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Cetaceans(order Cetacea)

Whales, Dolphins and PorpoisesTwo kinds of whales and dolphins

Mysticetes= Baleen whalesOdontocetes= Toothed whales, porpoises and

dolphins

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Distribution of Killer Whales in N PacificKrahn, M.M., et al.2002. Status reviewof SouthernResident killer whales (Orcinusorca) under theEndangeredSpecies Act. U.S.Dept. Commer.,NOAA Tech. Memo.NMFS-NWFSC-54,133 p.

(available off theclass web)

Offshores & Transients

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N. Pacific OrcaDynamics

Communities, superpods, pods,subpods found all along coastfrom PS to Arctic

Average size is ~150 individuals for acommunityBest guess of 1000-1250 Killer whales in Eastern N Pacific

Communities in Price William Sound andour Southern Residents well studiedNorthern residents less well studiedEcholocation clicks are repeated(pulsed) sounds in the 1 to 10 Khz range

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Salish Sea Orca History

No wide-spread hunting bynative AmericansTribal stories for orca creationpropose them to be human (inmany instances)hunted by military along withseals and sea lions in PS,1945-1967

Aquarium trade capture1965-1972

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4 Sympatric Communities

OffshoresTransients

Northern ResidentsSouthern Residents

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Differences in dorsal fins

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Killer Whale Discrete Calls

Discrete dialects (acoustic clans) that are semi-stable through time

SR s have 1 clan, NR 3 and SAR 2

Time

F r e q u e n c y

( H z

)

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Ecolocate, sing & whistle

echolocation

singing

whistle

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Lets look at each group

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Transients

Communities Found all along Americas, Arctic to AntarcticMore abundant in colder water

Feed on other marine mammalsPod structure is small and inclusive of members of either sexlone bulls live outside of pod structure Morphological differences

Fin shape, animal size Acoustic differences Actively avoid the fish-eatersUnpublished genetic data suggestsdivergence >10,000ybp, unique species In PS, @25 individuals in

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Recent Transient Hunting

A pod of transients were in Hood Canalfor 2 mo last winter (Jan-Feb 2003)Take of ~600 seals, roughly half the populationT14, one of the whales in the transient pod,was captured in Hood Canal in the early 1970 sfor the aquarium trade, then subsequently

released after a public outburst against thecaptures. If retained, he would have been theonly transient ever studied in an enclosedaquarium

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Hunting video

This videotaken off the

Ca coast in1998, similar feedingstrategy used

by transientswhen theywere in PS

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Offshore Community

Only discovered in early 1980 s Least information for these individualssince they rarely come in shore

Appear to live further offshore than thecontinental shelf (>70km)200+ individualsObserved as far south as S. California

Genetically similar to southern residentsin their maternal lineage (mtDNA), andfin structure is similar too, but these twogroups have never been observedtogether Thought to be fish-eaters

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Offshore encounter

A group of offshores was observed onMay 1st, 2003 in Haro Strait

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The SouthernResidents

3 (4) pods in the communityJ,K and L Pods (L-10 subpod)Salmon (90%) of diet

Known to take mammals and other fish on occasionJ-pod year-round in Salish Sea

Usually winter in PS, rarely observed outside of Salish SeaK and L pods go offshore Dec-May

Observed both N and SReturn within a week of each other usuallyReunion of three pods includes singing and rubbing Return precedes local salmon runs by 1-2 weeks

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Southern Residents

Use top and bottom of water columnDives are deep and directCalving interval ~5yrs (0-12)1950 s population ~125individuals

despite random targetpractice & bad reputationaquarium trade took ~45individuals from the populationbetween 1964-1972

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Pod Structureof residents and off-shores

Matrilinesbrothers and

sisters swim together Breeding occurs cross-matrilines

If one pod is male-poor, the other pods couldpotentially suffer If one pod loses its females, that pod will go extinct

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Washington

V a n c o u v e r I s l a n d

British Columbia

Summer distribution of southern residents

Genetic studies:

Hoelzel et al. 1991, 1998,Barrett-Lennard 2000

Discrete populationthat is genetically distinctfrom the northern residentpopulation in B.C.

