Heike Vester

Genetic differentiation among North Atlantic killer whale populations

Population genetic structure of North Atlantic killer whale samples was resolved from differences in allele frequencies of 17 microsatellite loci, mtDNA control region haplotype frequencies and for a subset of samples, using complete mitogenome sequences. Three significantly differentiated populations were identified. Differentiation based on microsatellite allele frequencies was greater between the two allopatric populations than between the two pairs of partially sympatric populations. Spatial clustering of individuals within each of these populations overlaps with the distribution of particular prey resources: herring, mackerel and tuna, which each population has been seen predating. Phylogenetic analyses using complete mitogenomes suggested two populations could have resulted from single founding events and subsequent matrilineal expansion. The third population, which was sampled at lower latitudes and lower density, consisted of maternal lineages from three highly divergent clades. Pairwise population differentiation was greater for estimates based on mtDNA control region haplotype frequencies than for estimates based on microsatellite allele frequencies, and there were no mitogenome haplotypes shared among populations. This suggests low or no female migration and that gene flow was primarily male mediated when populations spatially and temporally overlap. These results demonstrate that genetic differentiation can arise through resource specialization in the absence of physical barriers to gene flow.

Click sounds produced by cod (Gadus morhua)

Conspicuous sonic click sounds were recorded in the presence of cod (Gadus morhua), together with either harp seals (Pagophilus groenlandicus), hooded seals (Cystophora cristata) or a human diver in a pool. Similar sounds were never recorded in the presence of salmon (Salmo salar) together with either seal species, or from either seal or fish species when kept separately in the pool. It is concluded that cod was the source of these sounds and that the clicks were produced only when cod were approached by a swimming predatorlike body. The analyzed click sounds (n = 377) had the following characteristics (overall averages +/- S.D.): peak frequency = 5.95 +/- 2.22 kHz; peak-to-peak duration = 0.70 +/- 0.45 ms; sound pressure level (received level) = 153.2 +/- 7.0 dB re 1 microPa at 1 m. At present the mechanism and purpose of these clicks is not known. However, the circumstances under which they were recorded and some observations on the behavior of the seals both suggest that the clicks could have a predator startling function.

Call for cooperation to contain damage by Chile's salmon farms

The proposed Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (Nature 465, 525; 2010) should be part of a broader complementary system of scientific input. This would help to coordinate data that fall under the remit of multiple international environmental agencies and agreements. And it would minimize the risks of duplication in scientific review and reporting. A global consultation of scientists and others, coordinated by DesertNet International and the United Nations Institute for Water, Environment and Health (www.desertnet-international. org), has suggested that an equivalent intergovernmental science-policy panel for land and water issues is needed. Otherwise, important independent questions are likely to be absorbed by the scientific bodies that advise on climate change and biodiversity loss. Crucial matters may not receive the policy attention they deserve if solely addressed by the Intergovernmental Panel on Climate Change and the proposed IPBES. Examples are the impacts of trends in population growth and demographic bulges; food and energy insecurity; migration; and ‘land and water grabbing’ by wealthy foreign companies in developing nations. Lindsay C. Stringer School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK e-mail: l.stringer@leeds.ac.uk Call for cooperation to contain damage by Chile’s salmon farms

Southernmost Distribution of Common Bottlenose Dolphins (Tursiops truncatus) in the Eastern South Pacific

The common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan species that does not range to latitudes greater than 45o in either hemisphere, with a few exceptions. In South American waters, this species is generally distributed in the Atlantic Ocean south to Chubut province (ca. 46o S), while in the eastern South Pacific this species has been recorded in northern and central Chile, with a few records south to 40o S. Here we summarize recent records of common bottlenose dolphins obtained during systematic marine mammal surveys in the Chilean Patagonian and Fuegian channels and fjords (the Los Lagos, Aysén, and Magallanes regions of Chile). These data suggest an extension of the documented range of the species southwards, indicating that bottlenose dolphins may have colonized new areas in the eastern South Pacific or as the result of an increase in survey efforts by scientists in the region.

Quantifying group specificity of animal vocalizations without specific sender information.

Recordings of animal vocalization can lack information about sender and context. This is often the case in studies on marine mammals or in the increasing number of automated bioacoustics monitorings. Here, we develop a framework to estimate group specificity without specific sender information. We introduce and apply a bag-of-calls-and-coefficients approach (BOCCA) to study ensembles of cepstral coefficients calculated from vocalization signals recorded from a given animal group. Comparing distributions of such ensembles of coefficients by computing relative entropies reveals group specific differences. Applying the BOCCA to ensembles of calls recorded from group of long-finned pilot whales in northern Norway, we find that differences of vocalizations within social groups of pilot whales (Globicephala melas) are significantly lower than intergroup differences.

