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

Guinet, Christophe; Vacquié‐Garcia, Jade; Picard, Baptiste; Bessigneul, Guillaume; Lebras, Y.; Dragon, Anne Cécile; Viviant, Morgane; Arnould, John P. Y.; Bailleul, Frédéric

doi:10.3354/meps10660

Cited by 103 publications

(143 citation statements)

References 75 publications

Supporting

Mentioning

131

Contrasting

Order By: Relevance

“…We suggest that during the summer seals adopt a hierarchical foraging strategy by responding to large-scale biological cues during late spring/summer phytoplankton bloom periods in order to locate profitable prey fields at the smaller scale. These findings are consistent with Guinet et al (2014) which showed summer seals (females) feeding during the day are more successful (indicated by prey capture attempts derived from accelerometer data) in areas where higher concentration of particles (indicted by the influence of plankton density on light attenuation) are encountered, but did not however consider females feeding in winter.…”

Section: Seasonally-contrasted Foraging Strategies In Relation To Ressupporting

confidence: 80%

“…Due to distinct biological change between the summer bloom period and the winter post-bloom period, we expect fundamental differences in SES foraging strategy in relation to seasonal plankton densities. The diet of female SES is thought to consist largely of mesopelagic fish, primarily myctophid, during the two foraging periods (Cherel et al, 2008;Guinet et al, 2014). Therefore, seasonal changes in seal behavior may be indicative of a change in the prey field distribution relative to lower trophic (i.e., plankton) distribution.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Foraging strategy switch of a top marine predator according to seasonal resource differences

et al. 2015

View full text Add to dashboard Cite

The spatio-temporal variability in marine resources influences the foraging behavior and success of top marine predators. However, little is known about the links between these animals and ocean productivity, specifically, how plankton density influences their foraging behavior. Southern elephant seals (Mirounga leonina) have two annual at-sea foraging trips: a 2 month post-breeding foraging trip (Nov-Jan) that coincides with elevated summer productivity; and an 8 month post-molting foraging trip (Feb-Oct) over winter, when productivity is low. Physical parameters are often used to describe seal habitat, whereas information about important biological parameters is lacking. We used electronic tags deployed on elephant seals during both trips to determine their movement and foraging behavior. The tags also recorded light, which measured the bio-optical properties of the water column, the bulk of which is presumably influenced by phytoplankton. We investigated the relationship between plankton density and seal foraging behavior; comparing trends between summer and winter trips. We found a positive relationship between plankton density and foraging behavior, which did not vary seasonally. We propose that profitable concentrations of seal prey are more likely to coincide with planktonic aggregations, but we also acknowledge that trophic dynamics may shift in response to seasonal trends in productivity. Seal prey (mid-trophic level) and plankton (lower-trophic level) are expected to overlap in space and time during summer trips when peak phytoplankton blooms occur. In contrast, aggregated patches of lower trophic levels are likely to be more dispersed during winter trips when plankton density is considerably lower and heterogeneous. These results show that southern elephant seals are able to exploit prey resources in different ways throughout the year as demonstrated by the variation observed between seal foraging behavior and trophic dynamics.

show abstract

Section: Seasonally-contrasted Foraging Strategies In Relation To Ressupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Foraging strategy switch of a top marine predator according to seasonal resource differences

et al. 2015

View full text Add to dashboard Cite

show abstract

“…During the last decade, satellite-relayed data loggers (SRDLs) have been widely used for transmitting, in near real time, data on the behaviour of marine predators, most typically dive depth and duration, but also in some cases swimming speed or ocean data such as temperature and salinity [6,8]. The miniaturisation, extended battery life and memory capacity of these devices allow the collection and storage of data at very high resolutions (1 s or less) and for long periods of time (several months) [5,8,9]. However, the limited time and bandwidth available for data transmission at the surface imposed by both the animal's diving habits and CLS Argos restrict the amount of data that can be sent [6,10].…”

