Abstract
Beginning in 1986, 7 aerial surveys covering the coastal waters of Iceland have been conducted up to 2016. In addition, several partial surveys covering portions of the same area and at different times of the year have been flown in the same 30 year time span. We present previously unpublished abundance estimates, corrected to the extent feasible for known biases, for common minke whales (Balaenoptera acutorostrata), humpback whales (Megaptera novaeangliae), white-beaked dolphins (Lagenorhynchus albirostris) and harbour porpoises (Phocoena phocoena) from some or all of the 2007, 2009 and 2016 surveys. The relative abundance of most species was comparatively low in the spring and fall, and peaked June and July when all of the main surveys have been carried out. An analysis of changes in line transect density as an index of relative abundance from all surveys indicates that common minke whale abundance decreased by 75% after 2001 and has remained at a relatively low level since then. Relative abundance of humpback whales and white-beaked dolphins has increased over the period 1986-2016. We place these observed changes in context with oceanographic and ecosystem changes documented over the same period.
Highlights
The first full-scale aerial survey for cetaceans covering the Icelandic shelf and territorial waters during late June-July was carried out in 1986 and the most recent one, covering nearly the same survey area, was completed in 2016
In some cases corrected for bias due to visible whales missed by observers, have been provided for humpback whales (1995, 2001) (Paxton et al, 2009; Pike, Paxton, Gunnlaugsson, & Víkingsson, 2009), white-beaked dolphins (Lagenorhynchus albirostris) (1986, 1995, 2001) and harbour porpoises (1986, 1995) (Pike et al, 2009)
We provide fully corrected cue-count estimates of common minke whale abundance from the 2007, 2009 and 2016 surveys, as well as line transect estimates from surveys where sufficient sightings were realized and corrected for perception bias for humpback whales (2007, 2009), whitebeaked dolphins (2007, 2009, 2016) and harbour porpoises (2016)
Summary
The first full-scale aerial survey for cetaceans covering the Icelandic shelf and territorial waters during late June-July was carried out in 1986 and the most recent one, covering nearly the same survey area, was completed in 2016. Over this 30-year period, complete surveys have been attempted 7 times, usually as a component of the North Atlantic Sightings Surveys (NASS), in 1986, 1987 (incompletely), 1995, 2001, 2007, 2009, 2015 (incompletely) and 2016. Gilles et al (under revision) provide a fully-corrected estimate of harbour porpoise abundance from the 2007 survey
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
