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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.

A supplementary feed containing 30% coffee pulp was evaluated for use in the culture of Tilapia aurea in El Salvador, Central America. A comparison of the coffee pulp feed with a feed containing all of the same ingredients except coffee pulp was made with T. aurea raised in 1.0-m 3 cages suspended in a fertilized earthen pond. Survival was high in all treatments and there was no significant difference in average weight gain between groups of fish receiving the two experimental feeds. Production trials were conducted in 100-m 2 fish pens and in 0.05-ha earthen ponds. Pen-raised fish receiving coffee pulp feed grew faster throughout the experiment, and total production was approximately twice that in control treatments. Highest production in pens was 1.25 kg/m 2 per year. Results of production pond trials using T. aurea at 9 000/ha and stocked with the piscivorous Cichlasoma managuense yielded an estimated 3 392 kg/ha per year in fed treatments and 2 049 kg/ha per year in controls. Low feed conversion (1.92) and low feed cost resulted in an increase in net annual earnings of $251.00/ha.