|Harbour porpoise (Phocoena phocoena) densities obtained from aerial surveys north of Fyn and nin the Bay of Kiel|
Heide-Jørgensen, M.P.; Mosbech, A.; Teilmann, J.; Benke, H.; Schultz, W. (1992). Harbour porpoise (Phocoena phocoena) densities obtained from aerial surveys north of Fyn and nin the Bay of Kiel. Ophelia 35(2): 133-146
In: Ophelia: International Journal of Marine Biology. Ophelia Publications: Helsingør. ISSN 0078-5326, more
Aerial surveys; Marine mammals; Population density; Phocoena phocoena (Linnaeus, 1758) [WoRMS]; Denmark [Marine Regions]; Marine
|Authors|| || Top |
- Heide-Jørgensen, M.P.
- Mosbech, A.
- Teilmann, J.
Aerial surveys covering 5117 linear kilometers were conducted at 91 and 183 m altitude under optimal sighting conditions in an area north of Fyn, Denmark, and in the Bay of Kiel, Germany, in June-July 1991. A total of 116 harbour porpoise, Phocoena phocoena , pods (140 animals) were observed, of which 22 were seen in the Bay of Kiel. The mean of the pod sizes ranged between 1.1 and 1.3, and they were used to estimate the actual number of porpoises present at surface during the survey. The abundance of porpoises in the area north of Fyn was 457 (95% CI: 288-726) which was significantly larger than the estimate of 160 for the Bay of Kiel (95% CI: 96-267). The mean pod size was lower than estimates obtained from shipboard surveys. A more realistic and independent estimate of mean pod size (1.96) was used to calculate abundances of 820 (95% CI: 519-1297) and 251 (95% CI: 153-410) porpoises in the area north of Fyn and the Bay of Kiel, respectively.