AGGRESSIVE BEHAVIOR AND INTRASPECIFIC CANNIBALISM IN LARVAE AND JUVENILES OF LAMBARI (Astyanax lacustris): CAUSES AND MITIGATING MEASURES

• Grant number: 24/20187-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2025
• End date: July 31, 2028
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Maria Célia Portella
• Grantee: Hugo Leandro dos Santos
• Host Institution: Centro de Aquicultura (CAUNESP). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

In Brazil, aquaculture is growing exponentially and expanding the production of small fish species. The lambari or tetra (Astyanax lacustris) stands out both for supplying the market for human consumption and for recreational and commercial pourpose as live bait for fishing. However, the occurrence of cannibalism among lambari larvae and juveniles is a challenge frequently reported by commercial producers, primarily influenced by feeding frequency, population density, and stress. Studies indicate that several strategies are effective in significantly reducing aggressive behavior and cannibalism in larvae and juveniles such as feeding management, the supplementation of stress-reducing agents or its precursors in the diet and the use of colored extracts in the water to increase turbidity and decrease visual contact between individuals. The aim of this study is to evaluate the effects of stocking density and feeding frequency on the incidence of cannibalism during the early life stages of lambari and to assess mitigating measures such as the use of tryptophan, cannabidiol, tyrosine, and aqueous extract of Terminalia catappa for controlling aggressive behavior and cannibalism. Survival rates, cannibalism rates, growth rates, as well as larval behavior, stress challenge of transportation, gene expression, and blood parameters will be analyzed. These approaches aim to understand and mitigate aggressive behavior and cannibalism in lambari early stages, thereby improving its farming and production and providing basis to advance studies in other commercially relevant species.