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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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Duration (min) of dives of Baltic ringed seals (excluding females from the Bothnian Bay).About 70% of male dives lasted longer than 2 min in early summer, which decreased to 30% in October. An increase to about 50% was seen up to December, after which dive durations decreased markedly up to March. A similar pattern was seen in females, but dives lasted longer in December and January. About 10% of male dives lasted longer than 10 min in the period from June to September, compared with 0.8% for females.
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pone-0002006-g003: Duration (min) of dives of Baltic ringed seals (excluding females from the Bothnian Bay).About 70% of male dives lasted longer than 2 min in early summer, which decreased to 30% in October. An increase to about 50% was seen up to December, after which dive durations decreased markedly up to March. A similar pattern was seen in females, but dives lasted longer in December and January. About 10% of male dives lasted longer than 10 min in the period from June to September, compared with 0.8% for females.

Mentions: For the two southern areas the duration of dives also showed strong seasonal variations for both sexes. In females, dives longer than 2 min decreased from 70% in June to less than 40% in October, after which the proportion of longer dives increased again between November and January (Fig. 3). However, in February about 80% of dives were shorter than 2 min. The pattern for males was basically similar, although male dives lasted longer in the summer and were shortest in February–March. Frequencies of the longest dives peaked in the summer (June to August) for both sexes, although only 1.7% of male dives and 0.15% of female dives lasted for more than 25 min.


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)

Duration (min) of dives of Baltic ringed seals (excluding females from the Bothnian Bay).About 70% of male dives lasted longer than 2 min in early summer, which decreased to 30% in October. An increase to about 50% was seen up to December, after which dive durations decreased markedly up to March. A similar pattern was seen in females, but dives lasted longer in December and January. About 10% of male dives lasted longer than 10 min in the period from June to September, compared with 0.8% for females.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0002006-g003: Duration (min) of dives of Baltic ringed seals (excluding females from the Bothnian Bay).About 70% of male dives lasted longer than 2 min in early summer, which decreased to 30% in October. An increase to about 50% was seen up to December, after which dive durations decreased markedly up to March. A similar pattern was seen in females, but dives lasted longer in December and January. About 10% of male dives lasted longer than 10 min in the period from June to September, compared with 0.8% for females.
Mentions: For the two southern areas the duration of dives also showed strong seasonal variations for both sexes. In females, dives longer than 2 min decreased from 70% in June to less than 40% in October, after which the proportion of longer dives increased again between November and January (Fig. 3). However, in February about 80% of dives were shorter than 2 min. The pattern for males was basically similar, although male dives lasted longer in the summer and were shortest in February–March. Frequencies of the longest dives peaked in the summer (June to August) for both sexes, although only 1.7% of male dives and 0.15% of female dives lasted for more than 25 min.

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