Almost 3,000 sturgeons have been tagged since 1984, and incidental captures of sturgeons tagged (N ¼ 154) and untagged (N ¼ 86) have been reported by marine fishermen. We suspected that these data did not reflect the total captures at sea. Therefore, we carried out a large survey which provided information about captures that were not previously declared. The high fishing pressure on sturgeon by incidental captures and poaching at sea was demonstrated. It confirmed that several hundreds of sturgeons were captured in near the Gironde estuary in 1997–1998. The stock assessment made on juvenile in estuary and the absence of breeders returning to their spawning sites lead us to think that most probably capture at sea was the first cause of mortality for these cohorts. While the stocking is in progress, the communication effort must continue, and effective enforcement is urgently required to eliminate poaching.