Current State of Our Orcas

Highline Community College

Killer Whales- Orcas

• Orcinus orca

• Largest member of the dolphin family, Delphinidae

• Identifying traits– Tall dorsal fin– Saddle patch behind dorsal fin– White patches on sides, belly and behind eyes

Orca Biology

• Average Birth Weight: 395 lbs

• Average Adult Weight: 2.6 – 9 tons– Males are larger than females

• Lifespan:– Males ~40 years– Females >60 years

• Sexually mature ~13 years

Orca Natural History

• Found in all the world’s oceans

• Travel in pods from 3 to >150 members

• Feed on fish, squid and marine mammals

Transient vs. Resident Orcas

Transients Residents

Habitat Offshore Nearshore

Food Marine Mammals

Fish

Pod Size 3-5 >20

Vocalization Quiet Very Vocal

Resident Orcas

• Resident orcas live in coastal areas feeding mostly on fish

• Live in extended familial units called pods– Pods are matriarchal

• Northeast Pacific resident orcas are found from Puget Sound to Alaska– Puget Sound orcas are Southern Resident Orcas

Southern Resident Orcas

• Consists of three pods: J, K and L

• Summer in the area around the San Juan Islands feeding on salmon runs

• Winter on outer coast, but do not know where

Dead Orcas

                                    

    

State of Southern Resident Orcas

• Almost 20% orcas died between 1995 and 2000.

• Reproductive females have not produced young in ten years.

• Only four adult males in the entire community of 80 whales.

Puget Sound Orcas and PCBs

• Highest levels of PCBs in blubber of any marine mammal in the world– Average almost 150 ppm

– <10 ppm PCB is known to cause immune problems in seals

• Dead female transient orca on Dungeness Spit in May 2002 – 1000 ppm PCB

– 12ppm- EPA’s standard for marine sediments

Polychlorinated Biphenyls(PCBs)

Cl

Cl

Cl

Cl

PCBs• Highly stable oily fluids and solids

– Transformers, pesticides, etc

• Fat soluble – Reside in fatty tissue

• Block hormone activity– Destroy normal immune function– Cause liver cancer, pituitary tumors, leukemia, and lymphoma

• Banned in U.S. since 1977

Ecosystem Review

• Ecosystem– Organisms interacting with environment and

each other through a food chain

• Food Chain – Biomass moves from one organism to

another as each eats a lower member and, in turn, is eaten by a higher member

Generalized Ecological Pyramid

2° Consumers3° Cons.

1000 g Biomass

100 g

10 g

1 g

Primary ProducersPrimary Consumers

Idealized Puget Sound Ecological Pyramid

1000 g

100 g

10 g

1 g

PhytoplanktonZooplanktonSalmon

Orcas

Pollutants

• Pollutant– Adversely affects the health, survival,

or activities of living organisms

– Persistent Organic Pollutant• POP• Stable, Long Lasting• Includes DDT and PCBs

Factors Influencing Impact of Pollutants

• Solubility– Water soluble pollutants

• Move easily through environment

– Fat soluble pollutants• Need a carrier • Long-lasting in body’s fatty tissue

• Persistence– More stable– Longer to break down– More harm it can do

Pollutants in the Food Chain

• Bioaccumulation– Cells increase the concentrations of molecules

relative to the environment

• Biomagnification– Concentration of pollutants increases as they

move up the ecological pyramid– Only 10% of biomass, but most of the pollutant

is transferred

DDT in a Long Island Estuary(from Woodwell, Wurster and

Isaccson, 1967)

Trophic level Organism DDT in wet weight of whole organism

Primary Producer

Green Alga 0.08 ppm

Primary Consumer

Mud Snail 0.26 ppm

Secondary Consumer

Summer Flounder

1.28 ppm

Tertiary Consumer

Ring-billed Gull

75.5 ppm (1000x initial concentration)

Idealized Puget Sound PyramidWith PCBs

1000 g

100 g

10 g

1g

PhytoplanktonZooplanktonSalmon

Orcas

1 g

Trophic Level %PCBPhytoplankton 0.1%Zooplankton 1%Salmon 10%Orcas 100%

The ‘Double Whammy’

• In blubber, PCBs are not very harmful.

• Low salmon runs force orcas to metabolize more blubber to survive.

• The blubber releases PCBs into the blood, destroying the immune system.

• Therefore, starvation increases the lethality of the pollutant.

Sources of Pollutants in the Environment

• Point Source– Specific location of concentrated

pollutants• Factory waste• Sewage

• Nonpoint Source– Scattered or diffuse sources of pollutants

• Golf courses• Agriculture