Detecting and Measuring Food and Water Intake in Captive Seals Using Temperature Telemetry

Gales, Rosemary; Renouf, Deane

doi:10.2307/3809275

Cited by 37 publications

(36 citation statements)

References 12 publications

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“…Fish, ice, snow and free water intake could all be identified in four harp seals (Phoca groenlandica) using changes in stomach temperature (Gales and Renouf, 1993). In this study, using only 11 feedings, a significant linear relationship was found between meal mass and the time it took for stomach temperature to recover to preingestion temperature.…”

Section: Introductionmentioning

confidence: 65%

“…instruments have been used frequently on free-ranging marine mammals (Andrews, 1998;Austin et al, 2006;Hedd et al, 1995;Lesage et al, 1999), but only limited effort has been made to validate the technique (Bekkby and Bjørge, 1998;Gales and Renouf, 1993;Hedd et al, 1996). Owing to the complicated nature of interpreting stomach temperature data, including the potential need to distinguish between prey and water ingestion, studies of feeding behavior can be misinterpreted in the absence of validation (Catry et al, 2004;Grémillet and Plös, 1994;Wilson et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, we examined changes in stomach temperature to determine if the mass of prey consumed could be estimated and whether estimates differ between species. Based on previous captive studies (Gales and Renouf, 1993;Hedd et al, 1996), we hypothesized meal mass will significantly affect the area above the curve (integral) created by the stomach temperature deflection (Fig.·1). In addition, based on the physics of heat transfer, the rate of the warming of stomach contents should be related to the temperature difference between the animal and the prey (Wilson et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Identifying and quantifying prey consumption using stomach temperature change in pinnipeds

Kuhn

Costa

2006

Journal of Experimental Biology

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SUMMARY For many marine predators knowledge of foraging behavior is limited to inferences based on changes in diving or movement patterns at sea. This results in an incomplete and potentially inaccurate view of the foraging ecology of a species. This study examined the use of stomach temperature telemetry to identify and quantify prey consumed in both a phocid (northern elephant seal Mirounga angustirostris) and an otariid (California sea lion Zalophus californianus) species. In addition, we used opportunistic water consumption by northern elephant seals to test a method to distinguish between prey and water ingestion. Over 96% of feedings could be identified based on a decline in stomach temperature, even when meals were separated by as little as 70 min. Water consumption was distinguishable from prey consumption, as the rate of recovery in stomach temperature was significantly faster for water (F1,142=79.2, P<0.01). However, using this method, the overlap in recovery rates between prey and water resulted in 30.6% of water ingestion events being misclassified as prey ingestion. For both species, the integral calculated from the decline in stomach temperature over time (area above the curve) could be used to estimate mass consumed, when adjusted for the temperature difference between the prey and core body temperature. For California sea lions, there was a significant effect of individual on the ability to quantify prey consumed, which was not related to their mass or sex. Although many factors may influence the ability to use stomach temperature change to identify and quantify prey consumed, this study has shown measures of stomach temperature can accurately identify prey consumption and provide an estimate of meal mass, allowing for a greater understanding of the feeding behavior of marine mammals.

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Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identifying and quantifying prey consumption using stomach temperature change in pinnipeds

Kuhn

Costa

2006

Journal of Experimental Biology

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“…Different methodologies have attempted to elucidate this in marine animals, including stomach temperature sensors (Wilson et al, 1992;Gales and Renouf, 1993;Gremillet and Pios, 1994;Wilson et al, 1995), oesophageal temperature sensors (Ancel et al, 1997), and jaw muscle sensors (Bornemann et al, 1992;Plo¨tz et al, 2001). Temperature-based systems are limited to endotherms feeding on ectothermic prey, and all systems either lack fine resolution or are quite invasive.…”

