Ship rat Rattus rattus eradication on Nahkapw Island, Federated States of Micronesia, Pacific Ocean

  • Published source details Wegmann A., Braun J. & Neugarten R. (2008) Ship rat Rattus rattus eradication on Nahkapw Island, Federated States of Micronesia, Pacific Ocean. Conservation Evidence, 5, 18-22.


As part of a larger project attempting to reduce predation pressure from introduced rats Rattus spp. on native fauna and flora on several islands off Pohnpei main island (Pacific Ocean), a rat eradication program was undertaken on the small island of Nahkapw (1.58 ha). Prior to commencement of eradication, a pre-treatment rat population assessment was undertaken; only a single female ship rat R.rattus was caught (subsequently fitted with a radio-collar and released) and wax indicator success was also very low, suggesting that the island hosted a very low density of rats. Bait-stations were positioned on the ground along two transects that ran the length of the island spaced approximately 20 m apart; the distance between the two transects varied but was never less than 10 m or more than 30 m. After 2-weeks of inactivity, these stations were supplemented with 22 bait stations attached to tree trunks adjacent to each ground-based bait station. These tree bait stations were maintained until the radio-collared rat died (25 days after initial bait placement). There was no evidence of non-target species being adversely affected by the bait.

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