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- Social organization and endocrine profiles of Australoheros facetus, an exotic freshwater fish in southern PortugalPublication . Baduy, F.; Silva, FBV; Guerreiro, Pedro M; Canario, A.V.M.; L. Saraiva, JoãoAustraloheros facetus is a neotropical cichlid and an exotic species in the Guadiana and Odelouca basins (Southern Portugal). In this research, we aimed to characterize the main behavioural patterns and circulating hormones, 17 beta-estradiol (E-2) for females, and testosterone, 11-ketotestosterone (11KT) and cortisol for both sexes, during the formation of social groups, a crucial step in the life-history of A. facetus. A pair-breeding strategy with territorial behaviour and aggressive interactions was found, with a positive correlation between dominance and size for both sexes. There were no significant differences between non-territorial and territorial individuals in the baseline levels of hormones, but 11KT was higher in males when they became territorial, as E-2 for territorial females, while there was no clear pattern for testosterone. In contrast, cortisol was higher in non-territorial males and correlated negatively with social dominance. These results suggest that size is the main driver for social dominance and that formation of stable hierarchies result in higher circulating 11KT and lowers stress in territorial males. Related to A. facetus' behaviour, aggressiveness and biparental care may be an advantage during the invasion process of A. facetus, facilitating colonization of new habitats.
- Effect of long-term thermal challenge on the Antarctic notothenioid Notothenia rossiiPublication . Kandalski, Priscila Krebsbach; Zaleski, Tania; Forgati, Mariana; Baduy, Flávia; Eugenio, Danilo Santos; Machado, Cintia; Dmengeon Pedreiro de Souza, Maria Rosa; Piechnik, Claudio Adriano; Favaro, Luis Fernando; Donatti, LuceliaThe thermal stability of the Antarctic Ocean raises questions concerning the metabolic plasticity of Antarctic notothenioids to changes in the environmental temperature. In this study, Notothenia rossii survived 90 days at 8 degrees C, and their condition factor level was maintained. However, their hepatosomatic (0.29x) index decreased, indicating a decrease in nutrient storage as a result of changes in the energy demands to support survival. At 8 degrees C, the plasma calcium, magnesium, cholesterol, and triglyceride concentrations decreased, whereas the glucose (1.91x) and albumin (1.26x) concentrations increased. The main energy substrate of the fish changed from lipids to glucose due to a marked increase in lactate dehydrogenase activity, as demonstrated by an increase in anaerobic metabolism. Moreover, malate dehydrogenase activity increased in all tissues, suggesting that fish acclimated at 8 degrees C exhibit enhanced gluconeogenesis. The aerobic demand increased only in the liver due to an increase (2.23x) in citrate synthase activity. Decreases in the activities of superoxide dismutase, catalase, and glutathione-Stransferase to levels that are most likely sufficient at 8 degrees C were observed, establishing a new physiological activity range for antioxidant defense. Our findings indicate that N. rossii has some compensatory mechanisms that enabled its long-term survival at 8 degrees C.
- Taxonomic re-evaluation of the non-native cichlid in Portuguese drainagesPublication . Carecho, João; Baduy, F.; Silva, FBV; Guerreiro, Pedro; Saraiva, João L.; Ribeiro, Filipe; Veríssimo, AnaA non-native cichlid fish firstly reported in Portugal in 1940 was originally identified as Cichlasoma facetum (Jenyns 1842) based on specimens reported from “Praia de Mira” (Vouga drainage, northwestern Portugal). Currently, the species is known only from three southern Portuguese river drainages, namely Sado, Arade and Guadiana, and no other record has been made from Praia de Mira or the Vouga drainage since the original record. The genus Cichlasoma has since suffered major taxonomic revisions: C. facetum has been considered a species-complex and proposed as the new genus Australoheros, including many species. Given the current taxonomic re-arrangement of the C. facetum species group, we performed a taxonomic re-evaluation of species identity of this non-native cichlid in Portuguese drainages using morphological and molecular analyses. Morphological data collected on specimens sampled in the Sado river drainages confirmed the identification as Australoheros facetus. Moreover, nucleotide sequences of the cytochrome b gene obtained from specimens from Sado, Arade and Guadiana showed the existence of a single haplotype across drainages, which was 100% identical to A. facetus specimens collected in native Argentinean waters (i.e. Uruguay River). The current non-native distribution range of the species in Portugal results from human-mediated introductions across the southern drainages.