The degradation of pond bottom with time is usually forwarded by shrimp farm managers in New Caledonia to explain a decrease in production, associated or not with a pathology. To evaluate this possiblity, a study was carried out in 1996 on the pond bottom of 12 earthen ponds aged 2 to 21 crops, and managed in a semi-intensvie way or intensive way. Samples were collected to assess the silting up in the ponds, measure the organic matter accumulation in the sediment and estimate the chemical and physico-chemical quality of the sediment.