original ages by up to 30 years, with a maximum estimated age of 55 years from a well-defined otolith section that provided a basis for the revised age-reading procedure. Bomb radiocarbon (14C) dating revealed there was an offset in the timing of the 14C rise on the Agulhas Bank that, when coupled with considerations for regional oceanography, provided support for the revised age-reading pattern and an estimated longevity that exceeds 50 years. These findings were further supported by the fortuitous recapture of a tagged red steenbras that was at liberty for 22 years.

Published Article: https://doi.org/10.2989/1814232X.2018.1520148 

Photographs of a transverse cross-section of a sagittal otolith from a red steenbras Petrus rupestris that was aged to 55 years (sample PeRu-05). The fine growth-zone pattern was well-defined in this otolith section and exemplifies the revised age-reading pattern used to age the other fish in this study. The top panel shows how the annual pattern can be obscured by opaque regions that show little or no evidence of growth-zone structure. The lower panel is a more magnified view of the same cross-section that was used as the ‘Rosetta Stone’ in the age reading of all otolith sections 

Micromilling the otolith core from the whole adult otolith. Extracted powder was used for 14C assays and bomb radiocarbon dating. All extraction were made with a New Wave Research micromilling machine (Elemental Scientific Lasers, Bozeman, MT, USA; http://www.nwrlasers.com/milling/micromill/).