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Seasonal activity budget of adult baltic ringed seals.

Harkonen T, Jüssi M, Jüssi I, Verevkin M, Dmitrieva L, Helle E, Sagitov R, Harding KC - PLoS ONE (2008)

Bottom Line: Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks.Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn.The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

View Article: PubMed Central - PubMed

Affiliation: Swedish Museum of Natural History, Stockholm, Sweden. tero.harkonen@nrm.se

ABSTRACT
Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

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Related in: MedlinePlus

Weight of ringed seal females caught in the open water season.Filled circles refer to data from this study (PS), and open circles are data compiled from the seal data base at the Swedish Museum of Natural History (NRM). A linear regression of pooled data (y = 9.16x−7.97, R2 = 0.83) suggest that ringed seal females gain 9.2 kg per month from May up to December.
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pone-0002006-g011: Weight of ringed seal females caught in the open water season.Filled circles refer to data from this study (PS), and open circles are data compiled from the seal data base at the Swedish Museum of Natural History (NRM). A linear regression of pooled data (y = 9.16x−7.97, R2 = 0.83) suggest that ringed seal females gain 9.2 kg per month from May up to December.

Mentions: The proportion of time diving deeper than 2 m, time spent at surface, and time hauled out from figs 6, 8, and 11. “Shallow” denotes dives in the interval 1–2 m, and is given by 100% minus the sum of all other activities.


Seasonal activity budget of adult baltic ringed seals.

Harkonen T, Jüssi M, Jüssi I, Verevkin M, Dmitrieva L, Helle E, Sagitov R, Harding KC - PLoS ONE (2008)

Weight of ringed seal females caught in the open water season.Filled circles refer to data from this study (PS), and open circles are data compiled from the seal data base at the Swedish Museum of Natural History (NRM). A linear regression of pooled data (y = 9.16x−7.97, R2 = 0.83) suggest that ringed seal females gain 9.2 kg per month from May up to December.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2289877&req=5

pone-0002006-g011: Weight of ringed seal females caught in the open water season.Filled circles refer to data from this study (PS), and open circles are data compiled from the seal data base at the Swedish Museum of Natural History (NRM). A linear regression of pooled data (y = 9.16x−7.97, R2 = 0.83) suggest that ringed seal females gain 9.2 kg per month from May up to December.
Mentions: The proportion of time diving deeper than 2 m, time spent at surface, and time hauled out from figs 6, 8, and 11. “Shallow” denotes dives in the interval 1–2 m, and is given by 100% minus the sum of all other activities.

Bottom Line: Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks.Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn.The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

View Article: PubMed Central - PubMed

Affiliation: Swedish Museum of Natural History, Stockholm, Sweden. tero.harkonen@nrm.se

ABSTRACT
Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

Show MeSH
Related in: MedlinePlus