Section: Introductionmentioning

confidence: 99%

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

Liebsch

Wilson

Bornemann

et al. 2007

Deep Sea Research Part II: Topical Studies in Oceanography

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Determination of when and where animals feed and how much they consume is fundamental to understand their ecology and role in ecosystems. However, the lack of reliable data on feeding habits of wild animals, and particularly in marine endotherms, attests to the difficulty in doing this. A promising recent development proposes using a Hall sensor-magnet system, the inter-mandibular angle sensor (IMASEN) attached to animals' jaws to elucidate feeding events. We conducted trials on captive pinnipeds by feeding IMASEN-equipped animals with prey to examine the utility of this system. Most feeding events were clearly distinguishable from other jaw movements; only small prey items might not be resolved adequately. Based on the results of this study we examined feeding events from free-ranging pinnipeds fitted with IMASENs and dead-reckoners and present data on prey capture and ingestion in relation to the three-dimensional movement patterns of the seals. r

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“…Prey ingestion has been estimated by measuring changes in stomach or oesophageal temperature in seabirds (Garthe et al, 1999;Weimerskirch and Wilson, 1992;Wilson, 1992), sharks (Klimley et al, 2001), penguins (Charrassin et al, 2001;Putz and Bost, 1994;Putz et al, 1998), turtles (Tanaka et al, 1995) and seals (Bekkby and Bjorge, 1998;Gales and Renouf, 1993;Hedd et al, 1996). Although these techniques are useful for recording the timing of feeding events, estimates of meal size have generally been less reliable (Wilson et al, 1995), and the technique is further hampered by short retention times of stomach tags .…”

mentioning

confidence: 99%

Blubber and buoyancy: monitoring the body condition of free-ranging seals using simple dive characteristics

Biuw

McConnell

Bradshaw

et al. 2003

Journal of Experimental Biology

163

323

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With the development of time depth recorders (Kooyman, 1965) and satellite, radio and acoustic telemetry (e.g. Fancy et al., 1988;Fedak, 1992;Fedak et al., 1983;McConnell, 1986), it is now possible to study the behaviour of many free-ranging marine organisms. Although these data have provided new insights into the foraging ecology of marine species, there are still limitations in the types of information that can be collected. Specifically, direct observation or recording of feeding events is often impossible (particularly for animals ranging over large areas during extended trips), and it is consequently difficult to determine where and when individuals encounter and ingest food and how much of this is assimilated into the body energy stores. In some cases, instrumented individuals can be recaptured when they return to land, and their net growth, energy expenditure and change in body condition can be estimated and correlated with at-sea behaviour (Bost et al., 1997;Boyd et al., 1993;Boyd and Arnbom, 1991;Chappell et al., 1993;Kooyman et al., 1992;Le Boeuf et al., 2000). However, this only provides information on the relationship between body condition and the behaviour and movements integrated over months and thousands of kilometres, while we are frequently interested in Elephant seals regularly perform dives during which they spend a large proportion of time drifting passively through the water column. The rate of vertical change in depth during these 'drift' dives is largely a result of the proportion of lipid tissue in the body, with fatter seals having higher (more positive or less negative) drift rates compared with leaner seals. We examined the temporal changes in drift rates of 24 newly weaned southern elephant seal (Mirounga leonina) pups during their first trip to sea to determine if this easily recorded dive characteristic can be used to continuously monitor changes in body composition of seals throughout their foraging trips. All seals demonstrated a similar trend over time: drift rates were initially positive but decreased steadily over the first 30-50 days after departure (Phase 1), corresponding to seals becoming gradually less buoyant. Over the following ~100·days (Phase 2), drift rates again increased gradually, while during the last 20-45·days (Phase 3) drift rates either remained constant or decreased slightly. The daily rate of change in drift rate was negatively related to the daily rate of horizontal displacement (daily travel rate), and daily travel rates of more than ~80·km were almost exclusively associated with negative changes in drift rate. We developed a mechanistic model based on body compositions and morphometrics measured in the field, published values for the density of seawater and various body components, and values of drag coefficients for objects of different shapes. We used this model to examine the theoretical relationships between drift rate and body composition and carried out a sensitivity analysis to quantify errors and biases caused by varying model parameters. While v...

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Detecting and Measuring Food and Water Intake in Captive Seals Using Temperature Telemetry

Cited by 37 publications

References 12 publications

Identifying and quantifying prey consumption using stomach temperature change in pinnipeds

Identifying and quantifying prey consumption using stomach temperature change in pinnipeds

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

Blubber and buoyancy: monitoring the body condition of free-ranging seals using simple dive characteristics

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