[MARMAM] New publication: Abundance of whales in West and East Greenland in summer 2015
solveig.enoksen at nammco.no
Wed Mar 27 01:22:43 PDT 2019
Dear MARMAM members,
The North Atlantic Marine Mammal Commission is pleased to announce the early online publication of the second article of Volume 11 in our Scientific Publication Series, "Abundance of whales in West and East Greenland in summer 2015" by Rikke G. Hansen, Tenna K. Boye, Rasmus S. Larsen, Nynne H. Nielsen, Outi Tervo, Rasmus D. Nielsen, Marianne H. Rasmussen, Mikkel H. S. Sinding and Mads Peter Heide-Jørgensen.
An aerial line transect survey of whales in West and East Greenland was conducted in August-September 2015. The survey covered the area between the coast of West Greenland and offshore (up to 100 km) to the shelf break. In East Greenland, the survey lines covered the area from the coast up to 50 km offshore crossing the shelf break. A total of 423 sightings of 12 cetacean species were obtained and abundance estimates were developed for common minke whale, (Balaenoptera acutorostrata) (32 sightings), fin whale (Balaenoptera physalus) (129 sightings), humpback whale (Megaptera novaeangliae) (84 sightings), harbour porpoise (Phocoena phocoena) (55 sightings), long-finned pilot whale, (Globicephala melas) (42 sightings) and white-beaked dolphin (Lagenorhynchus albirostri) (50 sightings). The developed at-surface abundance estimates were corrected for both perception bias and availability bias if possible. Data on surface corrections for minke whales and harbour porpoises were collected from whales instrumented with satellite-linked time-depth-recorders. Options for estimation methods are presented and the preferred estimates are: minke whales: 5,095 (95% CI: 2,171-11,961) in West Greenland and 2,762 (95% CI: 1,160-6,574) in East Greenland, fin whales: 2,215 (95% CI: 1,017-4,823) in West Greenland and 6,440 (95% CI: 3,901-10,632) in East Greenland, humpback whales: 993 (95% CI: 434-2,272) in West Greenland and 4,223 (95% CI: 1,845-9,666) in East Greenland, harbour porpoises: 83,321 (95% CI: 43,377-160,047) in West Greenland and 1,642 (95% CI: 319-8,464) in East Greenland, pilot whales: 9,190 (95% CI: 3,635-23,234) in West Greenland and 258 (95% CI: 50-1,354) in East Greenland, white-beaked dolphins 15,261 (95% CI: 7,048-33,046) in West Greenland and 11,889 (95% CI: 4,710-30,008) in East Greenland. The abundance of cetaceans in coastal areas of East Greenland has not been estimated before, but the limited historical information from the area indicates that the achieved abundance estimates were remarkably high. When comparing the abundance estimates from 2015 in West Greenland with a similar survey conducted in 2007, there is a clear trend towards lower densities in 2015 for the three baleen whale species and white-beaked dolphins. Harbour porpoises and pilot whales, however, did not show a similar decline. The decline in baleen whale and white-beaked dolphin abundance is likely due to emigration to the East Greenland shelf areas where recent climate driven changes in pelagic productivity may have accelerated favourable conditions for these species.
The article is open access and available here: https://doi.org/10.7557/3.4689
Volume 11: North Atlantic Sightings Surveys - Counting whales in the North Atlantic 2002-2016 will consist of a series of articles dealing with the results of NASS, a series of internationally coordinated cetacean surveys that were conducted in the North Atlantic in 1987, 1989, 1995, 2001, 2007 and 2015.
Editorial Assistant, NAMMCO Scientific Publications Series
Scientific & Communication Assistant
NAMMCO - North Atlantic Marine Mammal Commission
POB 6453, N-9294 Tromsø, Norway
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