Seasonal Activity Budget of Adult Baltic Ringed Seals

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.

Haulout patterns of Saimaa ringed seals and their response to boat traffic during the moulting season

“…During moulting, haulout activity of ringed seals typically peaks in the afternoon (Smith 1973a,b, Finley 1979, Smith & Hammill 1981, Kelly & Quakenbush 1990, Lydersen 1991, Belikov & Boltunov 1998 Carlens et al 2006, Kelly et al 2010), but the seals exhibit a nocturnal haulout pattern after the moult (Hyvärinen et al 1995, Härkönen et al 2008, which was supported by the present study. Conversely, ringed seals in Greenland have not shown any circadian rhythm in their haulout behaviour (Heide-Jørgensen et al 1992, Born et al 2002.…”

Factors influencing the winter haulout behaviour of Weddell seals: consequences for satellite telemetry

“…data), the peak in haulout at midafternoon when solar radiation is at its greatest allows for a more efficient moult as skin temperature is increased (Feltz & Fay 1966, Schneider & Payne 1983, Boily 1995. Nocturnal haulout as a general behaviour has been described for a number of northern hemisphere seals, including the Saimaa seal Phoca hispida saimensis (Kunnasranta et al 2002), the Baltic grey seal Halichoerus grypus (Sjöberg et al 1995), captive harp seals Pagophilus groenlandicus (Moulton et al 2000) and Baltic ringed seals Phoca hispida botnica (Harkonen et al 2008), and in these cases, was considered a response to prey behaviour, disturbance and weather.…”

“…crabeater seal, Burns et al 2004; Baltic ringed seal Phoca hispida botnica, Harkonen et al 2008; leopard seal Hydrurga leptonyx, Nordøy et al 2009). However, the behavioural state may influence data acquisition, as transmission conditions are more favourable when the animals are hauled out or in shallow water (Tougaard et al 2008).…”

Combined Genetic and Telemetry Data Reveal High Rates of Gene Flow, Migration, and Long-Distance Dispersal Potential in Arctic Ringed Seals (Pusa hispida)

“…Ringed seal haulout and diving activity provides insights into interactions with other trophic levels, with diel diving behavior linked to seasonal activity budget and the vertical distribution of prey items [26]. The abundance and distribution of ringed seals is attributed to their highly variable feeding habits and diverse prey items, the foremost of which are: arctic, polar, and saffron cod, Decapods, Euphausiids, and large Amphipods [27]–[29].…”