Offshore release of salmon smolts

• Main Authors: McNeil, W J, Gowan, R, Severson, R
• Format: Text
• Language: unknown
• Published: ScholarWorks@UMass Amherst 1991
• Subjects: offshore; salmon; smolt; predation; strategy; mortality; releases; Atlantic salmon; Salmo salar; Sweden; coho; chinook; handling; survival; tank; fishing; Norway; Common Murre; Uria aalge; uria
• Online Access: https://scholarworks.umass.edu/fishpassage_conference_proceedings/183

Smolt predation in the vicinity of Yaquina and Coos bays, Oregon, by one bird species, the common murre Uria aalge , appears to be very high. One strategy to reduce mortality of salmon smolts is to transport them in a vehicle for release offshore where predators are less likely to concentrate. Offshore releases of Atlantic salmon Salmo salar in Sweden and Norway yielded consistently higher returns than onshore releases. Preliminary results with offshore release of coho salmon Oncorhynchus kisutch and chinook salmon O. tshawytscha in Oregon are mixed, but handling and transport methods are suspected to play an important role in survival of smolts released offshore. Smolts released offshore from a towed net pen exhibited a much higher return rate than smolts released from a tank aboard a fishing vessel or from a towed barge. Straying was less of a problem when smolts were released from a towed net pen in comparison with a towed barge or deck tank.