engleski

Geometric morphometrics reveals sexual shape dimorphism in bogue Boops boops

The bogue, Boops boops, is one of the most common bycatch species in the commercial purse seine fishery and one of the most important species used as baitfish feed for tuna farming. It also fulfills important ecological roles as it represents an intermediate link between large predators and components of the zooplankton in the marine food web, and mitigates the environmental impacts of fish farms by absorbing much of the particulate waste produced during farming. Although it is a commercially important species in the Adriatic Sea, many aspects of its biology are still unknown. The aim of the present research was to investigate morphological traits of species from natural habitats (WO) and from aquaculture pressured environments (FA), i.e. tuna farms where large populations reside throughout the year. Tuna farms provide additional structural complexity in the water column due to sea cage infrastructure, availability of food through tuna feeding losses, and high hydrodynamic complexity, making them attractive to wild fish. Landmark-based geometric morphometrics were used to analyze body shape and examine allometric patterns of shape change with increases in total length. Although populations differed in size composition, the test for homogeneity of slopes revealed nonsignificant group allometry, suggesting that bogues change shape similarly as they increase in length at WO and FA environments. Phenotypic trajectory analysis revealed the presence of sexual shape dimorphism in bogue along the eastern Adriatic, with males having a deeper body and slightly larger head profile compared to females. Females from FA environments were bulkier compared to females from the wild, while WO and FA males had similar body shape characteristics. Variation patterns in sexual shape dimorphism between and within populations were recorded both in the wild and farm-associated environments. Despite the complex interplay of local biotic and abiotic interactions affecting phenotypic traits of bogue populations in the coastal areas of the eastern Adriatic, shape differences between males and females persist. However, further studies are needed to determine the temporal stability of the observed sex differences in response to climate change and aquaculture-pressured environments.

geometric morphometrics, bogue, sexual shape dimorphism, morphology

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