Lead Shot Ducks Example

[blacktailslayer]

Here is a very very simple example as why lead shot from shotguns is getting banned. There is a lot more information that goes into these models, but it can get very complicated. These are numbers that we used in a wildlife dynamics/statistics class at Oregon State University. This is just an example and does not represent any area.

Maximum adult ducks supported by reserve (food limitation): 40,000

Maximum territories (nest sites on reserve): 1,000

Maximum ducklings produced per pair with territory: 16

(These are just the maximums and does not mean the numbers will be reached)

Density dependent relationship- duckling production(Ricker scramble)

Male Annual Survival Rate

Duckling: 25%

1 Year-old: 60%

2 Year-old: 60%

3 Year-old: 70%

Adult: 80%

Female Annual Survival Rate

Duckling: 25%

1 Year-old: 60%

2 Year-old: 60%

3 Year-old: 70%

Adult: 85%

Suppose the maximum number of ducks allowed to be shot without over-harvesting would be 550 male 1 year-olds and 650 female 1 year-old ducks. That would be a total harvest of 1,200 ducks with a biomass of 900kg. If lead shot from shotgun shells has reduced the fertility of your ducks, cutting their annual duckling production in half. With cutting the annual duckling production in half from 25% to 13%; our harvest goes down. The maximum harvest goes down to 110 male 1year-olds and 210 female 1 year-olds. The total harvest is now only 320 ducks with a biomass of 240kg. I choose both male and female 1 year-olds to gain the maximum harvest and maximum biomass without making the population go extinct. I know that it would be impossible to only take 1 year-olds, but this is only an example. This would only happen if lead shot was bad enough to decrease duckling production 50% in this bird reserve that allowed duck hunting. Hunting that want to hunt for years to come and let generations after them enjoy the same benefits would understand why some places are banning lead shot. Remember this is only an example that does not say every place lead shot is used is going to decrease duckling production down 50%

This is just a very simple example for the hunters that don’t understand how much lead shot in the environment can really affect wildlife. We all know that it is bad, but this may show you how bad it really can be.

[blacktailslayer]

Lead Shot Ducks Example

Sorry my copy and paste did not work. Here is a link to where I posted the example.

http://www.ifish.net/board/showthread.php?t=239927