11-10-2010, 07:24 PM
So I got an answer from Damon today on my question on the 90% of the fish die of old age theory- here is his response:
We collect trend data of our fish populations through an intensive gillnetting survey, conducted in the spring every year. From this data, we derive yearly mortality, year class strength, fish abundance, species composition, and growth rates.
Our creel surveys that we conduct regularly allow us to estimate angler effort, catch rates and harvest rates amongst other valuable data sets.
It's important to note that only 10,000-20,000 fish are harvested on Henrys every year. 4 out of 5 fish caught are released. Ice angling harvest and release rates are similar to open water angling. Our exploitation rate (percentage of the fish population that die due to angling) is less than 5% annually.
Natural mortality would encompass all other types of mortality not related to angling. Without question, most fish at Henrys succumb to factors not related to angling.
Fewer than 1,400 fish are normally harvested during November. We have determined that an additional month of angling on Henrys will not jeopardize the fish population at Henrys, either in size or numbers.
We normally don't get involved in blogs and forums, but you are welcome to use the numbers I've given you.
Damon Keen
Regional Fishery Biologist
Henrys Lake
Idaho Fish and Game
[signature]
We collect trend data of our fish populations through an intensive gillnetting survey, conducted in the spring every year. From this data, we derive yearly mortality, year class strength, fish abundance, species composition, and growth rates.
Our creel surveys that we conduct regularly allow us to estimate angler effort, catch rates and harvest rates amongst other valuable data sets.
It's important to note that only 10,000-20,000 fish are harvested on Henrys every year. 4 out of 5 fish caught are released. Ice angling harvest and release rates are similar to open water angling. Our exploitation rate (percentage of the fish population that die due to angling) is less than 5% annually.
Natural mortality would encompass all other types of mortality not related to angling. Without question, most fish at Henrys succumb to factors not related to angling.
Fewer than 1,400 fish are normally harvested during November. We have determined that an additional month of angling on Henrys will not jeopardize the fish population at Henrys, either in size or numbers.
We normally don't get involved in blogs and forums, but you are welcome to use the numbers I've given you.
Damon Keen
Regional Fishery Biologist
Henrys Lake
Idaho Fish and Game
[signature]