A Northward Spread In The Breeding Distribution Of The New Zealand Sea Lion (Phocartos Hooeri)

Mcconkey, SD; McConnell, H. M.; Lalas, Chris; Heinrich, Sonja K.; Ludmerer, A; McNally, Nathan; Parker, E. Davis; Borofsky, C; Schimanski, Kate B.; McINTOSH, Gillian

doi:10.1071/am02097

Cited by 38 publications

(29 citation statements)

References 16 publications

(16 reference statements)

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“…Elsewhere, NZ sea lions are known to pup at 3 yr (McConkey et al 2002). Twenty percent of females that live to age 3, and could therefore be mated to give birth at Age 4, are never expected to breed and of those that do, 22% are never expected to have a pup survive.…”

Section: Nz Sea Lion Biologymentioning

confidence: 99%

New Zealand sea lions Phocarctos hookeri and squid trawl fisheries: bycatch problems and management options

Chilvers¹

2008

Endang. Species Res.

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The New Zealand (NZ) sea lion Phocarctos hookeri is one of the world's most rare and highly localized pinnipeds. NZ sea lions only breed on New Zealand's subantarctic islands, with 86% of breeding occurring on the Auckland Islands (50°S, 166°E). In 1995, the sea surrounding the Auckland Islands out to 12 nautical miles (n miles) was declared a Marine Mammal Sanctuary, primarily to protect the breeding area of this species. Subsequently, in 2003, this area became a concurrent notake Marine Reserve. Both protection measures ban commercial trawl fishing within this area. Trawling is the predominant anthropogenic impact upon this species, both through direct (mortality as a result of bycatch) and potential indirect (resource competition) effects. However, despite this areabased protection and the fisheries management measures in the surrounding waters, the species, which numbers less than 12 000 ind., has shown a 30% decline in pup production over the last 8 yr. In this paper, I review the biology, foraging ecology and management of NZ sea lions in relation to the subantarctic arrow squid Nototodarus sloanii fishery to explore alternative management options within the framework of current legalisation in New Zealand. Management options need to afford better protection for this declining species, while still allowing profitable commercial fisheries operations for arrow squid in New Zealand waters.

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Section: Nz Sea Lion Biologymentioning

confidence: 99%

New Zealand sea lions Phocarctos hookeri and squid trawl fisheries: bycatch problems and management options

Chilvers¹

2008

Endang. Species Res.

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“…Since 1994, the first and currently only recolonising population of breeding female New Zealand sea lions on the New Zealand mainland has established itself on the Otago Peninsula (McConkey et al 2002). This population was started by a single matriarch, which was born in the Auckland Islands but did not show the typical philopatry of females of this species (Chilvers & Wilkinson 2008) and moved to Otago to breed.…”

Section: Introductionmentioning

confidence: 99%

Foraging behaviour indicates marginal marine habitat for New Zealand sea lions: remnant versus recolonising populations

Augé¹,

Chilvers²,

Moore³

et al. 2011

Mar. Ecol. Prog. Ser.

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The New Zealand sea lion Phocarctos hookeri historically bred on the New Zealand mainland (South and North Islands). Subsistence hunting and later commercial sealing reduced its distribution to 3 breeding areas at the spatial edges of its historical distribution range, in the Auckland Islands (AI) and on Campbell Island. Here, we present foraging areas and foraging trips of female New Zealand sea lions from the Otago Peninsula, where a recolonising population has been found in the core of the historical range of the species. We compare the results with data from the AI in order to assess the theory that the spatial margin of a species' distribution represents the lower end of habitat suitability. Female New Zealand sea lions at Otago had significantly smaller foraging ranges than females at the AI (mean 65% Kernel ranges: 47 ± 25 km 2 versus 687 ± 109 km 2 ), made shorter foraging trips (mean 11.8 ± 2.3 h versus 66.2 ± 4.2 h), and spent 40% less time at sea overall. Juvenile females at Otago from age 2 onwards could access foraging grounds used by adult females nursing pups; this is unlikely to be the case at the AI due to the large distances and associated depths of foraging grounds. Our study illustrates the theory that spatial marginality is related to habitat marginality. Existing management measures to mitigate the impact of bycatch in fisheries on declining remnant colonies around the AI were modelled based on populations exploiting optimal habitat. They should now integrate this new information.

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“…Two such mainland re-colonisations have occurred for New Zealand sea lions, one at Otago Peninsula, South Island, New Zealand in (McConkey et al 2002 and one at Stewart Island/Rakiura, the most southern of New Zealand's three main islands, recognised since 2011 (Chilvers & Meyner 2017;Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Preliminary assessment of the foraging behaviour and population dynamics of a cryptic population of the endangered New Zealand sea lion

Chilvers¹

2018

NZ J Ecol

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Abstract:The endangered New Zealand sea lion (Phocarctos hookeri) has recently been confirmed as breeding on Stewart Island/Rakiura, southern New Zealand. This area is thought to have the largest number of sea lion pups born outside of the New Zealand subantarctics. However, the sparse distribution and cryptic behaviour of this population means known human threats and their effects on the population will be difficult to determine, limiting conservation priority setting and management. This research aimed to investigate the foraging behaviour of adult females from the population and examine what information is available to help determine current population parameters including undertaking pup surveys in the area. Foraging behaviour research was undertaken in the Austral autumn 2012 and 2013, while pup production surveys were undertaken in March each year between 2011 and 2016. Pup production surveys show up to 36 pups are born in the Stewart Island area annually. The foraging behaviour of 14 adult female New Zealand sea lions was characterised by short foraging trips (c. 12 hrs), close to shore or in areas of known upwellings, undertaking short, shallow dives (average 2.5 mins, 60 m). This diving behaviour is intermediate between the foraging behaviours of females from Enderby Island (Auckland Islands), the largest but severely declining population of New Zealand sea lions, and Otago (mainland New Zealand), a smaller, increasing recolonising population. Based on the foraging behaviour and limited population dynamic information collected from the Stewart Island population, it is likely the Stewart Island population has survival and reproductive parameters more like the recolonising Otago population than the declining Auckland Islands population. Such information is critical for determining the impacts of the known direct and indirect human impacts on this small isolated population, which is likely to be important for the survival of the endangered New Zealand sea lion species as a whole.

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A Northward Spread In The Breeding Distribution Of The New Zealand Sea Lion (Phocartos Hooeri)

Cited by 38 publications

References 16 publications

New Zealand sea lions Phocarctos hookeri and squid trawl fisheries: bycatch problems and management options

New Zealand sea lions Phocarctos hookeri and squid trawl fisheries: bycatch problems and management options

Foraging behaviour indicates marginal marine habitat for New Zealand sea lions: remnant versus recolonising populations

Preliminary assessment of the foraging behaviour and population dynamics of a cryptic population of the endangered New Zealand sea lion

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