The New Zealand fur seal (Arctocephalus forsteri) did not breed in Otago, southeastern South Island, New Zealand from the 17th Century until the late 1970's. Here we report a recent dramatic increase in pup production for Otago Peninsula, from 20–30 pups born in two rookeries in 1982/83 to a minimum (from a direct count) of 673 born at eleven distinct rookeries during the 1993/94 breeding season. Adjustments for precensus mortality and for undercounting were calculated from one site and applied to all rookeries. These adjustments raised the 1993/94 production figure to an estimated 1136 ± 98 pups. The implications of these adjustments, and of making pup counts based on surveys, are discussed. Future monitoring of pup numbers should be carefully timed to coincide with the end of the local pupping season.