Distribution, pup production and mortality of New Zealand sea lion on Campbell Island 2007/08
Introduction
This paper describes the distribution, pup production and mortality of the New Zealand sea lion on Campbell Island in 2007/08. The work was completed through Crown funding provided by Marine Conservation Services. Published 2009.Download the publication
The paper can currently be downloaded from NZ Journal of Ecology
Summary
Surveys were undertaken at Campbell Island/Motu Ihupuku during January and February 2008, to determine the distribution and pup production of New Zealand sea lions (NZ sea lion; Phocarctos hookeri).
In addition, necropsies were performed at the main breeding site of Davis Point to determine the principal causes of early mortality for NZ sea lion pups. In total, 397 pups were tagged and 186 untagged pups were found dead, giving a minimum pup production of 583 pups and a one month of age mortality estimate of 40%.
This represents a higher pup production than previous estimates from Campbell Island (although survey techniques are not comparable), and equates to 21% of the total pup production for NZ sea lions in the 2007/08 season. Early pup mortality was high (40%) at Campbell Island, with trauma, starvation, and drowning in rock pools and peat mires the major causes of death.
Pups were concentrated in two colonial breeding sites: Davis Point on the north shore of Perseverance Harbour (76%) and a newly recorded breeding site (Paradise Point) on the southern shore of Perseverance Harbour (21%). Non-colonial breeding or single pups occurred around the southern parts of the island from sea level to 400 m; however, these only contributed 3% of the known pup production.