Big Game Quota Setting Process
Overview for Nevada Board of Wildlife
Commissioners
The Process
Survey
and
Inventory
Population
Modeling
Develop
Arrays &
Recommend
Quotas
Harvest Data
Survey and inventory:
Species and classification
• Pronghorn – bucks, yearling bucks, does, and
fawns
• Bighorn – rams (by age class), ewes, and lambs
• Mountain Goats – adults and kids
• Elk – bulls (by point class), cows, and calves
• Mule Deer – bucks (by point class), does, and
fawns
When are surveys conducted?
Bighorn Sheep - Late Summer
Elk - Winter
Deer - Late Fall and Spring
Pronghorn – Fall to Winter
Survey and inventory:
Methods for sampling
•
•
•
•
•
Pronghorn – helicopter and ground surveys
Bighorn – helicopter
Mountain Goat – helicopter
Elk – helicopter
Mule Deer – helicopter (augmented via ground
surveys)
Population Models:
Why estimate numbers vs census?
• No survey method has perfect detection to count
all animals
• We use models based on sample of population
• Populations constantly change because of
mortality, births, etc.
• To provide a number of males and females for
determining harvestable surplus (quotas)
Population Models:
Sex ratios
Sex ratios allow for verification of population size
• Ex. Population Estimate = 1,000 animals
• Observed ratios of 30 bucks:100 does:40 fawns
– Pre-hunt population = 176 bucks 589 does 235 fawns
• 30 bucks removed by harvest:
– Should result in observed buck ratio of 25:100
• If a higher ratio is observed
– population is likely under-estimated
• If a lower ratio is observed
– population is likely over-estimated
Harvest Data
• Mandatory harvest reporting for all big game species
• Typically about 95% return rate
• # harvested animals removed from population
estimate for following year
Quota Calculation Process
Generally speaking, there are 3 steps
1) Determine projected animal harvest for each unit group
– Population estimate
– Male ratio or % of males
2) Apportion the projected animal harvest into the various weapon
classes
– Based on previous year’s demand
3) Expand the projected harvest to quotas
– Divide the projected harvest by the previous years hunter
success (3 yr average)
Demand
Measure of interest among hunter groups within a
specific unit group
Archery
Muzzleloader
Any Legal Weapon
Measure of interest based on the applicant’s
1st Choice Only
Allocation of Tag Quotas
Available Buck Harvest
Bucks allocated to Juniors
Remaining Bucks
100
- 23
77
Archery
Muzzleloader
Any Legal Weapon
5%
10%
85%
Available Bucks
4
8
65
Success Rate (%)
20%
40%
50%
Final Tag Quota
20
20
130
Demand (%)
Allocation of Tag Quotas
Desired Bull Elk Harvest
Wounding Loss
Reported Bull Harvest
100
- 15
85
Next step is to “Apportion” the Reported Harvest by Demand
Demand (%)
Available Bulls
Success Rate (%)
Final Tag Quota
Archery
Muzzleloader
Any Legal Weapon
10%
10%
80%
85 x 0.10
85 x 0.10
85 x 0.80
9
9
68
30%
48%
55%
9 / 0.30
9 / 0.48
68 / 0.55
30
19
124
Public Review and Wildlife
Commission Process
• All 17 County Wildlife Advisory Boards receive NDOW quota
recommendations end of April
• Each county holds public meeting to discuss and develop
alternative quota recommendations
• Opportunity for sportsmen and general public
• 2nd weekend in May, Board of Wildlife Commissioners hold
meeting that includes final quota determination
• County advisory boards present their alternative quotas to
Commission
• Opportunity for sportsmen and general public
• Commission makes final decision on tag quotas for all draw hunts