Colony growth and pup condition of the New Zealand fur seal (Arctocephalus forsteri) on the Kaikoura coastline compared with other east coast colonies

Abstract

Abstract.Since its near extermination by sealing, the New Zealand fur seal (Arctocephalus forsteri) has been recolonising areas of its former range throughout New Zealand and Australia. This study examined fur seal population growth over four breeding seasons spanning 2002–05 at the Ohau Point and Lynch’s Reef colonies in Kaikoura and the Horseshoe Bay and Te Oka Bay colonies on Banks Peninsula, on the east coast of New Zealand. Estimates of pup numbers were made using mark–recapture techniques and condition indices were used to assess the body condition of pups in each colony. We found that the Ohau Point and Te Oka Bay colonies are growing exponentially (32% and 47% per annum respectively), reaching nearly 600 pups at Ohau Point and 300 pups at Te Oka Bay, whereas Horseshoe Bay appears stable. Pups born at Ohau Point are consistently heavier and in better condition than their Banks Peninsula counterparts despite the faster rate of growth observed at Te Oka Bay. An El Niño event in 2003 coincided with a drop in mass and condition at the Banks Peninsula colonies, but not at the Kaikoura colony. This discrepancy between colonies in response to environmental conditions suggests that colony-specific variables at Kaikoura may provide more favourable conditions for rearing pups than on Banks Peninsula.

An assessment of thermal-image acquisition with an unmanned aerial vehicle (UAV) for direct counts of coastal marine mammals ashore

“…Zealand fur seal are both excellent species on which to focus research, due to their biological similarities and different risk levels (Boren et al 2006;Robertson and Chilvers 2011). D r a f t …”

Diverse foraging strategies by a marine top predator: Sperm whales exploit pelagic and demersal habitats in the Kaikōura submarine canyon

“…It harbours exceptional biomass of infaunal and epifaunal invertebrates, including nematodes, and also benthic-feeding fish Leduc et al 2012). Furthermore, the presence of many top-predators targeting mesopelagic prey (e.g., Benoit-Bird et al 2004, Boren et al 2006 suggests that the area hosts a highly productive pelagic system. The Kaikōura Canyon is also an important year-round foraging ground for male sperm whales (Physeter macrocephalus) (Childerhouse et al 1995, Jaquet et al 2000, deep-diving predators (Papastavrou et al 1989, Watkins et al 1993) that use echolocation to detect and locate prey (Møhl et al 2000, Madsen et al 2002.…”

Motor vehicle collisions and the New Zealand fur seal in the Kaikoura region

“…1). Pup production is increasing, with pup numbers at the largest site, Ohau Point, reaching 600 in 2005 (Boren et al . 2006).…”

“…Twenty‐five percent of all individuals on the road and 61% (30/49) of all fatalities were pups. However, annually these values have increased since 2000 in parallel with the recolonization and rapid expansion of the Ohau Point colony (Boren et al 2006). In 2005, 65% (13/20) of seals on the road and 83% (10/12) of fatalities were pups.…”

“…In 2005, 65% (13/20) of seals on the road and 83% (10/12) of fatalities were pups. The number of pups killed annually in road incidents since 1996 represented on average 2.4 ± 1.4% (range: 0.5–3.2%) of the number of pups born each year, estimated from mark–recapture data obtained over this time period (Boren et al 2006).…”