Contrast in the importance of arrow squid as prey of male New Zealand sea lions and New Zealand fur seals at The Snares, subantarctic New Zealand

Lalas, Chris; Webster, Trudi

doi:10.1007/s00227-013-2366-6

Cited by 13 publications

(3 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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. obs.).…”

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

“…As a conse-quence, opportunistic foragers may increase the consumption of benthic prey as they grow (Drago et al 2009a, Weise et al 2010, although such ontogenetic dietary change does not always occur and some species forage epipelagically throughout their life (Orr et al 2011). Most fur seals in the genus Arctocephalus indeed are pelagic foragers (Majluf 1989, Acuña & Francis 1995, Reid et al 2006, Aurioles-Gamboa & Camacho-Ríos 2007, Franco-Trecu et al 2012, Páez Rosas et al 2012, Makhado et al 2013, Franco-Trecu et al 2014, Lalas & Webster 2014, probably because their small body size limits oxygen stores and hence reduces time underwater and the chance of captur-ing demersal prey (Gentry et al 1986, Kooyman 1989, Costa 1991, Costa et al 2004. The exceptions are the 2 fur seal subspecies with the largest body size within the genus: A. pusillus pusillus and A. p. doriferus (Arnould 2008), which exploit prey mainly associated with the bottom (Stewardson 2001, Page et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic dietary changes in male South American fur seals Arctocephalus australis in Patagonia

Vales¹,

Cardona²,

García³

et al. 2015

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

This study assessed ontogenetic dietary changes in male South American fur seals Arctocephalus australis in northern and central Patagonia (Argentina) using stable isotope ratios (δ 15 N and δ 13 C) in vibrissae and bones. Sucking pups were characterised by higher δ 15 N values and lower δ 13 C values than older specimens. Weaning was associated with a marked drop of δ 15 N values, both in bone and vibrissae. Such a drop was inconsistent with the consumption of local prey and may reveal movement to distant foraging grounds or physiological changes associated with either fasting or rapid growth. Stable isotope ratios indicated that juveniles fed more pelagically than subadults and adults, but that there were no major differences between the 2 latter age categories. As subadults and adults are rather similar in body mass and are much larger than juveniles, body mass may play a role in the ontogenetic dietary changes reported. Nevertheless, demersal benthic prey were always scarce in the diet of male fur seals, which relied primarily on Argentine shortfin squid and small pelagic fish throughout life, though adults also consumed large amounts of decapod crustaceans available at shallow depths. Vibrissae did not reveal regular oscillations of δ 15 N or δ 13 C, except in 1 individual. Thus, male fur seals from northern and central Patagonia do not appear to migrate regularly between isotopically distinct areas, although nomadic displacements cannot be ruled out. KEY WORDS: Foraging ecology • Pinniped • Arctocephalus australis • Ontogenetic dietary change • Stable isotope analysis • δ 15 N • δ 13 C • Patagonia Resale or republication not permitted without written consent of the publisher This authors' personal copy may not be publicly or systematically copied or distributed, or posted on the Open Web, except with written permission of the copyright holder(s). It may be distributed to interested individuals on request.

show abstract

“…Many deep-sea pelagic organisms undergo diel vertical migrations, playing an important role in the flux of organic carbon between the surface and bathypelagic depths, including the water column and benthic ecosystems (Steinberg et al, 2008;Davison et al, 2013;Hudson et al, 2014;Irigoien et al, 2014;Steinberg and Landry, 2017;Taucher et al, 2018). Deep-sea cephalopod species are of particular interest due to their role in the diets of large fishes and marine mammals (Davis et al, 2007;Young et al, 2010;Romeo et al, 2012;Logan et al, 2013;Lalas and Webster, 2014;Salman and Karakulak, 2019;Southall et al, 2019). They are also voracious predators (Stewart et al, 2014;Corrales et al, 2015;Hoving and Robison, 2017) and are therefore potential vectors for contaminants through the water column (Unger et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Temporal Variability of Polycyclic Aromatic Hydrocarbons in Deep-Sea Cephalopods of the Northern Gulf of Mexico

2020

View full text Add to dashboard Cite

Contrast in the importance of arrow squid as prey of male New Zealand sea lions and New Zealand fur seals at The Snares, subantarctic New Zealand

Cited by 13 publications

References 49 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

Ontogenetic dietary changes in male South American fur seals Arctocephalus australis in Patagonia

Temporal Variability of Polycyclic Aromatic Hydrocarbons in Deep-Sea Cephalopods of the Northern Gulf of Mexico

Contact Info

Product

Resources

About