Age determination, growth and otolith shape analysis of Lepidotrigla cavillone from Sardinian and Sicilian waters (Mediterranean Sea).

Abstract

The large-scaled gurnard Lepidotrigla cavillone (Lacepède, 1801) is heavily affected by trawl fisheries targeting more economically valuable species. This species plays a key role in the food web and its potential collapse could negatively affect commercially exploited species. To date, few studies have attempted to provide needed life-history information for this species' stock status evaluation. With this in mind, we collected the otoliths of 470 specimens caught along the coasts of the two larger Mediterranean islands (271 specimens in Sardinia and 199 in Sicily). Age readings showed good reproducibility (index of average percent error = 11.4%, reading agreement 86.7%). For the first time, age-at-length data from this species were employed in a multi-model inference analysis. Von Bertalanffy's function outperformed the other examined models in terms of fitting the observed data. In both regions, there were no major differences in growth between sexes. The species exhibited a relatively rapid growth rate while having a short life span (3.5 years maximum recorded age in both locations). The obtained growth parameters for combined sexes were L_∞ = 14.02 cm (TL), k = 0.45, t₀ = -1.02 and L_∞ = 11.76 cm (TL), k = 0.62, t₀ = -1.43 in the Sardinian and Sicilian Seas, respectively. Shape analysis revealed that otolith morphology might distinguish between Sardinian and Sicilian populations, which warrants further investigation. The reconstructed otolith outlines differed significantly between the two sampled locations. These morphological discrepancies are most likely due to a mix of genetic and environmental factors.