Size and experience matter: diving behaviour of juvenile New Zealand sea lions (Phocarctos hookeri)

Leung, Elaine S.; Chilvers, B. Louise; Nakagawa, Shinichi; Robertson, Bruce C.

doi:10.1007/s00300-013-1405-6

Cited by 17 publications

(12 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…obs.). These groups likely have some foraging area overlap with females, particularly juvenile males (as seen at Enderby Island; Leung et al 2012Leung et al , 2014. In addition, there are large numbers of other marine carnivores which forage in these areas, including New Zealand fur seals Arctocephalus fosteri (>20 000 individuals; Lalas 2008) that could have an overlap or be competing for prey (Lalas & Webster 2014) whereas fur seal numbers are limited at the Auckland Islands (pers.…”

Section: Discussionmentioning

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

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

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

View full text Add to dashboard Cite

show abstract

“…The oxygen storage capacity of an air-breathing marine predator can be closely related to body size, as the larger the individual, the more tissue (blood, muscle and lungs) available to store larger volumes of oxygen (Burns, 1999;Costa et al, 2004;Hassrick et al, 2013;Weise and Costa, 2007). Studies reporting positive relationships of oxygen storage capacity and body mass have typically approached ontogenetic physiological changes, as they have compared smaller, under-developed individuals such as pups and small juveniles with adult individuals (Burns, 1999;Burns et al, 2005;Fowler et al, 2007;Leung et al, 2014;Richmond et al, 2006;Weise and Costa, 2007). As hypothesized, larger South American sea lions had larger total body oxygen stores (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…(Burns, 1999;Hassrick et al, 2013;Meir et al, 2013;Ponganis et al, 2011;Yamamoto et al, 2011)], or on the diving behavior of specific species with restricted distributions [e.g. Australian sea lion, Neophoca cinerea (Fowler et al, 2007); New Zealand sea lion, Phocarctos hookeri (Costa et al, 1998;Leung et al, 2014); Galapagos sea lion, Zalophus wollabaecki (Villegas-Amtmann and ].…”

Section: Introductionmentioning

confidence: 99%

Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lionOtaria byronia

Hückstädt

Tift

Riet-Sapriza

et al. 2016

Journal of Experimental Biology

View full text Add to dashboard Cite

Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Because of their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral and physiological plasticity of a marine predator in different environments. We measured the oxygen stores and diving behavior of South American sea lions throughout most of its range, allowing us to demonstrate that diving ability and behavior vary across its range. We found no significant differences in mass-specific blood volumes of sea lions among field sites and a negative relationship between massspecific oxygen storage and size, which suggests that exposure to different habitats and geographical locations better explains oxygen storage capacities and diving capability in South American sea lions than body size alone. The largest animals in our study (individuals from Uruguay) were the shallowest and shortest duration divers, and had the lowest mass-specific total body oxygen stores, while the deepest and longest duration divers (individuals from southern Chile) had significantly larger mass-specific oxygen stores, despite being much smaller animals. Our study suggests that the physiology of airbreathing diving predators is not fixed, but that it can be adjusted, to a certain extent, depending on the ecological setting and or habitat. These adjustments can be thought of as a 'training effect': as the animal continues to push its physiological capacity through greater hypoxic exposure, its breath-holding capacity increases.

show abstract

“…, ; Leung et al . ). These limitations may restrict the amount of foraging habitat available to juveniles, and may contribute to decreased foraging success and high mortality during periods of reduced prey availability, such as El Niño events (Trillmich and Limberger , Trillmich et al .…”

Section: Animal and Tag Summary Of Satellite‐tracked Juvenile Califormentioning

confidence: 97%

Movements and dive behavior of juvenile California sea lions from Año Nuevo Island

McHuron

Block

Costa

2017

Marine Mammal Science

View full text Add to dashboard Cite

Size and experience matter: diving behaviour of juvenile New Zealand sea lions (Phocarctos hookeri)

Cited by 17 publications

References 44 publications

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

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

Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lionOtaria byronia

Movements and dive behavior of juvenile California sea lions from Año Nuevo Island

Contact Info

Product

Resources

About