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CETACEANS

In addition to our work over the last four decades on the Southern resident killer whales we have also carried out studies of other populations and recorded all cetaceans that we have encountered during our surveys. Both through our own research and the research of others this data has been used to examine broad scale changes in the population dynamics of other cetaceans.

Transient (Bigg’s) killer whales (Orcinus orca)
Humpback whales
(Megaptera novaeangliae)
Blue Whales
(Balaenoptera musculus)
Bottlenose dolphins
(Tursiops truncates)

Transient (Bigg’s) killer whales (Orcinus orca)

Transient killer whales are sympatric with the Southern resident killer whales and we have been documenting their occupancy in the Salish Sea over the last four decades. Using the same methods that we have used for data collection on the Southern resident killer whales we have taken annual photographic censuses and recorded their spatial, social and foraging behaviour. Our transient killer whale data set now consists of hundreds of individuals that have been documented by 1000s of photographs. We are currently using this long-term data to examine patterns of social behaviour and space use in this population and our long term monitoring has shown that the occupancy of transient killer whales in the Salish Sea has increased over the last decade (?) (REF) . We have observed numerous kills by transient killer whales, which in contrast to resident killer whales, feed on marine mammals (typically small cetaceans and pinnipeds). Our observations have shown that transient killer whales will occasionally kill larger cetaceans such as minke whales (Balaenoptera acutorostrata) and that they do this by repeatedly ramming or by asphyxiating their prey (Ford et al. 2005).

 

 

 

Humpback whales (Megaptera novaeangliae)

Over the last four decades we have assembled a photographic database of humpback whales that we have encountered on our surveys. This data set contains over XX individuals that form part of a large population that range from Washington down to Central America. Our photographs of known individuals have contributed to collaborative studies to estimate the size of this population (Calambokidis et al. 1990a; Urban et al. 1999) and to study its structure and migration patterns (Calambokidis et al. 1996; Darling et al. 1996; Calambokidis et al. 2000; Calambokidis et al. 2001). This work has shown that humpback whales seen off California, Oregon and Washington show a high degree of interchange and form a single intermixed and feeding aggregation with limited interchange with areas further north (Calambokidis et al. 1996). Our observations have helped to confirm that animals that feed off North California and Washington over the summer, move to the tropical waters off Mexico during the winter (Calambokidis et al. 2000) and that some humpback whales that spend their summer off British Columbia migrate to Japan during the winter months (Darling et al. 1996).

 

 

 

Blue Whales (Balaenoptera musculus)

The global population of blue whales was greatly depleted by commercial whaling with estimates suggesting that at least 70% and possibly as much as 90% of the population had been depleted (Reilly et al. 2008). There are uncertainties over the actual abundance of blue whales and our photo identifications of blue whales has helped to establish the population size and movement patterns of whales living off the west coast of North and Central America. Our work has helped to demonstrate that the number of blue whales increased off the coast of central California over a relatively short time period (3 years) with about 3% of individuals been repeatedly sighted annually over a 3 year period (Calambokidis et al. 1990b). Individuals sighted off the coast of California were also seen off west coast of Baja or the Sea of Cortez, Mexico (Calambokidis et al. 1990b).

 

 

 

Bottlenose dolphins (Tursiops truncates)

I was not sure how to describe this work. I am not familiar with the history so it is possible that I have misrepresented things.

In 1991 the Center for Whale Research conducted a pilot study in the Bahamas  to help document the occurrence and distribution of marine mammals in this area. This project led to the establishment of the Bahamas Marine Mammal Survey (BMMS). In the late 1980’s bottlenose dolphins had been captured from the Sea of Abaco, to establish a captive dolphin operation. Work by members of the Center for Whale Research and BMMS demonstrated that this population was small and consisted of less than 100 individuals and that live captures from this population were not sustainable (Claridge 1994). This work led to the Government of The Bahamas enforcing a total ban of live captures of bottlenose dolphins from this area.

The Center for Whale Research continued to work with BMMS until XXXX when BMMS was established as an independent research organisation. During this time we used photographic data to describe the dynamics of the bottlenose dolphin population and to identify patterns of occupancy in the coastal area off Great Abaco Island (Durban et al. 2000; Fearnbach et al. 2012a). This work provided key information on the population dynamics and habitat use of this population that has been used to inform its management and conservation. The long-term observations of this population have established that the population shows a distinct seasonal peak in calving which has evolved to avoid predation by sharks (Fearnbach et al. 2012b).

