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Indici comportamentali di qualità dei giovanili di specie ittiche destinati al ripopolamento attivo
No full textAntipredator responses to overhead fright stimuli in hatchery-reared and wild European sea bass (Dicentrarchus labrax L.) juveniles.
No full textDifferences in the pattern of antipredator behaviour between hatchery-reared and wild European sea bass juveniles
No full textBehavioural indicators of "wildness" as useful tools for restocking: the European sea bass (Dicentrarchus labrax L.) juvenile as a study model
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Swimming activity and feeding behaviour of larval European sea bass (Dicentrarchus labrax L.): Effects of ontogeny and increasing food density.
No full textThe behaviour of European sea bass larvae reared with the mesocosm technique was analysed in relation to ontogeny and increasing food density, with a particular focus on swimming and feeding activities. The behaviour of groups of larvae (20 animals each) belonging to three age classes (10, 20 and 30 days post-hatching) was video-recorded in experimental tanks under controlled laboratory conditions.In each replicate, three different food densities, in terms of number of naupliar Artemia/l,were obtained. The videotapes analysis allowed the identification of 6 behavioural units (larval MAPs) and their quantification in terms of either frequency (number/min), or duration (percent of time spent in that activity with respect to the total time of observation). Behavioural variation was analysed in relation both to age and food density. Results revealed that swimming activity increased significantlywith age, especially between the 10 and the 20 days post-hatching, whereas resting activities decreased with age and, in some cases, also with food density. Frequency of feeding behaviour decreased with age if they were analysed singly, but when the association between aiming posture (Sigmoid-posture) and attacks was considered, results showed that these behaviours increased with both age and food density. Further, the increase of feeding efficiency with age was also confirmed by the increase in the number of Artemia nauplii/individual across the three age groups. Results are discussed in the light of both a comparative analysis conducted with the available data on the larval behaviour of other marine fish species, and their potential use for the assessment of the quality of the reared fish, also in relation to the rearing techniques
Differences in the pattern of antipredator behaviour between hacthery and wild European sea bass juveniles
No full textRelationships between relative size of sexual traits and male mating success in the Mediterranean killifish Aphanius fasciatus (Nardo, 1827)
No full textSome relationships between the relative size of secondary sexual traits and male mating success were investigated in the killifish Aphanius fasciatus (Nardo, 1827). The relative ability of a male to compete with another male for access to a ripe female was related to the relative size of male sexual traits by means of a behavioural experiment under controlled laboratory conditions. Furthermore, the covariation in the expression of sexual traits was analysed from a sample of field-collected males. Results of the behavioural experiment showed that male dominance and success were positively related to the relative height of the dorsal fin, but not to the pattern of vertical bars along body sides. Within the analysed male population, males with larger fins tended to have thinner bars, whereas there was no statistically significant correlation with bar number or with bar asymmetry. The results were discussed in terms of advantages conferred by larger dorsal fins in killifish breeding systems, and developmental constraints defining a multiple set of traits correlated to male quality were also hypothesised. © 2010 Taylor & Francis
Differences in the pattern of antipredator behaviour between hatchery and wild European sea bass juveniles
No full textOccurrence and intensity of intercohort cannibalism of post-hatching stages in the broad-nosed pipefish, Syngnathus typhle
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