Survival analysis as a tool for breeding management of Nile tilapia in an intensive system

Survival analysis has proven to be a robust tool for studies in humans, and recently, it has been adopted in studies with animals, but very little in fish. The production of uniform fingerlings has been one challenge of aquaculture, influenced by the use of the efficient breeders. We aimed to present, for the first time in aquaculture, a survival analysis as a tool for decision-making by using the relationship between the main morphometric traits and the spawning time of Nile tilapia females up to 28 days after mating in an intensive system. We used 78 females and 26 males from which ten traits were evaluated. A check was made for the presence of eggs in the female mouth (spawning) every seven days until the final twenty-eight days. Confirmation of eggs was defined as uncensored data (C = 1) and absence of eggs as censored (C = 0). The Cox proportional hazards ratio and Kaplan-Meier models were adjusted to analyze the data. Females with a standard length of 19.19 cm (small group) and males with a weight of 259.14 g (small group) reproduced early, being more adapted to 1000 L tanks in a recirculation system. Less heavy egg masses were also related to early spawning. Therefore, the traits, standard length of the female, egg mass weight, and male weight, affected the presence of eggs up to 28 days and should be used as selection criteria for early breeders. Besides, the survival analysis was accurate as a tool for tilapia breeding management in an intensive system.

Automated summary

Survival analysis was applied for the first time in aquaculture to analyze the relationship between morphometric traits and spawning time in Nile tilapia females. The study revealed that the standard length of the female, egg mass weight, and male weight affected the presence of eggs up to 28 days, and could be used as selection criteria for early breeders. The survival analysis proved to be an accurate tool for tilapia breeding management in an intensive system.