Population Structure of the Tub Gurnard (Chelidonichthys lucerna Linnaeus, 1758) in Türkiye Coasts Using Otolith Chemistry and Shape Analysis

Abstract

Chelidonichthys lucerna is an economically important demersal species. It is under excessive fishing pressure and yields from fisheries are in decline in Türkiye. Information about the species' population structure and habitat connections is limited. In this study, otolith chemistry and shape analyses of 160 individuals captured between February 2020 and December 2020, in the four main fishing grounds of Türkiye coasts (Black Sea/Ordu, Marmara Sea/Bandırma, Aegean Sea/Foça, Mediterranean Sea/Mersin) were investigated. Otolith morphology and chemistry (Li:Ca, Na:Ca, Mg:Ca, Mn:Ca, Fe:Ca, Co:Ca, Ni:Ca, Cu:Ca, Zn:Ca, Sr:Ca, Ba:Ca , Pb:Ca, K:Ca, P:Ca) of the individuals with similar length range (19-25 cm, TL) were evaluated by univariate and multivariate statistical analyses. The overall combination of otolith elemental chemistry and morphology techniques revealed the highest re-classification success (75%-90%) of samples to their original location and the existence of significant differences among sampling regions. When otolith shape analysis and otolith chemistry were evaluated together, linear discrimination function analyses fully discriminated C. lucerna individuals from the four sampling regions (Black Sea, Marmara, Aegean, Mediterranean). Moreover, the results of the analyses revealed that there were habitat connections among individuals from the Sea of Marmara and Aegean Sea and that the Black Sea and the Mediterranean Sea were isolated regions in terms of C. lucerna stocks. The shape and chemical signatures suggest that C. lucerna is apparently not a single stock-unit in the Turkish coasts and that these fish stocks should be managed separately for fisheries purposes.

Keywords

• triglidae
• natural tag
• sagitta
• stock discrimination
• fisheries management