Local movements and site-tenacity of minke whale in Iceland in relation to feeding and a northward distribution shift

2022 ◽  
pp. 1-18
Author(s):  
Sofia Albrecht ◽  
Jean-Luc Jung ◽  
Laura Lazar ◽  
Marguerite Bathie ◽  
Delphine Lémery-Peissik ◽  
...  
Keyword(s):  
Polar Biology ◽  
2021 ◽  
Author(s):  
Lucas Milmann ◽  
Mioko Taguchi ◽  
Salvatore Siciliano ◽  
Júlio E. Baumgarten ◽  
Larissa R. Oliveira ◽  
...  

1982 ◽  
Vol 60 (8) ◽  
pp. 1806-1811 ◽  
Author(s):  
Roger M. Evans

Black-billed gulls (Larus bulleri) depart form breeding colonies and foraging sites in nonrandom, clumped formations (flocks). Flocks leaving colonies were significantly smaller than those leaving foraging sites, in part owing to more "upflights" at foraging sites. When more birds left a colony per unit time, flocks were both larger and more frequent.A causal model was developed based on the assumptions that flock departures from a colony or foraging site result from the effects of social attractions superimposed on otherwise random departure intervals. This model successfully predicted the size distribution of flocks departing from four colonies and foraging sites. In conjunction with the concepts of site tenacity and habituation, the model also permits a causal explanation of differences in the size of flocks departing colonies compared with foraging sites, and of size differences in flocks arising from "upflights" as opposed to the more common "straggling" columnar formations. The model and results are consistent with the hypothesis that colonies function as assembly points that facilitate group foraging.


Marine Policy ◽  
1998 ◽  
Vol 22 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Trond Bjørndal ◽  
Jon M Conrad
Keyword(s):  

2012 ◽  
Vol 72 (2) ◽  
pp. 235-241 ◽  
Author(s):  
SR Posso ◽  
FB Cintra ◽  
J Frias

The foraging, territoriality and displacement of the Snail Kite were studied over 232 hours of observations in an urban lake during the dry and wet seasons. The temperature and rainfall variations were used to correlate with predation rates and the correlation coefficients were 0,39 and 0,34, respectively. Snail Kites spent more time foraging during the wet than the dry season when perching is more frequently recorded. The higher predation in the wet season can be explained by the higher abundance of apple snails and the energy demand for reproduction. In the wet season, the territories were smaller and the conspecific conflicts decreased as prey were more available. However, due to the lack of food in the dry season, intra-specific conflicts and expansion of male territories were observed and the female and immatures were expelled from their foraging area to another location. In this way, site tenacity of Snail Kites should be interpreted in relation to the variations on food and dominance gradients according to the temporal changes (time) and foraging sites (space).


1996 ◽  
Vol 45 (Suppl. 1) ◽  
pp. 287-287
Author(s):  
MA Olsen ◽  
TH Aagnes ◽  
W. Sørmo ◽  
SD Mathiesen

2020 ◽  
Author(s):  
Yoshihiro Fujise ◽  
Luis A. Pastene

We review the scientific information on whales that could be indicative of historical and current changes in the ecosystem in the Indo-Pacific sector of the Antarctic. The increased krill availability in the middle of the past century as a result of the heavy harvesting of the larger baleen whale species could have been translated into better nutritional conditions for the Antarctic minke whale, resulting in a decreasing trend in the age at sexual maturity and an increasing trend in recruitment rate and hence total population size between approximately 1940 and 1970. This nutritional condition has deteriorated more recently, as revealed by a decrease in energy storage and stomach content weight since the 1980’s; these changes coincide with appreciable increases in the abundances of humpback and fin whales, which were heavily harvested in the first half of the past century. The historical demographic changes observed in the Antarctic minke whale are consistent with the pattern to be expected under the krill surplus hypothesis, with minke whales now again competing with other (recovering) baleen whale species for krill. However, these minke whales could also be using alternative feeding areas (e.g. polynias within the pack-ice) in response to the increase in abundance and geographical expansion of these other large whale species. This could provide an alternative explanation for indications from sighting surveys and population models of a decrease and then re-stabilisation of minke whale abundance in open water areas since the 1970s.


2003 ◽  
Vol 65 (3) ◽  
pp. 423-426 ◽  
Author(s):  
Tetsuya SHIMOKAWA ◽  
Daishiro YAMAGIWA ◽  
Eiichi HONDO ◽  
Shigetoshi NISHIWAKI ◽  
Yasuo KISO ◽  
...  

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