Recruitment control and production of Tilapia aurea (Steindachner) with the predator, Cichlasoma managuense (Günther)

The effects of different stocking rates and ratios of Tilapia aurea (Steindachner) in combination with Cichlasoma managuense (Gunther) on tilapia recruitment and production were evaluated in 440 m 2 ponds. The research was conducted at the National Fisheries Station in El Salvador, Central America. The tilapia A T value, the total weight of marketable tilapia (14 cm or larger) expressed as a percentage of the total weight of the whole tilapia population, averaged 96 or greater at a stocking ratio of 4:1 (fingerling tilapia: fingerling C. managuense ) and at a stocking ratio of 8:1 (fingerling tilapia: adult C. managuense ). Tilapia A T values at a stocking ratio of 8:1 (fingerling tilapia: fingerling C. managuense ) ranged from 71–89. Highest estimated annual production of marketable tilapia (3611 kg ha −1 ) occurred at the highest stocking rate of 12000 tilapia ha −1 in populations with an average tilapia A T value of 98. Greatest weight gain of marketable tilapia (167 g of 1.17 g day −1 ) occurred at the lowest stocking rate of 6000 tilapia ha −1 in populations with an average tilapia A T value of 99. Estimated annual production of marketable C. managuense ranged from 212–414 kg ha −1 . The average weight gain of marketable fish varied from 48–60 g (0.32–0.40 g day −1 ). The average C. managuense , A T value was 54, ranging from 29–84. The estimated production of marketable fish of both species at stocking rates of 6000, 9000 and 12000 tilapia ha −1 in populations with tilapia A T values of 96 or greater averaged 3295, 3290 and 4025 kg ha −1 per year, respectively.