Thesis (M.E.S.)--Evergreen State College, 2009. / "June 2009." Title from title screen (viewed 4/8/2010). Includes bibliographical references (p. 41-48).

Underwater vocalizations were recorded from pods of wild killer whales (Oreinus orca) off Vancouver Island, British Columbia, during 1978-83. Acoustic exchanges within pods are dominated by repetitious, pulsed calls which can be organized into discrete categories. Repeated encounters with 16 photographically-identified 'resident' pods demonstrate that each pod produces a repertoire of 7 to 17 (mean = 10.7) discrete call types. Recordings of captive whales of known pod origin and historical field recordings indicate that pod repertoires remain stable for periods of at least 18 years (1965-83) and possibly 25 years (1958-83). Each individual whale appears capable of producing most or all of the calls in it's pod's repertoire. Repertoires are apparently learned. All discrete call types tend to be used in all 'active' contexts, which consist mainly of foraging and travelling. Few call types are clearly correlated with specific behaviours. Activities involving tight group formation and physical interaction among pod members were accompanied by an increase in the use of whistles and variable pulsed sounds. Significant differences exist among the call repertoires of different pods. The 16 resident pods on the B.C. coast can be arranged into 4 acoustic associations, each of which has a unique set of discrete call types. These associations are referred to as 'call traditions', and the pods belonging to a tradition form a 'clan'. Pods within each clan share some call types, but may also produce unique calls. Shared calls often have different pod-specific renditions. These differences form a system of related dialects within each call tradition. Three of the four resident clans belong to a single community, and pods from these clans frequently associate with one another. Observed patterns of association were often unrelated to acoustic relationships. The fourth resident clan forms a community with a separate range. A community of 17 'transient' pods is sympatric with but socially isolated from the resident communities. This community has a wide range, and appears to consist of a single call tradition. The call traditions and dialects described here are apparently unique among mammals. Various hypotheses to account for their origin and adaptive significance are discussed. Clans could represent independent lineages which arrived on the B.C. coast through a series of unrelated founding events. As the founding pod of each clan grew and divided, its group-specific call repertoire diverged, either through functionless cultural drift or by an active process promoting acoustic differentiation of related groups. Dialects may have no selective value, or they may serve as kin-recognition signals for maintaining pod cohesion and identity or avoiding excessive inbreeding. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 87-95).

Thesis (M.Sc.(Zoology and Entomology))--University of Pretoria, 2008. / The thesis is structured as three separate papers to be submitted to journals for publication, with a single reference list at the end. Includes bibliographical references (leaves 130-147).

Field observations were collected to assess the social behaviour and foraging strategies of free-ranging killer whales from the eastern North Pacific (near Vancouver Island, Canada) and the western South Atlantic (near Peninsula Valdez, Argentina). The Vancouver Island study concentrated on the environmental correlates of group size and the behavioural dynamics of social groups. There were no correlations between foraging behaviour and small-scale habitat use, however both group size and the spatial distribution of groups were correlated with foraging behaviour. In Argentina the subject whales intentionally stranded to capture pup sea lions. It was possible to observe details of prey choice and foraging strategy. Three social groups were observed in the study area. Area use suggested that the different groups were employing different strategies. Whales within social groups shared prey, but one group would exclude another from the best hunting areas. Whales invested the greatest effort in the area of highest yield, and on the prey-type that required the least effort to catch. Energetic calculations suggested that the rate at which these whales captured sea lion prey was just sufficient to sustain them. Two genetic components, the hypervariable 'minisatellite' loci, and the mitochondrial genome were investigated for each study population. In addition, further samples from Iceland and other populations near the sites at Peninsula Valdez and Vancouver Island were analysed. Whales within social groups at Peninsula Valdez were more closely related than between social groups. In general, whales within local populations had very high levels of genetic similarity compared to between population comparisons. This implies inbreeding within and genetic isolation between populations. Two genetically isolated populations (both near Vancouver Island) were sympatric, and the degree of genetic isolation was equal to the level seen for comparisons between the Atlantic and Pacific. A hypothesis is presented on the role of resource exploitation in the structuring of social groups, and the consequences for the genetic structuring of populations.

In this thesis I take a multi-disciplinary approach to identify and characterise ‘Evolutionary Significant Units’ (ESUs) and ‘Management Units’ (MUs) of killer whale in the eastern North Atlantic. Several markers and traits including mitochondrial DNA control region, 15N stable isotope values, tooth wear, tooth count, total body length and pigmentation pattern indicated sympatric lineages could be categorized in to two ecologically & morphologically disparate types, which should be considered as distinct ESUs. One type (type 2) appears to be a specialist and may predate cetaceans. The other type (type 1) appears to be a generalist, although the total niche width of the population appears to be more dependent upon between-individual variation than within-individual variation in dietary composition. However, the other indicator of long-term diet, apical tooth wear, was found in all type 1 individuals, suggesting some overlap in the components of the diet. There are shallow genetic differences between the two types based on mtDNA control region, however analysis of bi-parentally inherited nuclear DNA markers are needed to see if the two types are reproductively isolated. The data above on diet is further supported by observational data of individuals moving between the Icelandic herring grounds to the seal pupping haul-outs around the Northern Isles, Scotland. However, large scale movement of individuals is mostly correlated with the movement of large predictable prey stocks such as the Icelandic and Norwegian stocks of Atlantic herring. Therefore there is the potential for prey choice to cause intrinsic isolation through temporal or spatial isolation even when the prey type is similar, e.g. mackerel, Icelandic herring or Norwegian herring. The microsatellite data are consistent with this pattern and taken together the genetic and mark-recapture data identify four demographically independent MUs of type 1 killer whales. We only identify one community or MU of type 2 killer whales, which is small (10 individuals) and appears to be suffering from demographic stochasticity. Our results suggest intrinsic isolation through temporal and spatial isolation as the most parsimonious mechanism for reducing gene flow between populations of the same type. Further work is needed to determine if there is gene flow between types or if adaptive divergence feeds back to reduce gene flow through mate choice.

