Chris Johnston , B.Sc.

Chris Johnston , B.Sc.

Age Lab Technician
Biological & Ecosystem Sciences Branch


Current IPHC Responsibilities:

  • Production age reading of Pacific halibut is my primary duty.
  • Assist with otolith processing as necessary
  • Prepare otoliths for offsite storage.
  • Preparation and reading of otoliths for research.
  • Assist with Seacat profiler data organization and editing and other Seacat related duties.
  • Answering IPHC incoming phone calls and transferring calls to appropriate individuals.


  • University of Western Washington 1985-1988 (Biology)
  • University of Montana 1983-1984
  • Cornish Institute 1980-1982

Previous Work Experience:

Age Reader—Age Determination Unit, Alaska Fisheries Science Center (AFSC), National Marine Fisheries Service (NMFS). Seattle WA (1990-2013). Primary duties of this position included:

  • Preparation and ageing otoliths from north Pacific groundfish species on a production basis (9,000 thousand structures per year).
  • Production ageing expertise in Pacific cod, pollock, arrowtooth flounder, flathead sole, rex sole and Dover sole.
  • Preparation techniques routinely used included break and burn, break and bake, and thin sectioning, sanding and polishing.
  • Photographing and measuring otoliths using ImagePro software.
  • In addition, I have aged Pacific cod from archeological middens on Kodiak Island.
  • At-sea sampling on NMFS trawl and pot surveys (identifying fish and invertebrates to species, recording specimen data and collecting biological samples such as otoliths and stomachs.
  • Instruct groups of middle school students on fish ageing technique and importance of age data during NOAA Science Camp program and school tours.
  • Keyworker for Combined Federal Campaign (CFC), a program where employees contribute to charitable organizations through payroll deduction. Keyworker duties include describing the programs and eligible charities to AFSC employees and facilitating enlistment into CFC payroll deduction plan.
  • Featured in NOAA Microworlds video segment “How Old is a Fish?” in 2011.  This video is used in Washington state middle schools to provide real world examples of how microscope techniques learned in the classroom are used by scientists at NOAA.

Seasonal port sampler and age room assistant—International Pacific Halibut Commission (1988-1990):

  • Collected logs and otoliths from commercial Pacific halibut deliveries; transferred otoliths as they came in from the field; measured otolith length and weight; stored otoliths in vials.


  • Kastelle, C. R., Helser, T. E., McKay, J. L., Johnston, C. G., Anderl, D. M., Matta, M. E., and Nichol, D. G. 2017. Age validation of Pacific cod (Gadus macrocephalus) using high-resolution stable oxygen isotope (δ 18O) chronologies in otoliths. Fish. Res. 185:43-53.
  • West, C. F., Wischniowski, S., and Johnston, C. 2012. Pacific Cod (Gadus macrocephalus) otoliths as a paleothermometer: otolith oxygen isotope reconstruction in the Gulf of Alaska. Journal of Archaeological Science. 39(10)3277-3283.
  • Johnston, C. G. and Anderl, D. M. 2012. Pacific cod (Gadus macrocephalus) in Age determination manual of the Alaska Fisheries Science Center Age and Growth Program. NOAA Professional Paper NMFS 13. Mary Elizabeth Matta and Daniel K. Kimura (editors)
  • West, C.F., Wischniowski, S., and Johnston, C. 2011. Little Ice Age Climate: Gadus macrocephalus otoliths as a measure of local variability. In The Archaeology of North Pacific Fisheries, edited by Madonna Moss and Aubrey Cannon, pp 31-44. University of Alaska Press, Fairbanks.
  • Kastelle, C.R., Anderl, D.M., Kimura, D.K., and Johnston, C.G. 2008. Age validation of Dover sole (Microstomus pacificus) by means of bomb radiocarbon. Fishery Bulletin 106(4):375-385.

Awards and Achievements:

  • 2011 Telly Award for NOAA Microworlds video—a film for use in Washington state middle schools which provides real-world examples of how microscope techniques learned in the classroom are used by scientists at NOAA