1 / 11

Methods for analysis of Chinook scales coastal and interior Oregon

Methods for analysis of Chinook scales coastal and interior Oregon. The Fish Life History Analysis Project Ben Clemens Lisa Borgerson Kanani Bowden Stephanie Gunckel. Fish Life History Analysis Project. Project history Project transitions Bottom-line: Chinook (and other spp.) monitoring

bono
Télécharger la présentation

Methods for analysis of Chinook scales coastal and interior Oregon

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Methods for analysis of Chinook scalescoastal and interior Oregon The Fish Life History Analysis Project Ben Clemens Lisa Borgerson Kanani Bowden Stephanie Gunckel

  2. Fish Life History Analysis Project • Project history • Project transitions • Bottom-line: Chinook (and other spp.) monitoring • “Small, developing project with a big (and growing) plate”

  3. Scale Preparation • Most scales mounted on gummed cards • Plastic impressions made with a heat press • Scales of juveniles mounted on glass slides • Viewed with microfiche projector • Digital image system (Image Pro Plus, FlashPoint frame grabber, Leitz microsope, Cohu B&W camera)

  4. Fish Age • Age salmon by the number of winters • Fall/winter spawning salmon: Add “1” for the first winter

  5. Accuracy and Precision Accuracy • Test readers with known age scales--tagged fish (CWT, PIT) • Multiple readers (catch recording errors, lapses in judgment) Precision • Multiple readers-agree on interpretation diffs • Train by reading scales read by prev. readers • Test on a standard set of scales

  6. Validation • Known age tagged fish • Natural marks • Pedigree study • Mark and recapture • Marks on structure, chemical or temperature induced • Beamish, R.J. and G.A. McFarlane. 1983.. Trans. Am. Fish. Soc. • Campana, S.E. 2001. J. Fish Biol.

  7. Challenges • Sample sizes • Scale quality • Resorption/regeneration • Unclipped hatchery fish • Within-basin life history diversity • Ocean entrance: check vs. annuli • “Reservoir” life histories • South-migrating stocks: less distinct annuli • Lack of “known” age/disposition samples: Validation

  8. Challenges • “Small, developing project with a big (& growing) plate” • Ability to adapt (learn, grow, train new staff): challenging, given workload.

More Related