Eel River Fish Count Station at Van Arsdale Reservoir
2023-2024 Adult Migration Season: May 2024
May 26, 2024
Adult fish migration activity through the fishway at Cape Horn Dam has decreased significantly during May, and as a result, this will be the last update for the 2023/24 season. Over the past three weeks one (1) adult steelhead (female 1, male 0, unknown 0) and two subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The one (1) adult steelhead was observed during the week of May 6 – 12; no adult steelhead were observed during the last two weeks of monitoring. The two subadult steelhead were observed during the week of May 13 – 19 (1 subadult) and May 20 – 26 (1 subadult). The season total for adult upstream migrating steelhead stands at 218 (female 97, male 83, unknown 38). The season total for subadult steelhead stands at 52.
During this same timeframe, 1,162 adult Pacific lampreys were observed ascending over Cape Horn Dam, bringing the season total to 1,827 upstream migrant lampreys.
Andrew Anderson
PG&E | Aquatic Biologist
Van Arsdale reservoir is created by Cape Horn Dam, the first of the two Potter Valley Project dams. The fish counting station here is the oldest in California, and the fish ladder is the longest in the state. Cape Horn Dam was completed in 1908, but the fish ladder and counting station weren’t built until 1922 as part of the licensing for Scott Dam.
The Van Arsdale fish ladder causes “take” of listed species, a violation of the Endangered Species Act. It is often clogged with debris during high flow events, leaves fish vulnerable to predation, and is not designed for the variety of migratory aquatic species that need to pass the dam. Scott and Cape Horn dams block access to hundreds of miles of prime spawning and rearing habitat, and importantly to cold water refugia especially important for summer steelhead.
Removing the dams and allowing the Eel’s native fish to return to its headwaters is the single best recovery action we can take to recover fisheries and restore ecological function throughout the Eel River watershed. As PG&E prepares their license surrender application and decommissioning plan, it is important that Eel River advocates keep up pressure for full dam removal to ensure that the Eel’s wild, native fish have the opportunity for recovery.
Read Dr. Yoshiyama & Moyle’s Historical Review of Eel River Anadromous Salmonids, 2010
Past Weeks
Historic Fish Count Data 1933-2023
May 5, 2024
During the week of April 29 – May 5, no steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead remains at 217 (female 96, male 83, unknown 38). The season total for subadult steelhead remains at 50. During this same timeframe, 330 adult Pacific lampreys were observed ascending over Cape Horn Dam, bringing the season total to 665 upstream migrant lampreys.
April 28, 2024
During the week of April 22 – 28, 1 adult steelhead (female) was observed. The season total for adult steelhead now stands at 217 (female 96, male 83, unknown 38). The season total for subadult steelhead stands at 50. During this same timeframe, 198 adult Pacific lampreys were observed ascending over Cape Horn Dam, bringing the season total to 335 upstream migrant lampreys.
April 21, 2024
During the week of April 15 – 21, 2 adult steelhead (female 1, male 0, unknown 1) and 2 subadults were observed. The season total for adult steelhead now stands at 216 (female 95, male 83, unknown 38). The season total for subadult steelhead now stands at 50. During this same timeframe, 121 adult lamprey were observed moving upstream for a total of 137 upstream migrant lampreys.
April 14, 2024
For the week of April 8 – 14, 5 adult steelhead (female 0, male 3, unknown 2) and 2 subadults were observed. During this same timeframe, the first adult Pacific lamprey returns arrived. A total of 16 adult lamprey were observed moving upstream.
April 7, 2024
During the week of April 1 – 7, 2 adult steelhead (female 0, male 1, unknown 1) were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 209 (female 94, male 80, unknown 35). During this same timeframe, 3 subadults were also observed utilizing the fishway. The season total for subadult steelhead stands at 46.
March 31, 2024
For the week of March 25 – 31, 4 adult steelhead (female 2, male 1, unknown 1) and four (4) subadults were observed moving upstream through the fishway at Cape Horn Dam.
March 24, 2024
During the week of March 18 – 24, 12 adult steelhead (female 2, male 8, unknown 2) were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 203 (female 92, male 78, unknown 33). During this same timeframe, 6 subadults were also observed utilizing the fishway. The season total for subadult steelhead stands at 39.
March 17, 2024
During the week of March 11 – 17, 15 adult steelhead (female 7, male 5, unknown 3) were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead stands at 191 (female 90, male 70, unknown 31). During this same timeframe, 6 subadults were also observed utilizing the fishway. The season total for subadult steelhead stands at 33.
March 10, 2024
During the week of March 4 – 10, 4 adult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 176 (female 83, male 65, unknown 28). During this same timeframe, 3 subadults were also observed utilizing the fishway. The season total for subadult steelhead now stands at 27.
March 3, 2024
During the week of February 26 – March 3, 14 adult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 172 (female 80, male 64, unknown 28). During this same timeframe, 2 subadults were also observed utilizing the fishway. The season total for subadult steelhead now stands at 24.
