Mouthing off about fish capture: Jaw movement in pinnipeds reveals the real secrets of ingestion

Liebsch, Nikolai; Wilson, Rory P.; Bornemann, Horst; Adelung, D.; Plötz, Joachim

doi:10.1016/j.dsr2.2006.11.014

Cited by 61 publications

(49 citation statements)

References 24 publications

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“…2), with high frequencies of shallow dives to depths less than 50 m. Deep dives were concentrated around 100 m for seals AF4, JM5 and JF6. One adult male (AM2) and one adult female (AF3) displayed high numbers of deep dives to depths [200 m, while the remaining seal (AM1) concentrated its dives at depths between 100 and 150 m. The bimodal patterns of dive depths are similar to that reported for seals tagged at the Drescher Inlet (Plötz et al 2001), although seals there targeted deeper water layers close to the seafloor in the region of 400 m, where evidence for foraging (based on jaw movement data) was also reported by Liebsch et al (2007). Seals AM1, AF4, JM5 and JF6 displayed increased bottom times when diving to similar depths, compared to the depths they most often dived to (Fig.…”

Section: Divessupporting

confidence: 58%

Hydrographic influences on the summer dive behaviour of Weddell seals (Leptonychotes weddellii) in Atka Bay, Antarctica

et al. 2013

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In order to gain insights into species-level behavioural responses to the physical environment, it is necessary to obtain information from various populations and at all times of year. We analysed the influences of physical environmental parameters on the mid-summer dive behaviour of Weddell seals (Leptonychotes weddellii) from a little-known population at Atka Bay, Antarctica. Dive depth distributions followed a typical bimodal pattern also exhibited by seals from other populations and seals targeted both shallow water layers of \50 m and depths near the seafloor. Increased stratification of temperature layers within the water column resulted in increased forage efforts by the seals through relatively high numbers of dives to the seafloor, as well as forage effort associated with shallow dives. We interpret these behavioural responses to be due to increased water temperature stratification resulting in the concentration of prey species in particular depth layers.

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Section: Divessupporting

confidence: 58%

Hydrographic influences on the summer dive behaviour of Weddell seals (Leptonychotes weddellii) in Atka Bay, Antarctica

et al. 2013

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“…Marine predators whose foraging cannot be observed directly, such as turtles (Fossette et al, 2008;Hochscheid et al, 2005;Myers and Hays, 2006), cetaceans (RopertCoudert et al, 2002), pinnipeds (Liebsch et al, 2007) and diving birds (Shepard et al, 2010;Simeone and Wilson, 2003;Takahashi et al, 2004;Wilson et al, 2002) are represented in most of these studies (but see Ropert-Coudert et al, 2004), the data from which provided valuable information on prey captures. Of the two penguin species that have been fitted with Hall sensors at sea, the Magellanic penguin Spheniscus magellanicus (Simeone and Wilson, 2003;Wilson et al, 2002) and the chinstrap penguin Pygoscelis antarctica (Takahashi et al, 2004), both dived to moderate depths (<100m) and remained for less than 24h at sea each trip, in contrast with king penguins.…”

Section: Discussionmentioning

confidence: 99%

Measuring foraging activity in a deep-diving bird: comparing wiggles, oesophageal temperatures and beak-opening angles as proxies of feeding

Hanuise

Bost

Huin

et al. 2010

Journal of Experimental Biology

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SUMMARYQuantification of prey consumption by marine predators is key to understanding the organisation of ecosystems. This especially concerns penguins, which are major consumers of southern food webs. As direct observation of their feeding activity is not possible, several indirect methods have been developed that take advantage of miniaturised data logging technology, most commonly: detection of (i) anomalies in diving profiles (wiggles), (ii) drops in oesophageal temperature and (iii) the opening of mouth parts (recorded with a Hall sensor). In the present study, we used these three techniques to compare their validity and obtain information about the feeding activity of two free-ranging king penguins (Aptenodytes patagonicus). Crucially, and for the first time, two types of beak-opening events were identified. Type A was believed to correspond to failed prey-capture attempts and type B to successful attempts, because, in nearly all cases, only type B was followed by a drop in oesophageal temperature. The number of beak-opening events, oesophageal temperature drops and wiggles per dive were all correlated. However, for a given dive, the number of wiggles and oesophageal temperature drops were lower than the number of beak-opening events. Our results suggest that recording beak opening is a very accurate method for detecting prey ingestions by diving seabirds at a fine scale. However, these advantages are counterbalanced by the difficulty, and hence potential adverse effects, of instrumenting birds with the necessary sensor/magnet, which is in contrast to the less accurate but more practicable methods of measuring dive profiles or, to a lesser extent, oesophageal temperature.

