AEI prepress abstract  -  DOI: https://doi.org/10.3354/aei00294

Interactions between wild gilthead seabream Sparus aurata and tuna farms in the Adriatic Sea: morphological and ecophysiological fish adaptations

Igor Talijančić, Tanja Šegvić-Bubić*, Iva Žužul, Tomislav Džoić, Jasna Maršić-Lučić, Leon Grubišić

*Email: tanja.segvic@izor.hr

ABSTRACT: Morphological and ecophysiological traits of gilthead seabream Sparus aurata were used to assess the degree of phenotypic adaptation of the species to tuna farm inherent environmental conditions by comparing them to individuals of farmed and wild origin. Geometric morphometrics revealed clear body shape differentiation amongst the studied origins, whereby significant differences were noted in head profile and the anterior-body region of the fish. Morphological resemblance was recorded among gilthead seabream associated with tuna farms, indicating that they share the characteristics of a syntonic population. Change in reproductive investment strategy was observed in individuals from farm-associated origin displaying the highest gonadosomatic index but lowest condition in comparison to their farmed and wild counterparts. Multinomial logistic regression revealed that sex change from male to female with increasing length was more pronounced in farm-associated fish than in the other 2 observed origins. These findings demonstrate a significant influence of environmental factors inherent to tuna farms on the phenotypic characteristics of gilthead seabream, providing the basis for further research in revealing the ecological role of tuna farms on local marine populations.