Presentation on theme: "Lead Poisoning We Regulate Lead Paint, And Outlaw Leaded Fuel But, We Hunt with Lead Ammunition and Fish with Lead Sinkers and Lures."— Presentation transcript:
Lead Poisoning We Regulate Lead Paint, And Outlaw Leaded Fuel But, We Hunt with Lead Ammunition and Fish with Lead Sinkers and Lures
Lead Toxicity Known since 2 nd Century BC Damages cell membranes Disrupts enzyme production – Interfere with Vitamin D and heme production Blocks NMDA receptors which bind glutamate in neurons Effects organs – Kidneys, heart, gonads
Some Exposure in Hunters Hunters that eat more venison have more lead in blood, but very low levels typically CDC and North Dakota Dept of Health, 2008 Study of hunters
Some Steps Taken Lead shot banded from waterfowl hunting – US, 1991 – Canada, 1997 Lead in fishing lures/weights banned selectively – 13 Loon lakes in WA, May 2011 National ban on lead denied 2010 by EPA – Petition to amend Toxic Substances Control Act of 1976 by CBD, ABC, led by Michael Fry claimed 20 million birds / year killed 3,000 tons of lead on hunting grounds / year 4,000 tons in fresh water
California Condor: A Rare Species Captive breeding and release has brought the condor from 22 birds and extirpation from the wild to 300+ birds and 150+ wild birds in two decades – 4 breeding facilities – Releases southern and central California, Arizona, Baja in Mexico Condors survive in the wild only through constant and costly human assistance and intervention Figure from Wallace et al. 2007 California Condor Master Plan
Movements into high lead, north Kaibab, is expected to kill Condors
HUMANS Hunting Good, Lead Bad Conclusion: condors suffer lead poisoning from ingestion of spent ammunition sufficiently frequently to raise mortality rates well above those required for sustainability Conclusion: Hunters are the dominant predators within condors range and are important source of food for condors Recommendation: Eliminating lead threat should not be accomplished by reduction in hunting, but by replacement of lead ammunition with non-lead alternatives. Hunters should be made aware of their importance to condors Photo by Anna Fuentes (Walters et al. 2010)
Lead Is Not the Only Problem Conclusions: Successful nesting in southern California is contingent upon intensive nest monitoring because of the microtrash problem Most promising approaches to problem are cleaning up trash, returning offending adults to captivity for aversive training, promoting more natural foraging patterns – Latter may not reduce feeding of microtrash by breeders with tradition of such behavior Recommendation: Continue to clean up trash, conduct experiments with aversive training Photo courtesy of USFWS
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