The importance of the “Polar Front” as a foraging habitat for guillemots Uria spp. breeding at Bjørnøya, Barents Sea

Mehlum, Fridtjof; Nordlund, Nina; Isaksen, Kjell

doi:10.1016/s0924-7963(98)00017-7

Cited by 18 publications

(15 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Georges & S. Mangin unpubl, data). This is consistent with previous studies indicating that abundance and activity of seabirds (Abrams 1985, Mehlum et al 1998) and marine mammals (Machida 1974, Boyd & Arnbom 1991, McConnell et al 1992, Tynan 1998 are associated with frontal struc-tures. This also indicates that for most top predators, such as fur seals, food requirements can only be sustained by highly productive and seasonaly predictable oceanographic features, as proposed for whales (Tynan 1998), penguins and seals (Pakhomov & Froneman 1999).…”

Section: Foraging Habitat and Oceanographic Featuressupporting

confidence: 93%

Foraging habitat and diving activity of lactating Subantarctic fur seals in relation to sea-surface temperatures at Amsterdam Island

Georges¹,

Bonadonna²,

Guinet³

2000

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

This study investigates the foraging behaviour of lactating Subantarctic fur seals Arctocephalus tropicalis breeding on Amsterdam Island, Indlan Ocean, in relation to sea-surface temperatures (SST) of the surrounding waters over 3 consecutive breeding years (1995 to 1997). Foraging habitat and diving activity were investigated using time depth temperature recorders (TDRs), deployed on 29 individuals during the first trip after parturition in December (n = 7), later in the summer (n = 13), and in winter (n = 9). Argos satellite transmitters (n = 4) and a direction recorder (n = l ) were also used in the 1995 and 1996 austral summers, respectively. Sea temperatures recorded by TDRs in conjunction with the IGOSS SST database were used as a locational cue to estimate the foraging range. The foraging habitat of lactating females was associated with the northern part of the Subtropical Front (STF) (axial SST = 14.2"C), where their main prey, myctophid fish, are known to be abundant. The organisation of the foraging trips, in terms of diving activity, showed seasonal changes but remained similar among years. During the first trip after parturition, females foraged within the STF, 60 to 130 km from the colony, and exhibited a diving activity that d~d not vary significantly throughout the trip. Later in summer, when STF was south of Amsterdam Island, most females tra.velled in a straight south-east direction without diving (suggesting that they travelled regularly to reach a known area). They then concentrated their diving activity in the middle of the STF during 50% of the foraging trip duration, and continued diving on the return trip to the colony. In wmter, the 14°C surface isotherm was 250 km north of Amsterdam Island and SST gradient was very low. Females increased t h e~r foraging range up to 530 km, and there was no evidence for females concentrating their dlving activity within a given area, suggesting thdt they did not encounter dense patches of prey. In winter, seals also increased their diving effort probably in response to a decrease in food availability. Annual changes in SST surrounding Amsterdam Island, and in the surface temperature gradient of the STF appear to affect the time spent at sea, and the relative diving activity throughout the trips in summer. These results suggest that Subantarctic fur seals adjust their foraging behaviour according to both seasonal and annual changes in oceanographic conditions, and thus probably, food availability.

show abstract

Section: Foraging Habitat and Oceanographic Featuressupporting

confidence: 93%

Foraging habitat and diving activity of lactating Subantarctic fur seals in relation to sea-surface temperatures at Amsterdam Island

Georges¹,

Bonadonna²,

Guinet³

2000

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…They proposed that murres restricted their foraging to frontal regions because prey can be located more predictably within these areas. Similarly, Mehlum et al (1998) found a close relationship between murres breeding at Bjørnøya in the Barents Sea and the polar front. During the spawning migration of capelin in the Barents Sea, the maturing fish migrate through a spectrum of different oceanographic conditions from polar front water-masses through more Atlantic waters and finally spawn in coastal waters.…”

Section: Discussionmentioning

confidence: 73%

“…Decker & Hunt 1996, Hunt et al 1998, Mehlum et al 1998. Most studies on these relationships have been done during the breeding period, when the birds are limited by their duties in the colony .…”

Section: Discussionmentioning

confidence: 99%

Scale-dependent predator-prey interactions: the aggregative response of seabirds to prey under variable prey abundance and patchiness

Fauchald¹,

Erikstad²

2002

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

The aggregative response of seabirds to their prey has frequently been measured through their spatial coherence during ship board surveys. In this study, we investigate the aggregative response of murres Uria spp. to capelin Mallotus villosus in relation to yearly changes in capelin abundance and patchiness from a 9 yr data set collected in the Barents Sea. A recent analysis on the spatial distribution of capelin and murres in the Barents Sea reported a hierarchical patch structure, whereby small-scale patches were nested within patches at larger scales. In the present study we carry out similar analyses for each of the 9 years. During the 9 yr period, the estimated total biomass of capelin varied between 100 000 and 7 300 000 t. We identified 2 hierarchical levels of patchiness with characteristic scales of 200 to 300 km and 70 km respectively. We found close relationships between yearly variation in capelin abundance, capelin patchiness and the concordance between capelin and murres at both levels. The patchiness of capelin, as measured by the first-order spatial autocorrelation, increased with increasing capelin abundance at the large-scale level, and there was a similar tendency at the small-scale level. At the large-scale level, the spatial concordance between murres and capelin increased with both increasing capelin density and increasing capelin patchiness. At the small-scale level, the concordance between murres and capelin increased with increasing capelin patchiness. Our results suggest that increased prey patchiness and increased prey abundance enhance the possibility of murres finding satisfactory capelin concentrations. The reduction in prey patchiness with low prey abundance might force predators to switch to other prey items, and might therefore have a stabilizing effect on predator-prey interactions.

