Early diving behaviour in juvenile penguins: improvement or selection processes

Orgeret, Florian; Weimerskirch, Henri; Bost, Charles‐André

doi:10.1098/rsbl.2016.0490

Cited by 38 publications

(63 citation statements)

References 12 publications

(25 reference statements)

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“…Orgeret et al (2016) showed that juvenile king penguins from the same colony move over considerable distances during their first year at sea, with probable changes in T w . In our calculations concerning heat loss, we assumed a T w of 4°C (Guinet et al, 1997;Charrassin and Bost, 2001), while birds might have foraged in somewhat colder water.…”

Section: Concurrent Changes In Dive Effort And/or Changes In T Wmentioning

confidence: 99%

“…While juvenile birds remained at sea for their entire first year (apart from brief periods spent on land or ice), adult breeders repeatedly switched between foraging at sea and fasting in the colony, changing the overall dynamics of their body condition/insulation and, consequently, peripheral temperatures at sea. Orgeret et al (2016), who deployed satellite tags on 17 juvenile king penguins from the same Crozet colony during their first year at sea, found that dive performance (dive depth and duration) in 5 of these birds started to decline significantly after ∼3 months and satellite transmission stopped after ∼4 months, when these birds presumably died. The authors attributed this outcome to the inability of these birds to increase their dive capacity (as surviving birds did) when conditions became difficult, resulting in early mortality due to starvation (Orgeret et al, 2016).…”

Section: Seasonal Changes In Body Condition and Insulation Statusmentioning

confidence: 99%

“…Orgeret et al (2016), who deployed satellite tags on 17 juvenile king penguins from the same Crozet colony during their first year at sea, found that dive performance (dive depth and duration) in 5 of these birds started to decline significantly after ∼3 months and satellite transmission stopped after ∼4 months, when these birds presumably died. The authors attributed this outcome to the inability of these birds to increase their dive capacity (as surviving birds did) when conditions became difficult, resulting in early mortality due to starvation (Orgeret et al, 2016). This supports our hypothesis of an energetic challenge in these juvenile king penguins during their first months at sea.…”

Section: Seasonal Changes In Body Condition and Insulation Statusmentioning

confidence: 99%

“…Juvenile king penguins leave the colony for the first time when ∼1 year old and disperse at sea for an extended period (1-3 years), interrupted only by an annual moult on land, after which most birds return to their natal colony and attempt to recruit into the breeding population (Weimerskirch et al, 1992;Saraux et al, 2011). This initial dispersal phase at sea is probably a critical phase in their life (Orgeret et al, 2016), when mortality is high compared with that of adults (Le Bohec et al, 2007;Saraux et al, 2011), and foraging proficiency might play a key role in their survival (Wunderle, 1991;Daunt et al, 2007). Apart from finding favourable foraging sites, birds have to develop effective prey search patterns as well as physiological capacities (breath holding, locomotion, thermoregulation) that enable them to capture sufficient prey (predominately myctophid fishes; Cherel and Ridoux, 1992;Raclot et al, 1998;Bost et al, 2002), often at great depth (Charrassin and Bost, 2001), to meet their energetic needs.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from finding favourable foraging sites, birds have to develop effective prey search patterns as well as physiological capacities (breath holding, locomotion, thermoregulation) that enable them to capture sufficient prey (predominately myctophid fishes; Cherel and Ridoux, 1992;Raclot et al, 1998;Bost et al, 2002), often at great depth (Charrassin and Bost, 2001), to meet their energetic needs. However, studies investigating the ontogeny of foraging behaviour in marine birds in the wild are still rare (Daunt et al, 2007;Thiebot et al, 2013;Orgeret et al, 2016;De Grissac et al, 2016), with most studies focusing on dispersive movements (Clarke et al, 2003;Kooyman and Ponganis, 2008;Wienecke et al, 2010;Pütz et al, 2014), and studies concerning physiological aspects are lacking (Ponganis et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Apparent changes in body insulation of juvenile king penguins suggest an energetic challenge during their early life at sea

