Investigating Annual Diving Behaviour by Hooded Seals (Cystophora cristata) within the Northwest Atlantic Ocean

Andersen, Julie M.; Skern‐Mauritzen, Mette; Boehme, Lars; Wiersma, Yolanda F.; Rosing‐Asvid, Aqqalu; Hammill, Mike O.; Stenson, Garry B.

doi:10.1371/journal.pone.0080438

Cited by 17 publications

(33 citation statements)

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“…Due to the larger size of males, it is expected that they need to feed more than females if they are foraging on similar prey [15]. Although the drift dive frequencies were similar directly after breeding, males have previously been found to perform slightly longer and deeper dives than females during the same time period (see [44]). Our habitat model also showed that male and female NW Atlantic hooded seals have different movement patterns, using different geographical areas.…”

Section: Discussionmentioning

confidence: 99%

“…Andersen et al [44] used First Passage Time (FPT, see [45]) and three habitat variables (geographic location, bottom depth and the Topographic Complexity Index (TCI) to identify such areas based on data from the same dataset as used in this study. FPT is defined as the time an animal uses to cross a circle of a given radius [45], of which the scale of the circle is determined by calculating the animals' average Area Restricted Search (ARS) scale (see [46]).…”

Section: Introductionmentioning

confidence: 99%

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Drift Diving by Hooded Seals (Cystophora cristata) in the Northwest Atlantic Ocean

et al. 2014

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Many pinniped species perform a specific dive type, referred to as a ‘drift dive’, where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calculating the daily change in vertical drift rates over time, which reflects the relative fluctuations in buoyancy of the animal as the proportion of lipids in the body change. Northwest Atlantic hooded seals perform drift dives at regular intervals throughout their annual migration across the Northwest Atlantic Ocean. We found that the daily change in drift rate varied with geographic location and the time of year and that this differed between sexes. Positive changes in buoyancy (reflecting increased lipid stores) were evident throughout their migration range and although overlapping somewhat, they were not statistically associated with high use areas as indicated by First Passage Time (FPT). Differences in the seasonal fluctuations of buoyancy between males and females suggest that they experience a difference in patterns of energy gain and loss during winter and spring, associated with breeding. The fluctuations in buoyancy around the moulting period were similar between sexes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Drift Diving by Hooded Seals (Cystophora cristata) in the Northwest Atlantic Ocean

et al. 2014

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“…Gregr 2011, Roberts et al 2016 (Table 1): (1) ocean depth (Fig. 2); (2) compound topographic index (CTI) -derived from ocean depth (Evans et al 2014), this variable re flects the peaks (high numeric values of CTI), basins (low values), and flat surfaces (intermediate values) of the ocean floor (Moore et al 1991, Gessler et al 1995, Andersen et al 2013 (Fig. 2); (3) sea surface temperature (SST) -average summer water temperature close to the ocean's surface (Fig.…”

Section: Environmental Datamentioning

confidence: 99%

Predicted distribution of whales at risk: identifying priority areas to enhance cetacean monitoring in the Northwest Atlantic Ocean

Gómez¹,

Lawson²,

Kouwenberg³

et al. 2017

Endang. Species. Res.

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Using long-term data from government, non-government, academic, and industry sources, we developed species distribution models (SDMs) to predict priority areas in which to target and enhance blue whale Balaenoptera musculus and northern bottlenose whale Hyperoodon ampullatus monitoring efforts in eastern Canada. Priority areas for blue whales were located primarily on the Scotian Shelf and along the south shelf break in waters off Newfoundland. Priority areas for northern bottlenose whales were identified primarily in areas along the edges of the eastern Scotian Shelf and the Newfoundland and Labrador Shelves, in submarine canyons, and deep basins. The SDM results and the tools presented in this study indicate that there are few conservation areas in eastern Canada that currently protect whales at risk, and that priority areas for blue and northern bottlenose whales overlap with regions where noise-producing activities (shipping and seismic exploration) occur. This study also highlighted large gaps in the cetacean data related to human activities (e.g. seismic survey lines are outdated and recent information from the past 5 to 10 yr is not available). The SDM approach developed in this study can be used as an iterative, adaptive process by including updated data as it becomes available, further refining and validating the SDM results and thereby improve our understanding of the distribution of cetaceans and noise-producing activities in eastern Canada.

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“…Hidden Markov model [58,59], first passage time [60], state space model [61,62]) and used to relate the defined horizontal ARS to particular structures of the environment (e.g. oceanographic features [31,53,63], sea ice [64,65], topography [66,67]). Bailleul et al [36] underlined the importance of integrating a vertical index of foraging effort to better identify foraging areas when studying deep-diving marine predators.…”

Section: Ecological Applicationsmentioning

confidence: 99%

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

et al. 2015

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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.

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Investigating Annual Diving Behaviour by Hooded Seals (Cystophora cristata) within the Northwest Atlantic Ocean

Cited by 17 publications

References 65 publications

Drift Diving by Hooded Seals (Cystophora cristata) in the Northwest Atlantic Ocean

Drift Diving by Hooded Seals (Cystophora cristata) in the Northwest Atlantic Ocean

Predicted distribution of whales at risk: identifying priority areas to enhance cetacean monitoring in the Northwest Atlantic Ocean

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

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