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J Pod Movement Sequences(Summer 2001)

CommittedTurn around

Back/Forth50/50

Data analysis by Erin Heydenreich, data fromthe international sighting network

Clockwise movementcommon

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Molecular studies

MitochondrialDNA analyses(not shown) link

maternal lineageof offshores tothe residentsMicrosatellitedata (shown atright) separatesresidents fromother KWs

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More N&SR s Most well known whales in the worldSRs did not adoptSpringer in 2002Luna still in Nootka Sound Fearing that a lonely killer whale could injure or killsomeone, a team of Canadian authorities andscientists is debating the whale's fate, while policeare cracking down on people who pet the creature.The three-and-a-half year-old orca, nick-namedLuna, is "pathologically social," says marine biologistLance Barrett-Lennard of the Vancouver Aquariumin this west coast Canadian city.

NR s creating new pods, SR s might be One expatriate, Lolita, still alive andliving in Florida

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Lolita

Last living capturefrom the Southern

ResidentsCurrently at SeaWorld, Florida

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Current SRpopulation tally

Is thepopulationreboundingfrom its most

recentdecline?020

40

60

80

100

120

1970 1975 1980 1985 1990 1995 2000 2005

Year

#

i n S R P o p u

l a t i o n

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Excerpted and updated from:

Dynamics of small populations

A presentation provided by:

Paul R . Wad e

National Marine Mammal Laboratory Alaska Fisheries Science Center NOAA FisheriesSeattle, WA

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The dynamics of small populationsbecome different from large populations

Small populations are at risk of extinction

Naturally rare populations exist that appear stable (e.g., vaquita, Carrribean monk seal)Populations driven to low numbers by human-caused factors

harvestbycatchhabitat degradation

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Small Populations are the focus of ecological study because of conservationand endangered species issues

Stochastic demographic and geneticfactors determine the minimum sizeof a viable population

3 demographic factorsdemographic stochasticityenvironmental stochasticitycatastrophes

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Populations driven to low numbers face a riskof extinction just from being a small population

Depensation/Allee effects

critical density below which the population islikely to go extinct (in a probabilistic sense)

Stochastic population dynamics

Demographic and environmental variance cancause a small population to go extinct justfrom chance alone

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Causes of Allee effects

Genetic inbreeding and loss of heterozygosityinbreeding depression -- expression of deleteriousrecessive alleles

loss of diversity through drift -- drift occurs much morerapidly in small populationsBehavioral/demographic causes such as a reduction incooperative interactions

Shortage of fertilization or mating opportunitiesanti-predator strategies become inefficient in smallgroups of prey

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0.000

0.010

0.020

0.030

0.040

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Population level (as fraction of K)

P o p u

l a t i o n g r o w

t h p e r c a p

i t a

( n u m

b e

r s o

f a n

i m a

l s / p o p u

l a t i o n s

i z e

)

Allee effect

No Allee effect

Allee effect

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Allee effects

Difficult to studysmall sample sizes

need population growth at different populationlevels to detect (contrast) historical/retrospective analysis important butdifficult to interpret

Meta-analysis found evidence of Depensation in some fish stocks

f h f

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PVA estimates for the extinction of SR

Full record, no catastrophes Full record, 2% catastrophe1992-2000 record, no catastrophes 1992-2000 record, 2% catastrophe

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PVA estimates for the extinction of SR

NOAA NMMLPVA runssuggest that asingle tragedyof major proportions(Exxon Valdez)

could wipe outthe SRpopulation

Wh b i bili

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What about variabilityin survival or birthrates?

Both survival(shown at right

for old males)and fecundity(bottom right)show periodicityover the last30 years

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0.900.91

0.920.930.940.950.96

0.970.980.991.00

1973 1977 1981 1985 1989 1993 1997 2001

Year

S u r v

i v a l

6 year model Annual

Environmental variance in survival

Hard to predict fate of a particular population

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Hard to predict fate of a particular population2 populations of pinnipeds harvested to verylow levels

Northern elephant sealsreturned from ~100 to more than 80,000

Japanese sea lion (sub-species)went extinct

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Demographic stochasticity (N=78)

0

50

100

150

200

250

2000 2020 2040 2060 2080 2100

Year

P o p u

l a t i o n s i z e

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0

500

1000

1500

2000

2500

2000 2020 2040 2060 2080 2100

Year

P o p u

l a t i o n s i z e

Demographic stochasticity (N=800)

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Some rules of thumb

~50 individuals allows a population to escape from risk of extinction from demographic variance (in the absence of

Allee effects)

~500 effective population size allows a population toescape genetic inbreeding problemsIn populations of modest size, environmental varianceperhaps much more important than demographic

Recent recognition that catastrophic events or longer term regime shifts may be more important than inter-annual variation

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