Parentage-based tagging combined with genetic stock identification is a cost-effective and viable replacement for coded-wire tagging in large-scale assessments of Canadian salmon fisheries

Abstract

I present responses to arguments offered by coded-wire tag (CWT) proponents supposedly limiting the effectiveness of a genetic stock identification (GSI) and parentage-based tagging (PBT) fisheries assessment method. I demonstrate that a GSI-PBT-based assessment method is cheaper, more powerful, and more informative than traditional CWTs. Implementation of a GSI-PBT for Canadian fisheries assessment can provide information at least equivalent to that derived from the current CWT assessment program. Adoption of a GSI-PBT assessment program will facilitate mass-marking of Chinook salmon (Oncorhynchus tshawytscha) in British Columbia, has allowed for genetic tagging during the COVID pandemic while few Chinook salmon juveniles were marked with CWTs, has allowed for tagging of approximately six times more juveniles than traditionally tagged with CWTs, and at an estimated cost of 23 % of that associated with tagging with CWTs. GSI and PBT provide an alternate, cheaper, and more effective method in the assessment and management of Canadian-origin salmon relative to CWTs, and an opportunity for a genetic-based system to replace the current CWT system for salmon assessment. The time has arrived for agencies managing Pacific salmon fisheries to prepare for a transition from CWTs to a genetics-based fisheries assessment program.