Climate data collected during sonar estimation of summer chum and pink salmon in the Anvik River, Alaska, 2023

Dual-frequency identification sonar (DIDSON) was used to estimate adult summer chum salmon Oncorhynchus keta and pink salmon O. gorbuscha passage in the Anvik River from June 15 to July 26, 2023. Apportionment to species was determined using data collected from tower counts. A total of 60,665 (SE 778) summer chum were observed to have passed the sonar site, but no pink salmon were observed in 2023.A beach seine sample fishery was conducted to collect age, sex, and length information. A high-water event necessitated removing the sonars from the water from July 10 until July 24 and the sample fishery was discontinued after July 7. Due to the timing and extended duration, it was not possible to estimate the missing portion of the run. The range of ensonification was considered adequate for most fish that migrated upstream. Climate data was collected every day at 1800 and water temperature data was collected hourly.

Methods
Climatic and hydrologic data were collected at approximately 1800 each day at the sonar site. River depth was monitored using a staff gauge marked in 1 cm increments. Change in water depth was presented as negative or positive increments from the initial reading of 0 cm. Air temperature and subjective notes about wind speed and direction, cloud cover, and precipitation were also recorded. Water temperature was measured using a HOBO data logger, which electronically recorded the temperature every hour, on the hour, for the duration of the project.