Pilot project to test biodegradable ropes at FADs in real fishing conditions in western Indian ocean

The present study summarizes the results of a pilot project to test biodegradable ropes at FADs in real fishing conditions. One of the difficulties when testing experimental FADs in purse seine fishery is that fishers fish on any FAD found at sea, so that FADs change hands very often making difficult to revisit experimental FADs to collect data and get significant results. The main objective of the pilot was learning from this experience to develop a large-scale deployment of biodegradable FADs at sea, by detecting potential difficulties and issues related mainly to effective data gathering on FADs under test. In order to compare the performance of biodegradable and non-biodegradable FADs, International Seafood Sustainability Foundation (ISSF) deployed in collaboration with 6 purse seiners from INPESCA fleet in Western Indian Ocean, a total of 174 FADs, 89 non-biodegradable and 85 biodegradable. Two different FAD designs were tested working at different depths (10m, 30m, 50m and 70 m). A total of 74.913 biomass samples were collected using echo-sounder buoys attached to those FADs. Our results show similar aggregative patterns of fish (tuna and non-tuna species) for non-biodegradable and biodegradable FADs. Life-time of FADs and implications of our results for future experiments are discussed.