Is it time to rethink the use of hatcheries to produce Pacific salmon in the Strait of Georgia?
Streaming Media
Presentation Abstract
All Pacific salmon hatcheries produce salmon, but the original hypothesis in the 1970s was that hatchery-produced salmon would fill unused ocean production capacity and the Canadian commercial catch of about 70,000 MT would double to about 140,000 MT by 2005. In 2019 and 2020 the averaged total Canadian commercial Pacific salmon catch for these two years was 5,237 MT. The science is clear that there was not unused ocean carrying capacity and the original hypothesis that more juveniles needed to be added to the ocean to produce more salmon can be rejected. It is the capacity of the ocean in recent years that was regulating abundance and not a shortage of smolts or fry. We found in a recent 9-year study that a 51% reduction in hatchery released coho salmon into the Strait of Georgia did not reduce the number juvenile hatchery coho salmon in the fall of the first ocean year showing that the trend in the percent of hatchery and wild juveniles after four months in the ocean did not change over the 9-years. One explanation is that the hatchery-reared coho salmon had adapted to climate related changes in the Strait of Georgia ecosystem at a critical survival time in the first months in the ocean, perhaps even better than wild salmon. Our example is for coho salmon but it is possible that the example extends to other species of salmon. The message is that, 1- we need to understand better the mechanisms that regulate coho salmon in the ocean and 2 – we need to rethink how we use hatcheries.
Session Title
Data Science 3
Conference Track
SSE1: Science for the Future
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-traditionals-240
Start Date
28-4-2022 10:15 AM
End Date
28-4-2022 11:45 AM
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Subjects – Topical (LCSH)
Pacific salmon--Georgia, Strait of (B.C. and Wash.); Fish hatcheries--Georgia, Strait of (B.C. and Wash.); Fish stock assessment--Georgia, Strait of (B.C. and Wash.)
Geographic Coverage
Georgia, Strait of (B.C. and Wash.)
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Format
application/pdf
Is it time to rethink the use of hatcheries to produce Pacific salmon in the Strait of Georgia?
All Pacific salmon hatcheries produce salmon, but the original hypothesis in the 1970s was that hatchery-produced salmon would fill unused ocean production capacity and the Canadian commercial catch of about 70,000 MT would double to about 140,000 MT by 2005. In 2019 and 2020 the averaged total Canadian commercial Pacific salmon catch for these two years was 5,237 MT. The science is clear that there was not unused ocean carrying capacity and the original hypothesis that more juveniles needed to be added to the ocean to produce more salmon can be rejected. It is the capacity of the ocean in recent years that was regulating abundance and not a shortage of smolts or fry. We found in a recent 9-year study that a 51% reduction in hatchery released coho salmon into the Strait of Georgia did not reduce the number juvenile hatchery coho salmon in the fall of the first ocean year showing that the trend in the percent of hatchery and wild juveniles after four months in the ocean did not change over the 9-years. One explanation is that the hatchery-reared coho salmon had adapted to climate related changes in the Strait of Georgia ecosystem at a critical survival time in the first months in the ocean, perhaps even better than wild salmon. Our example is for coho salmon but it is possible that the example extends to other species of salmon. The message is that, 1- we need to understand better the mechanisms that regulate coho salmon in the ocean and 2 – we need to rethink how we use hatcheries.
