Effects of white shrimp (Litopenaeus vannamei) and tilapia nilotica (Oreochromis niloticus var. Spring) in monoculture and co-culture systems on water quality variables and production in brackish low-salinity water earthen ponds during rainy and dry seasons

Aim of study: To determine the effects of white shrimp (Litopenaeus vannamei) and tilapia nilotica (Oreochromis niloticus var. Spring) in monoculture and co-culture on water quality variables and production in earthen ponds during dry and rainy seasons.Area of study: A shrimp farm (total area 20 ha) at Chiripa, San Blas Nayarit, Northwest coast of Mexico (21° 37' 34.53 " N; 105° 18' 16.31" W).Material and methods: Two production cycles were performed in a completely randomized design consisting of two treatments and three replications each during rainy season (September-December) and dry season (February-May). Shrimp was the main crop and tilapia the secondary species.Main results: White shrimp (10 org/m2) can be co-cultured with Nile tilapia at a stocking high density (4 org/m2), leading to improved water quality and better utilization of nutrients in dry season than in rainy season. However, the shrimp’ highest weight was recorded in the tilapia-shrimp co-culture ponds during rainy season due to higher water temperature and better quality of live food. The mean individual weight, biomass and survival of the shrimp, in co-culture ponds were greater than those of the shrimp monoculture, in the two seasons studied.Research highlights: There was a trend towards greater concentration of nutrients in the water of the monoculture ponds and, lower dissolved oxygen and higher BOD5 in co-culture ponds in the dry season than in the rainy season