Traits for Improvement. Developers of GIFT envisaged breeding a general purpose, faster growing strain of Nile tilapia suitable for a wide range of farm environments, with sufficient genetic variability for subsequent selection for other traits. Therefore, the only trait continuously targeted for improvement was harvest weight at 90 or 120 days. There were some limited attempts to select for later maturation but, for the most part, maturation and spawning were simply monitored, along with survival.