Zoeken
Zoeken kan via de modus 'eenvoudig zoeken' (één veld) of uitgebreid via 'geavanceerd zoeken' (meerdere velden). Zo kan je bv. zoeken op een combinatie van een auteursnaam (auteur), een jaartal (jaar) en een documenttype.
Boekenmand
Nuttige resultaten kan je aanvinken en toevoegen aan een mandje. De inhoud hiervan kan je exporteren of afdrukken (naar bv. PDF).
RSS
Op de hoogte blijven van nieuw toegevoegde publicaties binnen uw interessegebied? Dit kan door een RSS-feed (?) te maken van jouw zoekopdracht.
nieuwe zoekopdracht
Coastal distribution, movements and site fidelity of right whales Eubalaena australis off South Africa, 1969-1998
Best, P.B. (2000). Coastal distribution, movements and site fidelity of right whales Eubalaena australis off South Africa, 1969-1998. S. Afr. J. Mar. Sci./S.-Afr. Tydskr. Seewet. 22: 43-55
In: South African Journal of Marine Science = Suid-Afrikaanse Tydskrif vir Seewetenskap. Marine & Coastal Management: Cape Town. ISSN 0257-7615
|  |
| Abstract |
Counts and photographs of right whales Eubalaena australis taken on aerial surveys of the southern coast of South Africa between 1969 and 1998 have been used to examine patterns of coastal distribution between successive 20-minute bins of longitude. Some bins had consistently higher densities of whales than others, either of cows with carves or of unaccompanied adults. Apart from an overall increase in density, the centre of distribution shifted 40-60 minutes of longitude to the west over the 30-year period. Most (< 93.4%) female calves born on the South African coast returned there to have their first calf, but only 52.9% were photographed with their first calf in the same or an adjacent bin as that of their natal year. This compares with 60.9% of multigravid females that occurred in the same or an adjacent bin as that of their; previous calf, with significantly more westward (368) than eastward (255) shifts in distribution between calves. Approximate residence times for cow-calf pairs in the De Hoop region were 12-105 (average = 59.0 +/- 3.9) days: dispersal rates were low between July and September but increased thereafter. Incidental records of coastwise movement were mainly to the west, but were probably influenced by the survey direction. Distances moved ranged from 6 to 202 km. at average speeds of 0.08-2.89 km.h(-1). Theodolite tracking of undisturbed groups of right whales from Cape Columbine produced a similar range of swimming speeds. Inter-calf movements of cows between the survey area and the coasts to both east and west indicated that the entire South African coast could be considered as one homogeneous winter assemblage area for right whales. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