First record of killer whales (Orcinus orca) feeding on Atlantic salmon (Salmo salar) in northern Norway suggest a multi-prey feeding type

Killer whales (Orcinus orca) are widely distributed throughout the world’s oceans, where they forage on a large variety of different prey species ranging from fish to marine mammals and birds (Forney & Wade, 2007). It has been shown that feeding ecology is of central importance to the killer whales’ social network. Food availability has a direct influence on group structure, and it is under debate to what extent the sociality of killer whales is flexible enough to adapt to local ecological conditions (Beck et al., 2012; Foster et al., 2012). In the north-east Pacific some highly specialized sympatric populations have evolved, with resident groups foraging on salmonids, transient groups feeding on marine mammals, and offshore groups feeding on fish such as sharks (Ford et al., 1998). Often these specialized populations show high site and time fidelity, such as the northern and southern resident lines in the north-east Pacific which feed primarily on Chinook salmon (Oncorhynchus tshawytscha) (Ford & Ellis, 2006). The survival of these killer whales seems to depend on the Chinook salmon’s year-round abundance (Ford et al., 2010). In the north-east Atlantic at least two different populations have been recently identified, including a herring feeding population in Norway and Iceland (Foote et al., 2011). In addition, two ecotypes of North Atlantic killer whales with morphological differences were determined: Type 1, with severe apical tooth wear, a generalist type with a length of up to 6.6 m, presumably feeding on fish and to some extent on seals; and Type 2, with no apical tooth wear, a highly specialized type with a length of up to 8.5 m, presumably feeding on other whales (Foote et al., 2009). Further, marine mammal–feeding killer whales were described from Scottish inshore waters (Bolt et al., 2009). In Irish waters, killer whales mostly feed on fish; stomach contents revealed a diet of siphonostomatoid copepods (Cecrops latreilli), ocean sunfish (Mola mola), mullet (Chelon labrosus) and salmon (Salmo salar) (Ryan & Wilson, 2003; McHugh et al., 2007, Ryan & Holmes, 2012), and in the 1970s a killer whale was observed hunting salmon in the Lough Foyle Estuary (Wilson & Pitcher, 1979). In the waters around the British Isles, herring and salmon were identified as prey species (Evans, 1988). Thus, we are only starting to understand the variety of the North Atlantic killer whales’ feeding ecology, especially the degree of prey specializations. Killer whales studied in Norway feed mostly on herring, with tagged animals showing high site and time fidelity to Fig. 1. Salmon caught by killer whale in Oksfjord, northern Norway, 2011. Photograph kindly provided by Geir Notnes.

Whale watching in Norway caught between more traditional hunting canons and the lucrative promise of seismic airguns.

This research note concerns the role of whale-watching tourism providers in the debate over protection of the marine environment. The case reported is about northern Norwegian whale-watching organizations. Based on the analysis of local newspapers and on the direct experience of one member of our research team, this research note concludes that the whale-watching companies, and more in general the wildlife tourism companies, engage only marginally in the debate. This can be explained referring to the companies’ limited availability of resources and experience in the field, and to the existence of different perspectives relative to the way humans can use and impact the marine environment and its inhabitants.

Vocal repertoire of long-finned pilot whales (Globicephala melas) in northern Norway

The knowledge of the vocal repertoire of pilot whales is very limited. In this paper, the vocal repertoire of long-finned pilot whales recorded during different encounters in the Vestfjord in northern Norway between November 2006 and August 2010 are described. Sounds were analysed using two different methods: (1) an observer-based audio-visual inspection of FFT-derived spectrograms, with which, besides a general variety of clicks, buzzes, nonharmonic sounds, and whistles, 129 different distinct call types and 25 subtypes were distinguished. These call types included pulsed calls and discrete structured whistles varying from simple to highly complex structures composed of several segments and elements. In addition, ultrasonic whistles previously not described for pilot whales were found. In addition to the diversity of single calls, call sequences consisting of repetitions and combinations of specific call types were recorded and (2) a parametric approach that permitted the confirmation of the high variability in pilot whale call structures was developed. It is concluded that the pilot whale vocal repertoire is among the most complex for the mammalian species and the high structural variability, along with call repetitions and combinations, require a closer investigation to judge their importance for vocal communication.