From 1996 to 2005 the Rapids video fishwheel site was used to provide fish for the USFWS Rampart Rapids Fall Chum Salmon Tagging Project. In 1997, 1998 and 1999 a fall chum radio-tagging project was conducted by the National Marine Fisheries Service at this site. During the first year of operation the radio tag project became aware of a possible mortality problem with live box held chum salmon. This problem was studied in 1998 and 1999 and project results (not yet published) showed a significant negative effect on fish held in the live box for 4 to 6 hour (J. Eiler, National Marine Fisheries Service, personal communication). Since then a number of studies have been conducted and results published. After this picture of the live box attached to the video fish wheel at Rapids are some of the reports on further research into this issue at Rapids.
Presently the live box at Rapids is only used for rare occasions where lethal sampling is necessary or for the subsistence needs of the operator. All other fish counted by the video project from 2000 to the present have been immediately released back into the river through an open 3’ x 3’ underwater door in the live box.
2007. Residual effects from fish wheel capture and handling of Yukon River fall chum salmon. North American Journal of Fisheries Management 27(3):860-872.
JEFFREY F. BROMAGHIN
U.S. Fish and Wildlife Service, Fisheries and Ecological Services,
1011 East Tudor Road, Anchorage, Alaska 99503, USA
TEVIS J. UNDERWOOD
U.S. Fish and Wildlife Service, Arctic National Wildlife Refuge,
101 12th Avenue, Room 236, Fairbanks, Alaska 99701, USA
RAYMOND F. HANDER
U.S. Fish and Wildlife Service, Fairbanks Fish and Wildlife Field Office,
101 12th Avenue, Room 110, Fairbanks, Alaska 99701, USA
Abstract. (full report see below). - Since 1996, U.S. Fish and Wildlife Service biologists have annually used fish wheels to capture migrating adult fall chum salmon Oncorhynchus keta in the main-stem Yukon River, Alaska, and estimated their abundance via mark–recapture methods. In each year of the study, the mark rate of captured fish at a site near Rampart has been substantially greater than rates observed at numerous locations upriver of that site. The factors most likely to cause the observed reduction in the mark rate are violations of mark–recapture model assumptions or the mortality of marked fish between the Rampart site and upriver locations. Results of studies conducted through 2000 were most consistent with the hypothesis of mortality. We investigate potential explanatory factors for the apparent reduction in mark rates at upriver locations using data collected during additional studies from 2001 to 2003. Results document that holding fish in submerged pens at the marking site negatively affects their ability to migrate for at least some time. No evidence of tag loss or spatial segregation within the mark–recapture study area was observed. A conclusion that some aspect of the capture and handling of fish elevates their mortality upriver of the mark–recapture study area seems well founded. However, holding of fish does not solely explain the reduction in mark rates at upriver locations, and other contributing factors remain unidentified. Researchers using fish wheels should be aware that the gear may be more harmful to fish than was previously thought and may bias estimators of some parameters such as abundance or migration speed.
Open a report for viewing by a left click on the report or download a copy by a right click and then select save target as)
Capture Mortality and Effects Reports
Bromaghin, J. F., T. J. Underwood, and R. F. Hander. 2007. Residual effects from fish wheel capture and handling of Yukon River fall chum salmon. North American Journal of Fisheries Management 27(3):860-872.
North American Journal of Fisheries Management 24:237–243, 2004
Evidence of Handling Mortality of Adult Chum Salmon Caused by Fish Wheel Capture in the Yukon River, Alaska, USFWS, Underwood, Bromaghin, and Klosiewski
An Evaluation of Fall Chum Salmon Mark Rates Upriver of the Rampart Mark recapture Tagging Sites, Yukon River, Alaska,2003. Alaska Fisheries Technical Report Number 76 Fairbanks, Alaska.
Evidence of Residual Effects from the Capture and Handling of Yukon River Fall Chum Salmon in 2002. U.S. Fish and Wildlife Service, Alaska Fisheries Technical Report Number 70 Fairbanks, Alaska.
Evidence of Handling Mortality in Fall Chum Salmon Caused by Fish Wheel Capture on the Yukon River, Alaska. 2002. U.S. Fish and Wildlife Service, Alaska Fisheries Technical Report Number 59 Fairbanks, Alaska.