February 25, 2024
During the week of February 19 – 25, 10 adult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 158 (female 74, male 58, unknown 26). No subadults were observed utilizing the fishway during that time frame. The season total for subadult steelhead stands at 22.
February 18, 2024
For the week of February 12 – 18, 22 adult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 148 (female 70, male 53, unknown 25). No subadults were observed utilizing the fishway during that time frame. The season total for subadult steelhead stands at 22.
February 11, 2024
For the week of February 5 – 11, 28 adult steelhead and 1 subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 126 (female 60, male 44, unknown 22). The season total for subadult steelhead now stands at 22. No Chinook salmon were observed over the same period; the season total for upstream migrating Chinook salmon stands at 255 (female 73, male 72, unknown 21, jack 89). Note a prolonged power outage occurred from just after midnight on Monday, February 5 through the afternoon of Saturday, February 10. The fish monitoring equipment was powered via generator during this time, except for the first three nights of the outage, which resulted in approximately 51.75 hours of video loss during the week.
February 4, 2024
Over the past week, January 29 – February 4, 21 adult steelhead and three 3 subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 98 (female 47, male 34, unknown 17). The season total for subadult steelhead now stands at 21. No Chinook salmon were observed over the same period; the season total for upstream migrating Chinook salmon stands at 255 (female 73, male 72, unknown 21, jack 89).
January 28, 2024
During the week of January 22 – 28, 16 adult steelhead and 4 subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 77 (female 39, male 24, unknown 14). The season total for subadult steelhead stands at 18. No Chinook salmon were observed over the same period; the season total for upstream migrating Chinook salmon stands at 255 (female 73, male 72, unknown 21, jack 89).
January 21, 2024
Over the past week, January 15 – 21, 16 adult steelhead and 2 subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead now stands at 61 (female 30, male 19, unknown 12). The season total for subadult steelhead stands at 14. No Chinook salmon were observed over the same period; the season total for upstream migrating Chinook salmon stands at 255 (female 73, male 72, unknown 21, jack 89).
January 14, 2024
Over the past week, January 8 – 14, 0 Chinook salmon were observed moving through the fishway at Cape Horn Dam. The season total for upstream migrating Chinook salmon stands at 255 (female 73, male 72, unknown 21, jack 89). The Chinook salmon migration season has likely concluded in the Upper Eel River with the last observation at VAFS nearly a month ago. During this same timeframe, 14 adult steelhead and 3 subadult steelhead were observed moving upstream through the fishway at Cape Horn Dam. The season total for adult steelhead stands at 45 (female 22, male 13, unknown 10). The season total for subadult steelhead stands at 12.
January 7, 2024
Over the past week, 12 Steelhead were observed moving upstream through the fishway. The season total for Steelhead stands at 40 (17 Female, 8 Male, 6 Unknown, and 9 Subadult). Over the same timeframe, 0 Chinook were observed moving upstream through the fishway. The season total for Chinook stands at 255 (73 Female, 72 Male, 21 Unknown, and 89 Jack).
December 31, 2023
Over the past week, 17 Steelhead were observed moving upstream through the fishway. The season total for Steelhead stands at 28 (12 Female, 5 Male, 5 Unknown, and 6 Subadult). Over the same timeframe, 0 Chinook were observed moving upstream through the fishway. The season total for Chinook stands at 255 (73 Female, 72 Male, 21 Unknown, and 89 Jack).
December 24, 2023
The first Steelhead of the season was observed migrating upstream at the Van Arsdale Fish Station during the week of December 24, 2023. Over the past week, 11 Steelhead were observed moving upstream through the fishway. The season total for Steelhead stands at 11 (4 Female, 1 Male, 2 Unknown, and 4 Subadult). Over the same timeframe, 2 Chinook were observed moving upstream through the fishway. The season total for Chinook stands at 255 (73 Female, 72 Male, 21 Unknown, and 89 Jack).
December 17, 2023
Over the past week, 3 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 253 (73 Female, 71 Male, 21 Unknown, and 88 Jack).
December 10, 2023
Over the past week, 61 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 250 (72 Female, 70 Male, 20 Unknown, and 88 Jack).
December 3, 2023
Over the past week, 16 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 189 (58 Female, 48 Male, 15 Unknown, and 68 Jack).
November 26, 2023
Over the past week, 62 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 173 (54 Female, 41 Male, 13 Unknown, and 65 Jack).
November 19, 2023
Over the past week, 95 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 111 (29 Female, 23 Male, 9 Unknown, and 50 Jack).
November 12, 2023
Over the past week, 10 Chinook salmon were observed moving upstream though the fishway. The season total for Chinook stands at 16 (2 Female, 1 Male, 2 Unknown, and 11 Jack).
November 5, 2023
The first Chinook salmon of the season was observed migrating upstream at the Van Arsdale Fish Station on October 24, 2023. Over the past two weeks, 6 Chinook salmon were observed moving upstream through the fishway. The season total for Chinook stands at 6 (1 Female, 0 Male, 1 Unknown, and 4 Jack).