Three independent studies were conducted to quantify ultimate biochemical oxygen demand (UBOD) and the corresponding decomposition rate constant for production pond (average 21.5ha each) waters and effluents on six semi-intensively managed marine shrimp (Litopenaeus vannamei) farms in Honduras. Samples were collected during the rainy season in studies 1-3 and during the dry season only in Study 1. pond water samples were collected during the culture period and/or at harvest.The dry season 30-d biochemical oxygen demand of pond waters across all farms was 26% lower and UBOD was 54% lower, but the decomposition rate constant was more than twice as great as during the rainy season.