A Linear Growth Model for Nile Tilapia in Intensive Aquaculture

Abstract

Efficient intensive aquaculture requires a growth model that accurately predicts daily growth in length increments as a function of temperature. Using fish of different sizes but from the same source, I grew androgen-sex-reversed Nile tilapia Oreochromis niloticus over a range of temperatures in two different years. In 2002, fish grew from 1.8 g (47 mm) to a range of 5–26 g (67–112 mm) in 50 d at 21–30°C temperatures. Fish growth (mm/d) was highly correlated with temperature (r = 0.99). The experiment was repeated with larger fish in 2005, during which 47-g (137-mm) fish grew to 107–219 g (178–225 mm) in 70 d. The coefficient of correlation for growth versus temperature was 0.94. The two slopes did not differ (P < 0.05), so I present the following equation to predict Nile tilapia growth rates in flowing-water culture for the temperature range of 21–30°C: ΔL = −1.6707 + 0.09682T (r ² = 0.95), where ΔL is predicted growth (mm/d) and T is temperature (°C). Weight (W; g) can be converted to length (L; mm) for male Nile tilapia with the expression W = 1,861 × 10⁻⁸ · L ³.