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Bioaccumulation: A Case Study of British Columbia’s Killer Whales Lesson 1. Killer Whales of British Columbia. There are 3 different types of killer whales They have different diets , ranges, languages, behaviour & social organization (Bigg, Ellis, Ford)
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Bioaccumulation: A Case Study of British Columbia’s Killer WhalesLesson 1
Killer Whales of British Columbia • There are 3 different types of killer whales • They have different diets, ranges, languages, behaviour & social organization (Bigg, Ellis, Ford) • The three types are Residents, Transients & Offshore killer whales • The different kinds do not mate with one another! • (Barrett-Lennard)
So much is known because killer whales can be told apart as individuals thanks to the work of Dr. Michael Bigg Dorsal Fin – shape, nicks & scratches Saddle Patch A12, Scimitar, 1941 A33, Nimpkish, 1971 Photos: Jackie Hildering
Resident Killer Whales • Eat fish – Mainly salmon • The fish can not hear in the range of the calls and salmon has very predictable spawning behaviour • This means that residents can afford to be: • Very social – they don’t leave their mothers, travelling in matrilines • Very vocal – each matriline sounds a little different • Because each matriline sounds different, they know exactly who is family and who is not. This if very important for mating! It allows them to avoid inbreeding.
Matriline exampleResident killer whales – A30s A30 female 1947 “Tsitika” A6 Male 1964-2000 “Strider” A38 Male 1970 “Blackney” A39 Male 1975 “Pointer” A50 Female1984 “Clio” A54 Female 1989 “Blinkhorn” A75 2001 “Cedar” A84 2005 No name A72 Female1999 “Bend” Know female by DNA
Transient Killer Whales • Eat marine mammals • The marine mammals can hear them! • This means that transients: • Must be very quiet until they are sure they are going to get their prey • Family structure less stable
Resident killer whale Salmon Herring Zooplankton Phytoplankton
Transient killer whale Seals Salmon Herring Zooplankton Phytoplankton
Food Web Transient killer whale Resident killer whale Seal Humans Salmon Herring Zooplankton Phytoplankton
Transient killer whales Persistent Toxins Higher = more Seal Resident killer whales Salmon Salmon Herring Herring Plankton Plankton
Killer whale calf Resident killer whale Salmon Herring Zooplankton Phytoplankton