[MARMAM] New paper on North Atlantic killer whales
We are pleased to announce the publication of our paper: Pike, D. G., Gunnlaugsson, T., Mikkelsen, B., Víkingsson, G., & Desportes, G. (2020). Distribution and Abundance of Killer Whales in the Central North Atlantic, 1987-2015. *NAMMCO Scientific Publications*, *11*. https://doi.org/10.7557/3.5579 ABSTRACT: The North Atlantic Sightings Surveys (NASS), covering a large but variable portion of the Central and Eastern North Atlantic, were conducted in 1987, 1989, 1995, 2001, 2007 and 2015. Sightings of killer whales (Orcinus orca), a non-target species, were relatively rare in the Central Atlantic (Icelandic and Faroese) portions of the survey area. In cases where sighting numbers were insufficient, we pooled sightings over several surveys to derive a distance detection function and used this to estimate abundance using standard Distance Sampling methodology. Uncorrected estimates were produced for all surveys, and estimates corrected for perception bias were produced for the 2001 and 2015 surveys. Killer whales were sighted in all areas but were most common in the eastern part of the survey area. Uncorrected abundance in the NASS core area ranged from a low of 4,736 (95% CI: 1,842–12,176) in 1995 to a maximum of 15,142 (95% CI: 6,003–38,190) in 2001. The low precision of the estimates makes the detection of temporal trends unlikely. In 2007 an extension survey revealed relatively high numbers of killer whales to the east of the survey area, in conformity with Norwegian survey estimates in this area. The NASS and other surveys conducted over the period indicate that killer whales number in the low tens of thousands in the Central and Eastern North Atlantic. Regards, Daniel Pike. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
[MARMAM] The Geometer: A new device for recording angles in visual surveys
We are pleased to announce the publication of the following paper: Hansen, R.G., Pike, D., Thorgilsson, B., Gunnlaugsson, T. & Lawson, J. (2020). The Geometer: A New Device for Recording Angles in Visual Surveys. NAMMCO Scientific Publications 11. https://doi.org/10.7557/3.5585 *Abstract:* The Geometer is a new handheld USB device that facilitates a relatively accurate measurement of the declination to a target with instantaneous recording of this and other data. The Geometer offers several advantages over traditional clinometers used in aerial surveys, including easier target pinpointing and tracking, more consistent angle measurements, and integration with software data collection packages. In this note we provide technical specifications for the device and its associated software, and describe a new aerial survey data collection programme that takes full advantage of the features of the Geometer. We have tested this device extensively during aerial surveys and highlight the utility of the hardware as well as ways in which the technology could be improved. Best regards, Daniel Pike. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
[MARMAM] New publication on cetacean numbers and trends around Iceland
We are pleased to announce the publication of our paper: Distribution and abundance of cetaceans in Icelandic waters over 30 years of aerial surveys. The paper is available here: Pike, D. G., Gunnlaugsson, T., Sigurjónsson, J., & Víkingsson, G. A. (2020). Distribution and Abundance of Cetaceans in Icelandic Waters over 30 Years of Aerial Surveys. NAMMCO Scientific Publications 11. https://doi.org/10.7557/3.4805 Best regards, Daniel Pike. ABSTRACT Beginning in 1986, 7 aerial surveys covering the coastal waters of Iceland have been conducted up to and including 2016. In addition, 7 partial surveys covering portions of the same area and at different times of the year have been flown in the same 30-year period. 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. We also examine the distribution of these and other species in Icelandic waters over the 30-year timespan of the surveys, and changes observed over the period. The relative abundance of common minke and humpback whales and white-beaked dolphins was comparatively low in the spring and fall, and peaked in June and July when all of the main surveys have been carried out. An analysis of changes in density as an index of relative abundance from all surveys (1986-2016) indicates that common minke whale abundance decreased by up to 75% after 2001 and has remained at a relatively low level since then. This decrease has been particularly apparent in the southwest and southeast of Iceland, areas which previously had very high densities. Relative abundance of humpback whales and white-beaked dolphins has increased over the period 1986-2016, particularly in the northern part of the survey area. Estimating harbour porpoise abundance and trend was considered unfeasible except from the surveys conducted in 2007 and 2016, which provide abundance estimates of similar magnitude. We place these observed changes in context of oceanographic and ecosystem changes documented over the same period. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
[MARMAM] New paper on cetacean abundance in the Central North Atlantic
We are pleased to announce the publication of the following paper in NAMMCO Scientific Publications: Pike, D.G., Gunnlaugsson, T., Mikkelsen, B., Halldórsson, S.D., Víkingsson, G.A., Acquarone, M. & Desportes, G. (2020). Estimates of the Abundance of Cetaceans in the Central North Atlantic From the T-NASS Icelandic and Faroese Ship Surveys Conducted in 2007. *NAMMCO Scientific Publications *11. https://doi.org/10.7557/3.5269 *ABSTRACT* The Trans-North Atlantic Sightings Survey (T-NASS) carried out in June-July 2007 was the fifth in a series of large-scale cetacean surveys conducted previously in 1987, 1989, 1995 and 2001. The core survey area covered about 1.8 million nm² spanning from the Eastern Barents Sea at 34°E to the east coast of Canada, and between 52°N and 78°N in the east and south to 42°N in the west. We present design-based abundance estimates from the Faroese and Icelandic vessel survey components of T-NASS, as well as results from ancillary vessels that covered adjoining areas. The 4 dedicated survey vessels used a Buckland-Turnock (B-T) mode with a tracker platform searching an area ahead of the primary platform and tracking sightings to provide data for bias correction. Both uncorrected estimates, using