Limits...
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.

Show MeSH
Proportions of dives to depth intervals from 2–5 m to more than 80 m of adult ringed seals.Females tagged in the Bothnian Bay (BB) not included. More than 90% of male dives were deeper than 5 m in June, which changed to 25% in October to again increase to about 80% in March. A similar flux was evident in females, but the dives were generally shallower than for males.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2289877&req=5

pone-0002006-g002: Proportions of dives to depth intervals from 2–5 m to more than 80 m of adult ringed seals.Females tagged in the Bothnian Bay (BB) not included. More than 90% of male dives were deeper than 5 m in June, which changed to 25% in October to again increase to about 80% in March. A similar flux was evident in females, but the dives were generally shallower than for males.

Mentions: Most dives of females were shallow (<10 m) over the year, but numerous dives were also found in the >20 m–40 m bin (Fig. 2). In May 37% of female dives were deeper than 10 m, but the proportion increased to 64 and 57% in June and July, respectively (Fig. 2). Also the frequencies of the deepest dives (>80 m) peaked during this period of the year. In late summer and in the autumn deeper dives became scarce, and in October only 7% of dives were deeper than 10 m. This proportion increased gradually during the winter and in January 31% of the dives were deeper than 10 m. Males showed basically the same pattern as found for females. The major difference was that the frequencies of deeper dives in June and July were higher for males compared to females. During winter the dives of the males were even shallower than for the females.


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)

Proportions of dives to depth intervals from 2–5 m to more than 80 m of adult ringed seals.Females tagged in the Bothnian Bay (BB) not included. More than 90% of male dives were deeper than 5 m in June, which changed to 25% in October to again increase to about 80% in March. A similar flux was evident in females, but the dives were generally shallower than for males.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0002006-g002: Proportions of dives to depth intervals from 2–5 m to more than 80 m of adult ringed seals.Females tagged in the Bothnian Bay (BB) not included. More than 90% of male dives were deeper than 5 m in June, which changed to 25% in October to again increase to about 80% in March. A similar flux was evident in females, but the dives were generally shallower than for males.
Mentions: Most dives of females were shallow (<10 m) over the year, but numerous dives were also found in the >20 m–40 m bin (Fig. 2). In May 37% of female dives were deeper than 10 m, but the proportion increased to 64 and 57% in June and July, respectively (Fig. 2). Also the frequencies of the deepest dives (>80 m) peaked during this period of the year. In late summer and in the autumn deeper dives became scarce, and in October only 7% of dives were deeper than 10 m. This proportion increased gradually during the winter and in January 31% of the dives were deeper than 10 m. Males showed basically the same pattern as found for females. The major difference was that the frequencies of deeper dives in June and July were higher for males compared to females. During winter the dives of the males were even shallower than for the females.

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