We have developed methods to study the structure of this population using molecular tools and DNA extracted from faecal samples from known individuals (Parsons et al. 2003; Parsons et al. 2006). This work demonstrated that there is a significant degree of subdivision among three study sites on the Little Bahama Bank which are separated by less than 250 km (Parsons et al. 2003). Our work estimated the amount of gene flow among these study sites and our analysis suggested that dispersal may not be strictly biased towards males (Parsons et al. 2006). We have used the same molecular tools to examine the role of kinship in structuring the population (Parsons et al. 2003) and our work has shown that males within long-term alliances are more closely related than expected by chance (Parsons et al. 2003).

 Could we maybe show some numbers here e.g. encounters per year etc.

 Not sure of the wording here. Ken can you please confirm

Calambokidis J, Cubbage JC, Steiger GH, Balcomb KC, Bloedel P (1990a) Population estimates of humpback whales in the Gulf of the Farralones, California. In: Hammond PS, Mizroch SA, Donovan GP (eds), 12 edn, Cambridge, pp 325-328

Calambokidis J, Steiger G, Straley J, Herman L, Cerchio S, Salden D, Urban R J, Jacobsen J, von Ziegesar O, Balcomb K, Gabriele C, Dahlheim M, Uchida S, Ellis G, Miyamura Y, de Guevara P PL, Yamaguchi M, Sato F, Mizroch S, Schlender L, Barlow J, Quinn Ii T (2001) Movements and Population Structure of Humpback Whales in the North Pacific. Marine Mammal Science 17:769-794

Calambokidis J, Steiger GH, Cubbage JC, Balcomb KC, Ewald C, Kruse S, Wells R, Sears R (1990b) Sightings and movements of blue whales off central California 1986-1988 from photo-identification of individuals. In: Hammond PS, Mizroch SA, Donovan GP (eds), pp 343-349

Calambokidis J, Steiger GH, Evenson JR, Flynn KR, Balcomb KC, Claridge DE, Bloedel P, Straley JM, Baker CS, von Ziegesar O, Dahlheim ME, Waite JM, Darling JD, Ellis G, Green GA (1996) Interchange and isolation of humpback whales off California and other North Pacific feeding grounds. Marine Mammal Science 12:215-226

Calambokidis J, Steigerl GH, Rasmussenl K, Urban JR, Ladron de Guevara PP, Salinas M, Jacobsen JK, Scott Baker C, Herman LM (2000) Migratory destinations of humpback whales that feed off California, Oregon and Washington. Marine Ecology Progress Series 192:295-304

Claridge DE (1994) Photo-identification study to assess the population size of Atlantic bottlenose dolphins in central Abaco. Bahamas. Bahamas Journal of Science 1:12-16

Darling JD, Calambokidis J, Balcomb KC, Bloedel P, Flynn K, Mochizuki A, Mori K, Sato F, Suganuma H, Yamaguchi M (1996) Movement of a humpback whale (Megaptera novaeangliae) from Japan to British Columbia and return. Mar Mamm Sci 12:281-287

Durban JW, Parsons KM, Claridge DE, Balcomb KC (2000) Quantifying dolphin occupancy patterns. Mar Mamm Sci 16:825-828

Fearnbach H, Durban J, Parsons K, Claridge (2012a) Photographic mark–recapture analysis of local dynamics within an open population of dolphins. Ecological Applications 22:1689-1700

Fearnbach H, Durban J, Parsons K, Claridge D (2012b) Seasonality of calving and predation risk in bottlenose dolphins on Little Bahama Bank. Marine Mammal Science 28:402-411

Ford JKB, Ellis GM, Matkin DR, Balcomb KC, Briggs D, Morton AB (2005) Killer whale attacks on minke whales: Prey capture and antipredator tactics. Marine Mammal Science 21:603-618

Parsons KM, Durban JW, Claridge DE, Balcomb KC, Noble LR, Thompson PM (2003) Kinship as a basis for alliance formation between male bottlenose dolphins, Tursiops truncatus, in the Bahamas. Animal Behavior 66:185-194

Parsons KM, Durban JW, Claridge DE, Herzing DL, Balcomb KC, Noble LR (2006) Population genetic structure of coastal bottlenose dolphins (Tursiops truncatus) in the northern Bahamas. Marine Mammal Science 22:276-298

Reilly SB, Bannister JL, Best PB, Brown M, Brownell Jr. RL, Butterworth DS, Clapham PJ, Cooke J, Donovan GP, Urbán J, Zerbini AN ( 2008) Balaenoptera musculus.  Downloaded on 15 September 2017. The IUCN Red List of Threatened Species 2008  e.T2477A9447146.

Urban J, Alvarez C, Salinas M, Jacobsen J, Balcomb KC, Jaramillo A, de Guevara PL, Aguayo A (1999) Population size of humpback whale, Megaptera novaeangliae, in waters off the Pacific coast of Mexico. Fishery Bulletin 97:1017-1024

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