Resident killer whales (Orcinus orca) in the Salish Sea use echolocation clicks to hunt for Chinook salmon, their preferred prey. An increase in underwater anthro- pogenic noise in recent decades has been identified as a threat to their survival due to auditory masking effects on these signals. Studies quantifying the effects of anthro- pogenic noise on echolocation signals have yet to be carried out due to a data gap for echolocation acoustic characteristics. In particular, to date, only one study has reported click characteristics for northern resident killer whales, and no results have been reported for southern residents. This thesis reports on acoustic recordings of resident killer whale echolocation clicks gathered over two summers in several loca- tions around Vancouver Island, and spectral and temporal characteristics extracted from them. Acoustic characteristics are reported separately for southern and north- ern resident killer whales based on 708 clicks from 19 click trains and 1277 clicks from 16 click trains, respectively. Results are further categorized into click type (slow, fast, and buzz clicks) based on inter-click interval, an indicator of foraging phase. Results show no differences in acoustic characteristics between the northern and southern killer whales, suggesting echolocation clicks do not vary between these subspecies. No significant differences are noted between slow- and fast-click characteristics, while buzz clicks appear to have some significant differences in characteristics from the oth- ers. Apparent source level values for northern and southern killer whales vary between 179-221 dB re 1 μPa at 1 m and 192-220 dB re 1 μPa at 1 m, respectively, based on the largest amplitude click from each click train (assumed to be directed towards the recording array). The values reported in this thesis will be used in subsequent noise modelling studies to quantify the effects of anthropogenic noise on resident killer whale ability to hunt for prey via echolocation signals. / Graduate

Thesis (M.S.)--University of British Columbia, 1996. / Includes bibliographical references (p. 51-61). Also available in electronic format via Internet.

Sightings and acoustic recordings from 1984 to 1989 of northern resident killer whales (Orcinus orca) from Johnstone Strait off north eastern Vancouver Island and from King Island on the central British Columbia coast were analysed to examine the hypothesis that northern resident whales move seasonally in their range to areas where salmon are available. Killer whales were most abundant in Johnstone Strait between July and October and infrequent during the remainder of the year. The increase in whale abundance during summer coincided with the migration of salmon (Oncorhynchus spp.) from offshore into Johnstone Strait. The occurrence near King Island in spring 1989 of the same resident whales that are seen in Johnstone Strait during summer, coincided with runs of sockeye and chinook salmon. During July, August and September of 1984 through 1988, killer whale sightings were recorded virtually daily in the Johnstone Strait. Observations of killer whales in Johnstone Strait during the summer of 1988 showed that whales foraged along shore and in areas of strong current where salmon occur in high densities. Of the 16 killer whale pods in the northern resident community, however, less than half were present more than 15% of summer days (1984 to 1988). Regression results between numbers of whale days per week from each pod and numbers of salmon per week showed that the occurrence pods that were present on more than 15% of summer days in Johnstone Strait was positively and significantly associated with the abundance of sockeye and pink salmon (six pods). In addition to these, the occurrence of one pod that spent less than 15% of summer days in the Strait was positively and significantly associated with chum salmon. Together these results support the hypothesis that northern resident killer whales select their habitat seasonally to feed on available salmon. The results also lead to the hypothesis that within the northern resident community each pod has a seasonal home ranges. / Land and Food Systems, Faculty of / Graduate

Killer whales inhabiting coastal waters of the northeastern Pacific are listed under the Canadian Species at Risk Act, which requires the identification of critical habitats for the recovery of their populations. Little is known about their distribution during the winter and what areas are important for their survival during these months. Passive acoustic monitoring is a valuable complementary method to traditional visual and photographic surveys although it has seldom been used to study killer whales and there are limitations in practice. There is a need to develop tools and protocols to maximize the efficiency of such studies. In this thesis, long-term acoustic data collected with autonomous recorders were analyzed 1) to assess the performance of two types of analysis (Manual and Long Term Spectral Averages) for detecting and identifying killer whale calls and to compare the effects of using two different duty cycles (1/3 and 2/3); and 2) to investigate the seasonal occurrence of different killer whale populations at two sites off the west coasts of Vancouver Island and Washington: Swiftsure Bank and Cape Elizabeth. Both the use of Long Term Spectral Averages and a lower duty cycle resulted in a decrease in call detection and resolution of call identification, leading to underestimations of the amount of time the whales spent at the site. A compromise between a lower resolution data processing method and a higher duty cycle (and vice-versa) is therefore suggested for future passive acoustic monitoring studies of killer whales. Killer whale calls were detected on 186 days at Swiftsure Bank and on 39 days at Cape Elizabeth. The seasonal occurrence of killer whales at Swiftsure Bank highlights its importance as a killer whale hotspot, with year-round presence of Southern Residents and British Columbia Transients, Northern Residents in spring and fall, and California Transients on rare occasions. These results support the expansion of Southern Resident’s critical habitat to include Swiftsure Bank. Temporal habitat partitioning between Resident populations was observed at Cape Elizabeth, with Southern Residents detected from January through June and Northern Residents from July to September. These results show that Northern Residents use the southern parts of their range more frequently than previously thought. Both Transient populations were frequently detected throughout the year, suggesting habitat overlapping. / Graduate