3. Results
3.1. Zootechnical results and mortality in ponds
After 249 and 209 days of rearing, final shrimp survivals and yields were 42% and 2.6 t ha− 1 and 23% and 1.3 t ha− 1 in ponds C and D, respectively. Feed conversion ratio (FCR) commonly expressed as the ratio of feed mass input to body mass output were 2.5 in ponds C and 3.4 in pond D. First mortalities were observed in both ponds between d63 and d69 when average individual shrimp weight was about 5 g. These mortalities were linked to Vp presence. Two main chronicle mortality periods were observed thereafter: the first in pond C occurred between d105 and d165 and the second in pond D between d133 and d154. In pond D, Vn and Vp were identified at d141 in 86% and 14% of the moribund shrimp, respectively. Due to a low number of moribund shrimp, pathogen identification was not possible in pond C.