Coho face high mortality after catch and release:
- Anglers should avoid over-handling salmon
- Use gaff release to minimize injury
Coho appear more likely to die from injuries sustained in recreational fisheries than other Pacific salmon species, according to a UBC-led study.
The two-year study tagged and tracked coho salmon caught in recreational fisheries and subsequently released. So-called catch and release fishing is used as a conservation tool to protect species of concern, with the assumption that released salmon live and reproduce in high numbers.
Gathering evidence that C&R works is difficult and many estimates are generated from lab-based studies rather than in the wild. This study required that the coho travelling back to their natal streams were caught by anglers associated with the researchers and released after having an acoustic transmitter attached behind the dorsal fin. The researchers collected data about the condition of the fish, injuries from fishing gear, and air exposure.
The tagged coho were then tracked by an array of acoustic receivers placed in multiple locations from Puget Sound to the Juan de Fuca Strait and the Fraser River.
More than 31 per cent of the tagged coho died within 50 km of their release location.
Researchers led by Emma L Lunzmann-Cooke, reported: “Scale loss, eye damage, bleeding, and smaller body size of coho salmon were associated with increased odds of mortality. Scale loss and smaller body size were also associated with slower migration rate post-release.”
Coho mortality appears to be considerably higher than estimates of C&R-related mortality used in coho fisheries management, and higher than estimates for other Pacific salmon species.
To minimize the risk of mortality from C&R, try to identify the species of salmon on your line before bringing it out of the water. If you intend to release the fish, use the gaff release method to remove the hook.
Review the gaff method with this video by Brendan from Reel West Coast & Martin Paish from the Sport Fishing Institute of British Columbia: