The Biology and Culture of Tilapias

Control of Tilapia Reproduction

College of Inland Fisheries

Central Luzon State University

Muaoz, Nueva Ecva, Philippines

Present address :

Aquatic Biosystems

Bay, Lagum

Philippines

GUERRERO. R.D. 111. 1982. Control of tilapia reproduction, p. 309-316. In

R.S.V. Pullin and R.H. Lowe-McConnell (eds.) The biology and culture of

tilapias. ICLARM Conference Proceedings 7, 432 p. International Center

for Living Aquatic Resources Management, Manila, Philippines.

Uncontrolled reproduction gives excessive recruitment and low yields of

harvestablesize tilapias from culture ponds. Several effective methods have

been developed and applied for controlling this in commercial farms including

monosex culture, the use of predators and cage culture. Each method, how-

ever, has its advantages and disadvantages. Other methods that have been

tested are stock manipulation, the use of irradiation and chemosterilants,

reproduction inhibitors such as methallibure, salinity, light and temperature.

Further research is needed to determine the practicality of these methods for

commercial culture.

Introduction

Tilapias are an important foodfish in many tropical and subtropical
countries. More than 20 species of tilapia have been cultured in develop-
ing countries where animal protein is lacking. Tilapias are considered suitable
for culture because of their high tolerance to adverse environmental con-
ditions, their relatively fast growth and the ease with which they can be
bred.
The main drawback to the worldwide culture of tilapias is their exces-
sive recruitment in ponds which results in low yields of harvestable-size
fish. Where the acceptable market size is 150 g or more, this becomes a
critical problem.
In general, tilapias have high breeding rates. Their fecundity ranges from a