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Breeding success of 5 Cory’s shearwater Calonectris diomedea sub-colonies of Lavezzu Island (Lavezzi Archipelago, Corsica) was checked annually for 25 consecutive years from 1979 to 2004. Between 1989 and 1994, 4 ship rat Rattus rattus controls were performed in several subcolonies. In November 2000, rats were eradicated from Lavezzu Island and its 16 peripheral islets (85 ha) using traps then toxic baits. We compare cost (number of person-hours required in the field) and benefit (Cory’s shearwater breeding success) of control and eradication. The average breeding success doubled when rats were controlled or eradicated (0.82) compared to the situation without rat management (0.45). Moreover, the average breeding success after eradication (0.86) was significantly (11%) higher than after rat controls (0.75). Furthermore, the great variation in breeding success recorded among sub-colonies both with and without rat control declined dramatically after eradication, suggesting that rats had a major impact on breeding success. The estimated effort needed to perform eradication and checking of the permanent bait-station system during the year following eradication was 1360 person-hours. In contrast, rat control was estimated to require 240 or 1440 person-hours per year when implemented by trained and untrained staff, respectively. Within 6 yr, eradication cost is lower than control cost performed by untrained staff and confers several ecological advantages on more ecosystem components than Cory’s shearwater alone. Improved eradication tools such as hand or aerial broadcasting of toxic baits instead of the fairly labour-intensive eradication strategy we used would dramatically increase the economic advantage of eradication vs. control. Therefore, when feasible, we recommend eradication rather than control of non-native rat populations. Nevertheless, control remains a useful management tool when eradication is not practicable.

Status of coral reefs in the Polynesia Mana node is predominantly healthy. There are 6733 km2 of reefs scattered over 347 islands. Most (90%) are healthy, 5% have been destroyed or are at a critical stage and 5% are under threat;Reefs have been degraded around populated areas of Rarotonga (Cook Islands), Tahiti and Moorea (French Polynesia) and South Tarawa (Kiribati);Coral reefs support the livelihoods of Polynesian populations through subsistence fishing in all countries and through tourism and black pearl industries in French Polynesia and the Cook Islands; The main threats to the reefs are global warming for the remote reefs and land- based pollution for reefs near urban areas. Dynamite fishing still occurs in Wallis and Futuna;Reefs are mostly healthy in Wallis and Futuna, Tuamotu-Gambier and the Marquesas Archipelagos of French Polynesia; Reefs have largely recovered from past bleaching events in Phoenix Islands and Tarawa in Kiribati, and reefs are recovering from crown-of-thorns starfish (COTS) outbreaks in Rarotonga (Cook Islands) and from a cyclone in Niue; Reefs are facing a major COTS outbreak in the Society Archipelago of French Polynesia; and Socioeconomic assessments are now being implemented in the region, in parallel with ecological monitoring, to support coral reef management.