Limits...
Options for modulating intra-specific competition in colonial pinnipeds: the case of harbour seals (Phoca vitulina) in the Wadden Sea.

Wilson RP, Liebsch N, Gómez-Laich A, Kay WP, Bone A, Hobson VJ, Siebert U - PeerJ (2015)

Bottom Line: We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders.Males also had higher vertical descent rates.This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK ; GEOMAR Helmholtz Centre for Ocean Research, Düsternbrooker , Kiel , Germany.

ABSTRACT
Colonial pinnipeds may be subject to substantial consumptive competition because they are large, slow-moving central place foragers. We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders. Analysis of 319,021 dives revealed little between-colony variation but appreciable inter-sex differences, with males diving deeper than females, but for shorter periods. Males also had higher vertical descent rates. This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females. Intersex variation in swim speed alone is predicted to lead to fundamental differences in the time use of three-dimensional space, which may help reduce consumptive competition in harbour seals and other colonial pinnipeds.

No MeSH data available.


Related in: MedlinePlus

Frequency distribution of the maximum depth and dive duration of U-dives.Frequency distribution of (A) the maximum depth (B) and dive duration of U-dives performed by female (black bars) and male. (grey bars) harbour seals
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4465952&req=5

fig-2: Frequency distribution of the maximum depth and dive duration of U-dives.Frequency distribution of (A) the maximum depth (B) and dive duration of U-dives performed by female (black bars) and male. (grey bars) harbour seals

Mentions: During their U-dives, males went significantly deeper than females (LMM, Sex effect F1,31 = 4.4, p = 0.04) (Fig. 2A), with no differences in these depths between the three studied sites (LMM, Site effect F1,31 = 0.01, p = 0.9). Mean maximum dive depths were 17.5 ± 2.5, 13.4 ± 3.6 and 19 ± 9 m for males, compared with 12.6, 13.4 ± 3.4 and 8.8 ± 3.5 m for females, from DK, LP and HE, respectively.


Options for modulating intra-specific competition in colonial pinnipeds: the case of harbour seals (Phoca vitulina) in the Wadden Sea.

Wilson RP, Liebsch N, Gómez-Laich A, Kay WP, Bone A, Hobson VJ, Siebert U - PeerJ (2015)

Frequency distribution of the maximum depth and dive duration of U-dives.Frequency distribution of (A) the maximum depth (B) and dive duration of U-dives performed by female (black bars) and male. (grey bars) harbour seals
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465952&req=5

fig-2: Frequency distribution of the maximum depth and dive duration of U-dives.Frequency distribution of (A) the maximum depth (B) and dive duration of U-dives performed by female (black bars) and male. (grey bars) harbour seals
Mentions: During their U-dives, males went significantly deeper than females (LMM, Sex effect F1,31 = 4.4, p = 0.04) (Fig. 2A), with no differences in these depths between the three studied sites (LMM, Site effect F1,31 = 0.01, p = 0.9). Mean maximum dive depths were 17.5 ± 2.5, 13.4 ± 3.6 and 19 ± 9 m for males, compared with 12.6, 13.4 ± 3.4 and 8.8 ± 3.5 m for females, from DK, LP and HE, respectively.

Bottom Line: We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders.Males also had higher vertical descent rates.This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK ; GEOMAR Helmholtz Centre for Ocean Research, Düsternbrooker , Kiel , Germany.

ABSTRACT
Colonial pinnipeds may be subject to substantial consumptive competition because they are large, slow-moving central place foragers. We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders. Analysis of 319,021 dives revealed little between-colony variation but appreciable inter-sex differences, with males diving deeper than females, but for shorter periods. Males also had higher vertical descent rates. This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females. Intersex variation in swim speed alone is predicted to lead to fundamental differences in the time use of three-dimensional space, which may help reduce consumptive competition in harbour seals and other colonial pinnipeds.

No MeSH data available.


Related in: MedlinePlus