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“…However, these temperature loggers have certain limits, as they are restricted to endotherms feeding on ectothermic prey and are quite invasive. Furthermore, stomach temperature recorders fail to detect multiple rapid ingestions of small prey and are often regurgitated prematurely (Ropert-Coudert et al 2004, Liebsch et al 2007. External loggers such as the Inter-Mandibular Angle Sensor (IMASEN) record the mouth-opening angle of predators (Wilson et al 2002), but are sometimes difficult to apply on animals with flexible lips (Ropert-Coudert et al 2004, Liebsch et al 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, stomach temperature recorders fail to detect multiple rapid ingestions of small prey and are often regurgitated prematurely (Ropert-Coudert et al 2004, Liebsch et al 2007. External loggers such as the Inter-Mandibular Angle Sensor (IMASEN) record the mouth-opening angle of predators (Wilson et al 2002), but are sometimes difficult to apply on animals with flexible lips (Ropert-Coudert et al 2004, Liebsch et al 2007. Recent studies in free-ranging diving pinnipeds have overcome this methodological issue by using head-or jaw-mounted accelerometers to detect prey encounter events (PEEs) (Suzuki et al 2009, Naito et al 2010, 2013, Viviant et al 2010, Gallon et al 2013, Iwata et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

Guinet¹,

Vacquié‐Garcia²,

Picard³

et al. 2014

Mar. Ecol. Prog. Ser.

102

131

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The distribution of southern elephant seal Mirounga leonina prey encounter events (PEEs) was investigated from the foraging behaviour of 29 post-breeding females simultaneously equipped with a satellite tag, a time−depth recorder and a head-mounted accelerometer. Seal diving depth and PEE were related to water temperature at 200 m (T 200 ), and light level at the surface (L 0 ) and at depth. Approximately half (49%) of all dives were located in waters encompassed between the southern Antarctic Circumpolar Current Front and the Polar Front. Seals dived significantly deeper during the day than at night. Diving and PEE depth increased with increasing T 200 and for a given T 200 according to L 0 and the percentage of surface light reaching 150 m. On average, 540 PEEs per day were recorded. Seals exhibited more PEEs per unit of time spent diving during the twilight period compared with at night, and were least successful during daylight hours. Elephant seals forage in T 200 ranging between −1 and 13°C; however, few PEEs were recorded at depths shallower than 400−500 m at night when the T 200 exceeded 8°C. The diet of female Kerguelen elephant seals appears to be dominated by myctophids (lanternfish), and according to the average mass of their most likely myctophid prey (9 g, Electrona calsbergi and E. antarctica; 30 g Gymnoscopelus nicholsi and G. piabilis), we estimate that seals consumed 4.8−16.1 kg of fish daily. Despite lower catch rates in warmer waters, no relationship was found between the mean T 200 at the scale of the foraging trip and daily or absolute mass gain, suggesting that elephant seals are compensating for lower catch rates by consuming larger/richer prey items in those waters.

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Mouthing off about fish capture: Jaw movement in pinnipeds reveals the real secrets of ingestion

Cited by 61 publications

References 24 publications

Hydrographic influences on the summer dive behaviour of Weddell seals (Leptonychotes weddellii) in Atka Bay, Antarctica

Hydrographic influences on the summer dive behaviour of Weddell seals (Leptonychotes weddellii) in Atka Bay, Antarctica

Measuring foraging activity in a deep-diving bird: comparing wiggles, oesophageal temperatures and beak-opening angles as proxies of feeding

Southern elephant seal foraging success in relation to temperature and light conditions: insight into prey distribution

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