Abstract

Accurate age information is foundational for calculations of growth and mortality rates in fish (Campana 2001). Age estimates are critical inputs for contemporary stock assessments, which rely heavily on age composition, growth estimates, age-based reproductive parameters and estimates of natural mortality for the fishery stocks. The U. S. South Atlantic red porgy (Pagrus pagrus) stock is presently overfished and undergoing overfishing, and stock recovery has not been achieved through recent management efforts (SEDAR 2020). After two southeastern U. S. laboratories submitted data for the first Southeast Data, Assessment and Review process (SEDAR; SEDAR, 2002), it was discovered that the age readings were not consistent between the labs. One laboratory read the otoliths whole, and the other read sections from the otoliths. Ages from reading the sectioned otoliths were biased high by approximately 0.5 years compared to the readings from whole otoliths. In addition, the oldest fish, >12 years, were underaged when reading whole otoliths compared to the sections. Thus, an age validation study of red porgy was undertaken to determine if the opaque zones, presumed annuli, were formed once per year and to identify the first annulus.

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