Ich Sampling to inform need for Fall Flows Hoopa Valley Reservation

The Hoopa Valley Tribal Fisheries Department installed a temporary adult salmonid weir during the last week of August in the lower Trinity River on the Hoopa Valley Reservation. Its purpose was to gather data on age composition, spawning escapement, tribal subsistence harvest, and for the collection of gill arch samples on Chinook salmon to quantify Ich trophonts. Beginning on September 11, Chinook salmon were selected for tribal harvest based on their physical condition (chrome, bright, dark), with mostly bright fish being harvested. Immediately after being dispatched, one left and right gill arch closest to the mouth was extracted with scissors, placed in a Ziploc bag and put on ice. Up to five fish were sampled daily for a total of ten gill arches. Once collected, the samples were taken onshore to be further examined. Pathological evaluation of the freshly sampled gill arches was conducted with a stereoscope using 10x magnification. Both sides of the left and right gill were examined for Ich trophonts, which were then enumerated and recorded in separate columns in an Excel spreadsheet. The maximum number of trophonts observed between both gills was also recorded in its own column.



The recorded data was provided to KFHAT and FARs groups during weekly calls.

Project Benefits: Accurate information through the management window will ensure informed flow decisions are being made. This flow action has been instrumental in preventing a repeat of the fish kill of 2002. Given the dry hydrologic conditions of this water year having good real time information will be critical.