Estimating regional population size and annual harvest intensity of the sooty shearwater in New Zealand

Abstract

Recent comprehensive survey data from multiple New Zealand offshore islands were combined with demographic population models to produce the first formal estimate of the total population of sooty shearwaters within New Zealand territory. We estimated the total population over 1994-2005 to be 21.3 (19.0-23.6) million individual birds in the New Zealand region. This population consisted of 12.8 (12.0-13.6) million adults, 2.8 (2.5-3.1) million chicks, and 4.4 (4.2-4.7) million breeding pairs. Breeding sooty shearwaters were concentrated primarily around the southern islands of New Zealand, with 53% breeding in the Titi Islands surrounding Rakiura (Stewart Island). Rakiura Maori muttonbirders were estimated to harvest 360 000 (320 000-400 000) sooty shearwaters per year, equivalent to 18% of the chicks produced in the harvested areas and 13% of chicks in the New Zealand region. Overall, 11% of the chicks within the Tītī Islands live on unharvested ground. Systematic and widespread surveys of breeding colonies in South America are needed before a reliable global sooty shearwater population estimate can be calculated.

Stable isotope values delineate the non-breeding distributions of sooty shearwaters Puffinus griseus in the North Pacific Ocean

“…In New Zealand, censuses in 1994−2004 suggest an estimated total breeding population of 4.2−4.7 million pairs, with an overall population of approximately 20 million individuals (Newman et al 2009). However, over recent decades, there is growing evidence to indicate marked declines in sooty shearwater populations (Veit et al 1996, 1997, Scofield & Christie 2002, and the conservation status of sooty shearwater in New Zealand is defined as 'at risk -declining' (Robertson et al 2013).…”

Interdisciplinary progress in approaches to address social-ecological and ecocultural systems

“…They nest in southern New Zealand, but also in Australian Tasmania, New South Wales and Victoria. The population of these petrels is estimated to be some 20 million birds (Newman et al 2009). However, evidence seemed to indicate a long-term decline in tītī.…”

“…However, evidence seemed to indicate a long-term decline in tītī. Henrik Moller of the University of Otago began working with Māori on Rakiura from the mid-1990s (Newman et al 2009;Stephensen & Moller 2009). The combination of scientific methods and knowledge with māturanga (traditional knowledge) has led to new insights, including one on climate change.…”

Breeding parameters of the Sooty Shearwater (Ardenna grisea) on Long Island, New Zealand

“…Of the total New Zealand population, 98% breeds on the satellite islands of Stewart Island and on islands of the Snares Group (Newman et al 2009a), with the rest in a few mainland sites and on scattered islands along the New Zealand coast as far north as the Three Kings Islands . Breeding populations of Sooty Shearwaters are also found on islands off south-eastern Australia (Lane and White 1983) and Chile (Marin 1984).…”

“…The Sooty Shearwater (Ardenna grisea), also commonly known in New Zealand as the tıtı or muttonbird, is an abundant seabird in New Zealand, with a population of >21 million individuals (Newman et al 2009a). Of the total New Zealand population, 98% breeds on the satellite islands of Stewart Island and on islands of the Snares Group (Newman et al 2009a), with the rest in a few mainland sites and on scattered islands along the New Zealand coast as far north as the Three Kings Islands .…”