Enstipp

Bost

Bohec

et al. 2017

Journal of Experimental Biology

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Little is known about the early life at sea of marine top predators, like deep-diving king penguins (Aptenodytes patagonicus), although this dispersal phase is probably a critical phase in their life. Apart from finding favourable foraging sites, they have to develop effective prey search patterns as well as physiological capacities that enable them to capture sufficient prey to meet their energetic needs. To investigate the ontogeny of their thermoregulatory responses at sea, we implanted 30 juvenile king penguins and 8 adult breeders with a small data logger that recorded pressure and subcutaneous temperature continuously for up to 2.5 years. We found important changes in the development of peripheral temperature patterns of foraging juvenile king penguins throughout their first year at sea. Peripheral temperature during foraging bouts fell to increasingly lower levels during the first 6 months at sea, after which it stabilized. Most importantly, these changes re-occurred during their second year at sea, after birds had fasted for ∼4 weeks on land during their second moult. Furthermore, similar peripheral temperature patterns were also present in adult birds during foraging trips throughout their breeding cycle. We suggest that rather than being a simple consequence of concurrent changes in dive effort or an indication of a physiological maturation process, these seasonal temperature changes mainly reflect differences in thermal insulation. Heat loss estimates for juveniles at sea were initially high but declined to approximately half after ∼6 months at sea, suggesting that juvenile king penguins face a strong energetic challenge during their early oceanic existence.

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Section: Concurrent Changes In Dive Effort And/or Changes In T Wmentioning

confidence: 99%

Section: Seasonal Changes In Body Condition and Insulation Statusmentioning

confidence: 99%

Section: Seasonal Changes In Body Condition and Insulation Statusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Apparent changes in body insulation of juvenile king penguins suggest an energetic challenge during their early life at sea

Enstipp

Bost

Bohec

et al. 2017

Journal of Experimental Biology

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High mortality of adult female Magellanic penguins by gillnet fisheries in southern Brazil

Fogliarini

Bugoni

Haimovici

et al. 2019

Aquatic Conservation

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Bycatch in gillnet fisheries is one of the main threats to several penguin species. Magellanic penguins (Spheniscus magellanicus) are caught by gillnets during their wintering in southern Brazil. However, current information is based only on a small number of sets observed during a single fishing trip. This study assesses bycatch rates of bottom and drift gillnets operating in southern Brazil, and describes the sex and age classes of individuals captured. In 80 bottom gillnet sets, 33 penguins were captured (85% adults), 14 were sexed of which 13 were females. In 41 drift gillnet sets, four penguins were captured, three of which were juveniles. The mean bycatch rates, measured as number of penguins km−2 of net and number of penguins km−2 h−1, were significantly higher for the drift gillnets. Despite the lower bycatch rates, owing to the higher fishing effort in terms of number of boats, net length, net area, soak time and fishing season, the magnitude of penguin bycatch in the bottom gillnet fishery cannot be ignored. Despite based on small sample size, the predominance of adult and female Magellanic penguins as bycatch in gillnet fisheries in southern Brazil agrees with previous studies suggesting that females displace further north than males. In addition, such evidence contributes to the male‐biased sex ratio in breeding grounds, and the long‐term decline of major Patagonian colonies owing to higher female mortality during winter.

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Body condition influences ontogeny of foraging behavior in juvenile southern elephant seals

Orgeret

Cox

Weimerskirch

et al. 2018

Ecology and Evolution

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Ontogeny of diving and foraging behavior in marine top predators is poorly understood despite its importance in population recruitment. This lack of knowledge is partly due to the difficulties of monitoring juveniles in the wild, which is linked to high mortality early in life. Pinnipeds are good models for studying the development of foraging behaviors because juveniles are large enough to robustly carry tracking devices for many months. Moreover, parental assistance is absent after a juvenile departs for its first foraging trip, minimizing confounding effects of parental input on the development of foraging skills. In this study, we tracked 20 newly weaned juvenile southern elephant seals from Kerguelen Islands for up to 338 days during their first trip at sea following weaning. We used a new generation of satellite relay tags, which allow for the transmission of dive, accelerometer, and location data. We also monitored, at the same time, nine adult females from the colony during their post‐breeding trips, in order to compare diving and foraging behaviors. Juveniles showed a gradual improvement through time in their foraging skills. Like adults females, they remarkably adjusted their swimming effort according to temporal changes in buoyancy (i.e., a proxy of their body condition). They also did not appear to exceed their aerobic physiological diving limits, although dives were constrained by their smaller size compared to adults. Changes in buoyancy appeared to also influence their decision to either keep foraging or return to land, alongside the duration of their haul outs and choice of foraging habitat (oceanic vs. plateau). Further studies are thus needed to better understand how patterns in juveniles survival, and therefore elephant seal populations, might be affected by their changes in foraging skills and changes in their environmental conditions.

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Early diving behaviour in juvenile penguins: improvement or selection processes

Cited by 38 publications

References 12 publications

Apparent changes in body insulation of juvenile king penguins suggest an energetic challenge during their early life at sea

Apparent changes in body insulation of juvenile king penguins suggest an energetic challenge during their early life at sea

High mortality of adult female Magellanic penguins by gillnet fisheries in southern Brazil

Body condition influences ontogeny of foraging behavior in juvenile southern elephant seals

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