Variations in harbour seal Phoca vitulina diet and dive-depths in relation to foraging habitat

Tollit, Dominic J.; Black, Andrew; Thompson, Paul M.; Mackay, Ann; Corpe, H. M.; Wilson, Ben; Parijs, Sofie M. Van; Grellier, Kate; Parlane, S.

doi:10.1017/s0952836998002064

Cited by 42 publications

(58 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, although sample sizes were small and individual variability high, foraging adult females were located in broadly similar areas and travelled similar distances in 1989 and 2009. The relative local foraging seen in both years is consistent with previous tracking work of harbour seals in the Moray Firth (Tollit et al, 1998) and elsewhere (Lesage, Hammill & Kovacs, 2004). …”

Section: Discussionsupporting

confidence: 89%

Long‐term patterns in harbour seal site‐use and the consequences for managing protected areas

Cordes

Duck

Mackey

et al. 2011

Animal Conservation

Self Cite

View full text Add to dashboard Cite

There have been marked declines of UK harbour seal populations over at least the last decade. Protected areas, such as Special Areas of Conservation (SACs), provide one tool to improve the conservation status of these populations. However, the design and management of SACs is often limited by a lack of information on long-term patterns in the use of seal haul-out sites and foraging areas. The Moray Firth is the only UK region where long-term harbour seal population studies have been conducted in parallel with detailed studies of foraging ecology. We used this opportunity to investigate changes in the use of haul-out sites and foraging areas within two adjacent estuaries, where annual haulout counts were made over a 20-year period. In 1988, 499% of seals and all mother-pup pairs were located at haul-out sites within an area that was subsequently designated as a SAC to protect harbour seals. In addition to previously reported declines in this area, we detected a shift in haul-out distribution resulting from the development of a new pupping site that, by 2008, held 37% of mother pup pairs in the area. Foraging areas of breeding females were compared in 1989 and 2009 using a combination of VHF and GPS-GSM telemetry, confirming that females foraged in broadly similar areas in both periods. This suggests that the development of this new pupping site was not driven by the need to forage further offshore, but instead was more likely due to local variation in haul-out site characteristics. These results are discussed in relation to potential drivers of haulout site choice and the need to develop a broader suite of measures for managing habitat quality within this and other SACs for harbour seals.

show abstract

Section: Discussionsupporting

confidence: 89%

Long‐term patterns in harbour seal site‐use and the consequences for managing protected areas

Cordes

Duck

Mackey

et al. 2011

Animal Conservation

Self Cite

View full text Add to dashboard Cite

show abstract

“…As a consequence seabirds exhibit considerable variation in their foraging behaviour or at-sea distribution. Prey availability is related to the physical and biological properties of the ocean, such as depth (Hastie et al 2003), hydrological structure (Charrassin and Bost 2001), and substrate type (Tollit et al 1998) and, in near-shore waters, tidal effects (Chen et al 1999;Holm and Burger 2002;Zamon 2003). Therefore, habitat utilisation by predators is assumed to reflect the quality and availability of resources in an area (Davoren et al 2003;Laidre et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Foraging movements of Magellanic Penguins Spheniscus magellanicus in the Beagle Channel, Argentina, related to tide and tidal currents

et al. 2010

View full text Add to dashboard Cite

This study investigates the movements of Magellanic Penguins Spheniscus magellanicus breeding on Isla Martillo during the early chick-rearing period. Foraging paths were reconstructed using GPS loggers that registered the penguins 0 geographic position, water temperature and depth at regular intervals. The relationship between penguins 0 movements and search strategies, tide and tidal currents were assessed. Mean trip duration was on average 14.7 ± 6.9 h (33% overnight), and the maximum distance reached was 24 ± 10 km. All penguins studied foraged to the east of the colony. We identified three phases based on the sinuosity and speed of the trajectory: transit, central and return. Foraging effort was higher during the central phase, followed by the transit phase, and lower in the return phase. Foraging success, measured as the percentage of time at the bottom during each phase, was also highest during the central phase. In all birds studied, the central phase of the foraging trip took place during ebb tide, and birds travelled to the foraging areas with flow tide running in the same direction of displacement. Our study suggests that penguins take advantage of tidal currents to facilitate their movements to and from the main foraging area, thereby reducing the energy expended. Moreover, we suggest that piscivorous diving birds may enhance their catch rate during ebb tide when fish are more concentrated near the channel bed.

show abstract

“…Our study provides a different suite of analyses than previously published and contributes to the growing body of literature that identifies harbor seals as generalist predators (e.g., Andersen et al, 2004;Berg et al, 2002;Jemison, 2001;Lance and Jeffries, 2007;London et al, 2002;Pitcher, 1980;Tollit et al, 1998;Wright et al, 2007). Nonetheless, only a fraction of the various prey species consumed by harbor seals have been consistently identified as dominating the diet of the average seal (Andersen et al, 2004;Jemison, 2001;Pitcher, 1980).…”

Section: Discussionmentioning

confidence: 76%

“…Harbor seals are opportunistic predators, readily capitalizing on a wide variety of prey species from both benthic and pelagic habitats, including sculpins (Cottidae), flatfishes (Pleuronectidae), cephalopods, salmon (Oncorhynchus spp. ), and Pacific sand lance (Ammodytes hexapterus) (Andersen et al, 2004;Berg et al, 2002;Herreman et al, 2009;Jemison, 2001;Lance and Jeffries, 2007;London et al, 2002;Pitcher, 1980;Tollit et al, 1998;Wright et al, 2007). Although many prey species have been identified in diets, often only a few of these prey items are present consistently enough to be considered principal prey items in the typical harbor seal diet (Andersen et al, 2004;Jemison, 2001;Pitcher, 1980).…”

Section: Introductionmentioning

confidence: 99%

A new method to evaluate the nutritional composition of marine mammal diets from scats applied to harbor seals in the Gulf of Alaska

Geiger

Atkinson

Waite

et al. 2013

Journal of Experimental Marine Biology and Ecology

View full text Add to dashboard Cite

Variations in harbour seal Phoca vitulina diet and dive-depths in relation to foraging habitat

Cited by 42 publications

References 0 publications

Long‐term patterns in harbour seal site‐use and the consequences for managing protected areas

Long‐term patterns in harbour seal site‐use and the consequences for managing protected areas

Foraging movements of Magellanic Penguins Spheniscus magellanicus in the Beagle Channel, Argentina, related to tide and tidal currents

A new method to evaluate the nutritional composition of marine mammal diets from scats applied to harbor seals in the Gulf of Alaska

Contact Info

Product

Resources

About