Section: Open Accessmentioning

confidence: 99%

From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators

et al. 2015

View full text Add to dashboard Cite

Background: In the last decade, thousands of satellite-relayed data loggers (SRDLs) have been deployed, providing large datasets on marine predator movement patterns at sea and their diving behaviour. However, the latter is in a highly summarised, low-resolution form, from which it is difficult to make the sorts of important behavioural inferences that are possible from higher-resolution datasets (such as detection of likely foraging events). The main objective of this study was to develop a simple, but accurate tool to detect and quantify within-dive foraging periods in low-resolution dives.Method: Two southern elephant seals were fitted with a head-mounted time depth recorder (TDR) (recording depth at 1 Hz) and an accelerometer (recording 3 axes of acceleration at 16 Hz) from which prey capture attempts were estimated (PrCA), and a Weddell seal was also fitted with a TDR (1 Hz).The resulting high-resolution dive profiles were used to: (1) calculate an accurate index of foraging effort based on the detection of vertical sinuosity switches (i.e. hunting highres time); (2) produce an SRDL-equivalent low-resolution dataset using a broken stick algorithm; and (3) from each low-resolution dive calculate a set of candidate foraging effort indices.Results: Hunting lowres time, which is the total time spent in decreased vertical velocity segments of the dive, was the foraging effort index that best correlated with hunting highres time. Hunting highres mode of SES dives (highly sinuous parts of high-resolution dives) was associated with 77 % of total PrCA. In comparison, Hunting lowres segments of SES dives were associated with 68 % of PrCA as well as with four times more PrCA than transit lowres segments. Conclusion:We found a low-resolution index which indicates foraging activity within a highly summarised dive profile and which identified most PrCA, despite degraded information transmitted by SLDRs. Used in combination with other measurements of the in situ environment, the hunting lowres index could be used in numerous integrated marine ecology studies, such as habitat use studies that are crucial to facilitate more effective conservation.

show abstract

“…The procedureis described in detail in Guinet et al (2014). Regardless of the axis, the recorded acceleration is composed of 2 types of acceleration: static and dynamic.…”

Section: Acceleration Datamentioning

confidence: 99%

“…Indeed, these loggers are focused on measuring prey capture attempts (PCAs), which is currently considered as the best proxy for foraging success (see Guinet et al 2014 where prey encounter events [PEE] correspond to PCA). However, the aforementioned devices may also have some restrictions.…”

Section: Introductionmentioning

confidence: 99%

Predicting prey capture rates of southern elephant seals from track and dive parameters

Vacquié‐Garcia¹,

Guinet²,

Dragon³

et al. 2015

Mar. Ecol. Prog. Ser.

Self Cite

View full text Add to dashboard Cite

In the marine environment, track and dive parameter data (obtained using Argos or GPS tags and time-depth recorders) are commonly used to provide proxies for foraging behaviour of marine predators. However, their accuracy is rarely assessed. Recently, the addition of headmounted accelerometers has allowed for detection of prey capture attempts (PCAs) at sea, allowing for more accurate estimations of foraging behaviour. Despite increased numbers of such devices being deployed, their use is still marginal compared with other tools which measure track and dive parameters. The objectives of our study were (1) to identify the most relevant combination of tracking and diving metrics in predicting the frequency of PCAs in female southern elephant seals Mirounga leonina from the Kerguelen Islands, and (2) to apply it to a broader range of individuals for which only tracking and diving data were available. The results of our models were consistent with the optimal foraging theory as well as the optimal diving theory. The model with the best predictive performance was the one that combined both tracking and diving information. However, most of the variability in the number of PCAs could be solely explained by changes in the diving behaviour of seals. Finally, we used the best predictive model on 20 individuals, which had not been fitted with accelerometers, to determine their main foraging zones. The behavioural indicators established in this study constitute a useful ecological tool for population monitoring and conservation purposes.

show abstract

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

Cited by 103 publications

References 75 publications

Foraging strategy switch of a top marine predator according to seasonal resource differences

Foraging strategy switch of a top marine predator according to seasonal resource differences

From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators

Predicting prey capture rates of southern elephant seals from track and dive parameters

Contact Info

Product

Resources

About