the combined non-duplicate sightings from both platforms, and mark-recapture estimates, correcting estimates from the primary platform for bias due to perception and availability, are presented for those species with a sufficient number of sightings. Corrected estimates for the core survey area are as follows: fin whales (*Balaenoptera physalus*): 30,777 (CV=0.19); humpback whales (*Megaptera novaeangliae*): 18,105 (CV=0.43); sperm whales (*Physeter macrocephalus*): 12,268 (CV=0.33); long-finned pilot whales (*Globicephala melas*): 87,417 (CV=0.38); white-beaked dolphins (*Lagenorhynchus albirostris*): 91,277 (CV=0.53); and white-sided dolphins (*L. acutus*): 81,008 (CV=0.54). Uncorrected estimates only were possible for common minke whales (*B. acutorstrata*): 12,427 (CV=0.27); and sei whales (*B. borealis*): 5,159 (CV=0.47). Sighting rates from the ancillary vessels, which used a single platform, were lower than those from the dedicated vessels in areas where they overlapped. No evidence of responsive movement by any species was detected, but there was some indication that distance measurements by the primary platform may have been negatively biased. The significance of this for the abundance estimates is discussed. The relative merits of B-T over other survey modes are discussed and recommendations for future surveys provided. The paper is available for download here: https://septentrio.uit.no/index.php/NAMMCOSP/article/view/5269 Best regards, Daniel Pike. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
[MARMAM] Three more new papers on North Atlantic whales
, Icelandic, Spanish, Greenlandic and Faroese vessels and aircraft (coordinated by NAMMCO through its Scientific Committee from 1995), and surveys under the US’s Marine Mammal Protection Act and the European Union’s Small Cetacean Abundance in the North Sea (SCANS) programme. Fishery independent cetacean sighting surveys have proven to be both central and essential to understanding and regulating of human impacts on cetaceans. Regards, Daniel Pike. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
[MARMAM] New papers on North Atlantic whale abundance
Hello I would like to announce the recent publication of the following 3 papers in *NAMMCO Scientific Publications* Volume 7, North Atlantic Sightings Surveys: Counting whales in the North Atlantic, 1987-2001. The volume is available at www.nammco.no, and pdf reprints are available from me at kin...@gmail.com. Regards, Daniel Pike. Pike, D.G., Víkingsson, G.A., Gunnlaugsson, Th. and Øien, N. 2009. A note on the distribution and abundance of blue whales (*Balaenoptera musculus*) in the Central and Northeast North Atlantic. *NAMMCO Sci. Publ*. 7:19-29. The distribution and abundance of blue whales (*Balaenoptera musculus*) was assessed from ship surveys conducted in the Central and Northeast Atlantic in 1987, 1989, 1995 and 2001. Blue whales were most commonly sighted off western Iceland, and to a lesser extent northeast of Iceland. They were very rare or absent in the Northeast Atlantic. Sightings were combined over all surveys to estimate the detection function using standard line transect methodology, with the addition of a covariate to account for differences between surveys. Total abundance was highest in 1995 (979, 95% CI 137-2,542)and lowest in 1987 (222, 95% CI 115-440). Uncertainty in species identity had little effect on estimates of abundance. There was a significant positive trend in abundance northeast of Iceland and in the total survey area. Pike, D.G., Gunnlaugsson, Th., Víkingsson, G.A., Desportes, G. and Bloch, D. 2009. Estimates of the abundance of minke whales (*Balaenoptera acutorostrata*) from Faroese and Icelandic NASS shipboard surveys. *NAMMCO Sci. Publ*. 7:81-93. North Atlantic Sightings Surveys for cetaceans were carried out Northeast and Central Atlantic in 1987, 1989, 1995 and 2001. Here we provide estimates of density and abundance for minke whales from the Faroese and Icelandic ship surveys. The estimates are not corrected for availability or perception biases. Double platform data collected in 2001 indicates that perception bias is likely considerable for this species. However comparison of corrected estimates of density from aerial surveys with a ship survey estimate from the same area suggests that ship surveys can be nearly unbiased under optimal survey conditions with high searching effort. There were some regional changes in density over the period but no overall changes in density and abundance. Given the recent catch history for minke whales in this area, we would not expect to see changes in abundance due to exploitation that would be detectable with these surveys. Pike, D.G., Paxton, C.G.M., Gunnlaugsson, Th. and Víkingsson, G.A. 2009. Trends in the distribution and abundance of cetaceans from aerial surveys in Icelandic coastal waters, 1986-2001. NAMMCO Sci. Publ. 7:117-142. Aerial surveys were carried out in coastal Icelandic waters 4 times between 1986 and 2001 as part of the North Atlantic Sightings Surveys. The surveys had nearly identical designs in 3 of the 4 years. The target species was the minke whale (*Balaenoptera acutorostrata*) but all species encountered were recorded. Sighting rate and density from line transect analysis were used as indices of relative abundance to monitor trends over the period, and abundance estimates corrected for perception biases were calculated for some species from the 2001 survey. More than 11 species were sighted, of which the most common were the minke whale, humpback whale (*Megaptera novaeangliae*), dolphins of genus *Lagenorhychus*, and the harbour porpoise (*Phocoena phocoena*). Minke whales and dolphins showed little change in distribution or abundance over the period. There were an estimated 31,653 (cv 0.30) dolphins in the survey area in 2001. Humpback whales increased rapidly at a rate of about 12%, with much of the increase occurring off eastern and northeastern Iceland. In 2001 there were an estimated 4,928 (cv 0.463) humpback whales in the survey area. The relative abundance of harbour porpoises decreased over the period, but estimates for this species were compromised by uncorrected perception biases and poor coverage. The ecological and historical significance of these findings with respect to previous whaling activities and present-day fisheries is discussed. ___ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
