(29C) Population Size

09222019, 11:46 AM
(This post was last modified: 09222019 03:28 PM by SlideRule.)
Post: #1




(29C) Population Size
An extract from Willow Creek Drainage Fishery Inventory, Regional Fishery Management Investigaions, Project No. F71R8
"Tributary Evaluation Population Assessments … Estimates from the maximum likelihood method were calculated with the aid of computer program modified from Platts, et al. (1983) for the double density version Osborne 1 computer. The program provides point estimate, 95% confidence limits, and test for constant catchability using chisquare goodness of fit. Calculations for the two pass and mark recapture estimators were made using programs written for the HewlettPackard (HP) Model 29C calculator (Appendices 1 and 2). These programs remove bias and calculate point estimate and 95% confidence limits. All confidence limits expressed in this report are at the 95% level. … Mainstem Evaluation Population Assessments … We estimated population densities on one section of lower Willow Creek, one headwater section of Willow Creek, and one headwater section of Grays Lake Outlet. A generatorpowered Coffelt shocking unit mounted in a drift boat was utilized to collect fish in lower Willow Creek. In order to estimate the population of game fish, successive trips were made through a 4.8km section located between Kepps Crossing and Clowards Crossing, marking or tagging fish on the initial run and making recaptures the following day. Nongame fish were numerous but no attempt was made to capture them due to time constraints. We used the Peterson mark recapture estimator (Everhart et al 1976) programmed into a HewlettPackard Model 29C calculator to obtain point estimates and 95% confidence limits of the population size. Total length of all gamefish captured was measured to the nearest millimeter and we took weights from a representative sample of the fish in order to calculate a condition factor. To estimate population size in the headwater section of Willow Creek we used the generatorpowered backpack shocker to collect fish on two successive passes and then calculated the estimated population size using the HP 29C calculator program described earlier. All trout captured were measured, tagged and released. Nongame fish were captured on the first pass to obtain length frequency information and to obtain a rough estimate of species composition. A Peterson single mark recapture estimate was made on a 550m segment of Grays Lake Outlet above the barrier falls. We capturedfish with the backpack shocker, measured length and weight, jaw tagged them and released them. Fry and nongame species were counted and measured but no attempt was made to estimate the numbers present. The estimated number of age 1+ and older fish were calculated on the HP 29C calculator program. … APPENDIX Appendix 1. Calculator program for HewlettPackard model 29C used in estimating population size from two successive passes pg. 86 Appendix 2. Calculator program for HewlettPackard model 29C used to estimate population size for the markrecapture method pg. 89 BEST! SlideRule url updated: copy & paste Project v17c Region 6 Willow Creek Drainage Fishery Inventory in search this site for working url link. 

09222019, 02:27 PM
Post: #2




RE: (29C) Population Size
Sorry SlideRule, the link does not work. The message is: Bad Request  Invalid URL
Pedro 

09222019, 07:04 PM
Post: #3




RE: (29C) Population Size
(09222019 02:27 PM)PedroLeiva Wrote: Sorry SlideRule, the link does not work. The message is: Bad Request  Invalid URLYes, this is the corresponding link for downloading the corresponding PDF of about 99 pages Pedro https://collaboration.idfg.idaho.gov/Fis...Region.pdf 

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