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Recovery Strategy for the Transient Killer Whale [Proposed]

Appendix C: Anthropogenic Threat Classification Table Definitions

Note that these are taken from the Draft Species at Risk Act Implementation Guidance,   Guidelines on Identifying and Mitigating Threats to Species at Risk, September 27, 2006 produced by Environment Canada.

Stressor Categories

Broad definition indicating the type of threat.

Habitat Loss or Degradation, Exotic or Invasive Species, Changes in Ecological Dynamics or Natural Processes, Pollution, Accidental Mortality, Consumptive Use, Disturbance or Persecution, Climate and Natural Disasters, Natural Processes or Activities

Threat Definitions

General Stressor
Typically the general activity causing the specific threat.  To be determined by status report author or recovery team/planner.
Specific Stress
The specific factor or stimulus causing stress to the population.
Indicated by an impairment of a demographic, physiological or behavioural attribute of a population in response to an identified or unidentified threat that results in a reduction of its viability.
Indicate whether the threat is widespread, localized or unknown across the species range.
Indicate whether the threat is historic, current, imminent, anticipated or unknown.
Indicate whether the threat is a one-time occurrence, seasonal, continuous, recurrent, or unknown.
Causal Certainty
Indicate whether the best level of evidence suggests demonstrated, expected, plausible, or unknown linkage between stressor and effect on population viability.
Indicate whether the severity of the threat to the population is high, moderate, low or unknown.
Pollutants That May Pose a Risk to Transient Killer Whales
Pollutant Use/Source Persistent Bio-accumulate Risk



pesticide used in some countries, banned in North America, persists in terrestrial runoff 30 years post ban, enters atmosphere from areas where still in useyesyesreproductive impairment, immunosuppression, adrenal and thyroid effects


Polychlorinated Biphenyl s

electrical transformer and capacitor fluid, limited use in North America but enters environment from runoff, spills and incinerationyesyesreproductive impairment, skeletal abnormalities, immunotoxicity and endocrine disruption
Dioxins and Furansby-product of chlorine bleaching, wood product processing and incomplete combustion. Mills less of a source now. Current sources include burning of salt-laden wood, municipal incinerators, and residential wood and wood waste combustion, in runoff from sewage sludge, wood treatmentyesyesthymus and liver damage, birth defects, reproductive impairment, endocrine disruption, immunotoxicity and cancer


Persistent Polycyclic aromatic hydrocarbons

by-product of fuel combustion, aluminium smelting, wood treatment, oil spills, metallurgical and coking plants, pulp and paper millsyesnocarcinogenic

Flame retardants, esp. PBBs and PBDEs

Polybrominated diphenyl ethers

flame retardants; in electrical components and backings of televisions and computers, in textiles and vehicle seats, ubiquitous in environment.  2/3 product PBDEs banned in Europe. Same two products withdrawn from North American marketplace in 2005, but one (deca) product still used globally.yesyesendocrine disruption, impairs liver and thyroid


Perfluro-octane sulfonates

stain, water and oil repellent (included in Scotchgard until recently), fire fighting foam, fire retardants, insecticides and refrigerants, ubiquitous in environmentyesyes but in blood, liver, kidney and musclepromotes tumour growth




antifoulant pesticide used on vesselsyesYesunknown but recently associated with hearing loss


Polychlorinated paraffins

flame retardants, plasticizers, paints, sealants and additives in lubricating oilsyesyes endocrine disruption


Polychlorinated napthalenes

ship insulation, electrical wires and capacitors, engine oil additive, municipal waste incineration and chlor-alkali plants, contaminant in PCBs yesYes endocrine disruption


Alkyl-phenol ethoxylates

detergents, shampoos, paints, pesticides, plastics, pulp and paper mills, textile industry found in sewage effluent and sedimentsmoderatemoderateendocrine disruption


Polychlorinated terphenyls

fire retardants, plasticizers, lubricants, inks and sealants, enters environment in runoffyesyesendocrine disruption and reproductive impairment
References: Primarily Grant and Ross 2002, but also Lindstrom et al. 1999, Hooper and MacDonald 2000, Kannan et al. 2001, Hall et al. 2003; Van deVijver et al. 2003, Rayne et al. 2004, Song et al. 2005