The role of stress coping style in reproduction and other biological aspects in the aquaculture species, senegalese sole (solea senegalensis) and gilthead seabream (spaurus aurata)
- Autores: Zohar Ibarra Zatarain
- Directores de la Tesis: Neil Duncan (dir. tes.), Joan Carles Balasch (tut. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2015
- Idioma: inglés
- Tribunal Calificador de la Tesis: Lluís Tort Bardolet (presid.), Mercedes Blazquez Peinado (secret.), Marie-Laure Bégout (voc.)
- Materias:
- Enlaces
- Resumen
Individuals of a same population consistently differ in their behavioural strategies to cope with stressors, commonly labelled as stress coping styles (SCS). SCS are typically characterized by two extreme behaviours: proactive and reactive. Proactive fish have been recognized to have higher activity in novel situations, to be more impulsive in decision making, to take higher risk when facing a potential danger, to be novelty seekers and to show lower glucocorticoids levels than reactive fish. Numerous studies have reported that SCS influence important biological aspects in fish, such as growth, health, resistance to diseases, welfare and reproduction. Thus, the present study aimed to characterize SCS in Senegalese sole (Solea senegalensis) and gilthead seabream (Sparus aurata) to: i) establish some reliable and operational SCS tests to characterize behaviours in Senegalese sole juveniles and breeders (Chapter 2); ii) determine whether SCS were repeatable and consistent over time and across contexts in Senegalese sole juveniles and breeders (Chapter 3) and gilthead seabream breeders (Chapter 6) and whether SCS differed between Senegalese sole juveniles with and without gametogenesis (Chapter 3); iii) evaluate whether reproduction (spawned/did not spawn), sex (males/females) and origin (wild/hatchery-reared) were related to proactive or reactive SCS in Senegalese sole (Chapter 4) and gilthead seabream (Chapter 6); iv) assess the influence of four different dietary emulsions for Artemia enrichments (based on cod liver, soybean, olive oil and linseed oil) on Senegalese sole larvae behaviour (Chapter 5); v) describe the spawning behaviour of gilthead seabream (Chapter 7). Three SCS individual tests (restraining, new environment and confinement) were selected that efficiently characterize SCS of Senegalese sole juveniles and breeders into two clusters of individuals differing in activity rates, latency to explore novel environments, risk taking and glucocorticoids levels. The selected tests are operational for aquaculture farms, since they are easy to perform, can be applied in large number of fish in a relative short time period and do not require special skills to be interpreted. Additionally, these tests explained over 70% of total behavioural variance, were cross-context correlated and identified two axes of personality defined as ¿fearfulness-reactivity¿ and ¿activity-exploration¿. Senegalese sole and gilthead seabream showed high intra-individual behavioural repeatability over time (from ¿ = 0.989, P < 0.001 to ¿ = 0.704, P = 0.047), high correlations over time (from intra-class correlations ICC = 0.978 to ICC = 0.285) and high correlations between tests (from R = 0.285, P = 0.035 to R = 0.939, P = 0.001) or across context. Senegalese sole juveniles starting gametogenesis showed higher activity, risk taking predisposition and produced lower glucocorticoids than fish without gonadal development; being classified as more proactive than fish without gametogenesis. In gilthead seabream, proactive SCS were significantly and positively associated with the reproductive success and behaviours of males were related with proactive SCS, while those of females with reactive SCS. On the contrary, SCS of Senegalese sole were not linked to spawning success, sex or origin, suggesting different life strategies for both fish species that led to different SCS tactics. Senegalese sole post-larvae showed defined proactive and reactive SCS from early ontogenesis and oils enrichments influenced SCS and risk disposition of larvae (e.g. cod oil induced proactive SCS, while vegetable oils reactive traits). Finally, the spawning behaviour of gilthead seabream was characterized by two specific patterns: a pre-spawning behaviour (schooling and coordinated swimming patterns) and a spawning behaviour stricto sensu (aggregations, courtships and spawning rush) and pair-spawning (71.6%) were more frequent than group-spawning (28.4%). The findings of this study provided valuable information to the industry for the management of these two aquacultured species that ultimately could improve welfare and production.
