A preliminary study on the age and growth of the argentine, Argentina sphyraena (Actinopterygii: Osmeriformes: Argentinidae) from the eastern Adriatic Sea

Abstract

Background. Age determination is a basic step in understanding fish biology and dynamics of fish populations. The only available data on the age and growth of argentine, Argentina sphyraena Linnaeus, 1758, a non-commercially exploited species of the family Argentinidae, was published almost half a century ago. More recent reports are limited to general biological characteristics of A. sphyraena so the main goal of our study was to fill a gap by investigating age and growth of the eastern Adriatic population of this fish. Materials and methods. Samples of the argentine were collected in the eastern Adriatic Sea, during March 2011, using a bottom trawl. We analysed sagittal otolith morphology and morphometry; the age of each fish was determined from the number of growth zones on otoliths and relations between the observed otolith age and otolith morphometrics were constructed using a power model. Mean length-at-age was described using the von Bertalanffy growth model. Results. Sagittal otoliths of Argentina sphyraena displayed alternating opaque and translucent zones. The maximum observed age was 3 years for both females and males. Females that were 2+ and 3+ years old were the most numerous in the sampled population. The estimated values of the von Bertalanffy growth model parameters were: L∞ = 17.57 cm; k = 0.40 year–1; t0 = –1.39 years. The age of the argentine can be best predicted from the otolith thickness. Conclusion. The maximum lengths and ages recorded in this study confirmed that in warmer southern latitudes, Argentina sphyraena attains a smaller maximum size. It should be emphasized that the presented model described the growth of fish ages 1–3 and therefore is probably representative only for younger age groups of argentine.