show abstract

“…This stratification was caused by the presence of low-salinity water near the surface above the Atlantic water. Similarly, Mehlum et al (1998) found aggregations of murres at the front around Bjørnøya and in the region of stratified water on the warmer side of the front. Aggregations of foraging murres have also been reported from a frontal zone near large colonies on Novaya Zemlya (Belopolskii, 1979) and at oceanographic fronts in the Bering Sea (Kinder et al, 1983;Schneider et al, 1990;Coyle et al, 1992;Decker and Hunt, 1996).…”

Section: Discussionmentioning

confidence: 76%

“…Similarly, near Bjørnøya in the Barents Sea, murres (Uria spp.) were seen carrying fish and flying towards the breeding colonies from up to 83 km (45 nautical miles) away (Mehlum et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Hydrographic Features, Cetaceans and the Foraging of Thick-billed Murres snd Other Marine Birds in the Northwestern Barents Sea

Mehlum

Hunt²,

Decker³

et al. 1998

ARCTIC

Self Cite

View full text Add to dashboard Cite

ABSTRACT. The at-sea distribution of thick-billed murres (Uria lomvia) in southeastern Svalbard waters was studied during the summers of 1992, 1993, and 1996. The Storfjordrenna region south of Svalbard was confirmed as an important foraging area for thick-billed murres; murre aggregations were located at distances of 85 to 126 km from the closest breeding colonies. Fish, mainly polar cod (Boreogadus saida), but also capelin (Mallotus villosus), were the main prey found in 16 murres and 3 black-legged kittiwakes (Rissa tridactyla) collected from these aggregations. Murres were seen flying with fish in their beaks at four locations 78 to 102 km away from the colonies. Murre aggregations were associated with frontal zones between cold Arctic waters and warmer Atlantic water, and in areas with strong stratification in salinity at 15 -30 m. A positive association was found between the abundance of murres and the occurrence of cetaceans. Murres and other marine birds were often seen near surfacing cetaceans. The most common cetaceans were minke whales (Balaenoptera acutorostrata) and white-beaked dolphins (Lagenorhynchus albirostris).Key words: marine birds, thick-billed murre, Uria lomvia, foraging ecology, cetaceans, Barents Sea RÉSUMÉ. Durant les étés de 1992, 1993 et 1996, on a étudié la distribution en mer de la marmette de Brünnich (Uria lomvia) dans les eaux du sud-est du Svalbard. La région Storfjordrenna au sud du Svalbard a été confirmée comme une zone importante de collecte pour la marmette de Brünnich; des concentrations de marmettes étaient situées à des distances allant de 85 à 126 km des colonies nicheuses les plus proches. Le poisson, en particulier la morue polaire (Boreogadus saida), mais aussi le capelan (Mallotus villosus), était la proie principale trouvée chez 16 marmettes et 3 mouettes tridactyles (Rissa tridactyla) prélevées dans ces concentrations. On a vu les marmettes voler avec du poisson dans leur bec à quatre endroits éloignés de 78 à 102 km des colonies. Les concentrations de marmettes étaient associées à des zones frontales entre les eaux froides de l'Arctique et l'eau plus chaude de l'Atlantique, et dans des régions ayant une forte stratification dans la salinité à une profondeur de 15 à 30 m. On a trouvé qu'il existait une association positive entre l'abondance des marmettes et la présence des cétacés. On voyait souvent les marmettes et d'autres oiseaux marins près des cétacés qui faisaient surface. Les cétacés les plus communs étaient les petits rorquals (Balaenoptera acutorostrata) et les dauphins à nez blanc (Lagenorhynchus albirostris).Mots clés: oiseaux marins, marmette de Brünnich, Uria lomvia, écologie de collecte, cétacés, mer de Barents Traduit pour la revue Arctic par Nésida Loyer.

show abstract

The importance of the “Polar Front” as a foraging habitat for guillemots Uria spp. breeding at Bjørnøya, Barents Sea

Cited by 18 publications

References 27 publications

Foraging habitat and diving activity of lactating Subantarctic fur seals in relation to sea-surface temperatures at Amsterdam Island

Foraging habitat and diving activity of lactating Subantarctic fur seals in relation to sea-surface temperatures at Amsterdam Island

Scale-dependent predator-prey interactions: the aggregative response of seabirds to prey under variable prey abundance and patchiness

Hydrographic Features, Cetaceans and the Foraging of Thick-billed Murres snd Other Marine Birds in the Northwestern Barents Sea

Contact Info

Product

Resources

About