DOI: 10.5061/dryad.0k6djh9z4
title: Chum salmon escapement on Bonanza River in Norton Sound, Alaska

description: Bonanza River flows 40 rkm south from the Kigluaik Mountains and drains
 into Safety Sound approximately 39 km northeast of Nome, Alaska. Chum,
 pink, and coho salmon are the predominant species that return to the
 Bonanza River. A fixed-picket weir was installed  approximately
 11 rkm above the Bonanza Bridge on the Nome-Council Highway (GPS
 coordinates 64°32.964ʹN, 164°35.812ʹW). The Bonanza River weir
 enumerated chum salmon for three seasons from 2018 to 2020. Chum salmon
 escapements were 7,903 in 2018; 8,824 in 2019; and 2,471 in 2020. In 2018
 and 2019, high water delayed installation of the weir and therefore the
 beginning of the run may have been missed. Additionally, in 2019 high
 water forced weir operations to stop before the proposed end date, so it
 is likely the end of the chum salmon run was missed. In 2020, the weir
 went in according to schedule and counted the beginning of the run, but
 personnel issues, exacerbated by COVID-19 protocols, resulted in early
 termination of the project, and likely caused missed counting at the end
 of the run. High water that hindered counting on Bonanza River in 2018 and
 2019 also hindered counting operations on other Subdistrict 1 rivers, and
 as a result aspects of Objectives 1 and 2 could not be completed for all
 project years. Age, sex, and length data were collected from chum salmon
 passing through the weir in all three years. Minimum sample size
 requirements to evaluate Objective 3 were met in 2018 and 2020, but not in
 2019. In 2018, chum salmon were predominantly 4 years old and in 2020 chum
 salmon were predominantly 5 years old. This project indicated that using
 existing methods, such as weirs and aerial surveys, to estimate Bonanza
 River’s contribution to chum salmon abundance in Subdistrict 1 provide a
 reasonable approximation of chum salmon escapement in the absence of an
 enumeration project on Bonanza River.
description: Escapement data were
 collected by identifying salmon by species and counting them through a
 fixed picket weir on Bonanza River, Norton Sound, AK. Counts were
 conducted several times a day when the weir was ‘open’ to allow for fish
 passage. Escapement data is comprised of daily counts for each salmon
 species enumerated through the weir and summaries of cumulative count and
 cumulative proportion of run.  Environmental data include water
 temperature and relative water height.  Water temperature was recorded
 using a handheld thermometer submerged in the river twice daily: once in
 the morning (8:00 am) and once in the evening (8:00 pm). Water temperature
 was also collected every 6 hours using a HOBO logger (Onset Computer
 Corporation) and data were downloaded at the end of the season.  Relative
 water height was recorded using a stream gauge (in decimal feet) at the
 same time water temperature was taken.  At the end of the season water
 height in decimal feet was converted to centimeters for reporting. 
 Relative water height was used to assess river height through a season and
 should not be compared between years because the water gauge was not
 located in the exact same spot each year.  Age, sex, and length (ASL) data
 were collected predominately from chum salmon and other salmon species
 when time allowed.  Sex of the salmon was determined using external
 characteristics such as kype development and presence of an ovipositor. 
 Length was measured mid-eye to tail fork (METF) to the nearest millimeter.
 One scale was collected from each chum salmon for ageing.  Scales were
 placed on gum cards that were pressed into acetate sheets. A microfiche
 reader was used to age each readable scale and ages were reported
 following the European notation where the first digit refers to the
 freshwater age not including the year spent in the gravel and the second
 digit refers to the ocean age. Unreadable scales were assigned a code
 depending on the reason they were considered unreadable.
description: Bonanza River escapements from 2018 to 2020 are not considered
 complete counts of chum salmon (or any other salmon species).
 HOBO logger (Onset Computer Corporation) data include time when
 the logger was recording inside and outside air temperature - this
 reflects the time before the logger was placed in the river and after the
 logger was removed from the river but before downloading. 
 In 2019, counting started on June 29 but ceased 4 days later due
 to high water.  Project operations resumed on July 9.