New paper in the Proceedings of the National Academy of Sciences of the United States

A new paper in the Proceedings of the National Academy of Sciences of the United States reports a landmark study on the migration and survival of Pacific salmon in BC waters.  The report, which will be published the week of 9 May 2011, details the movements and survival of almost 3,500 individual salmon smolts representing four important species of salmon: sockeye, steelhead, coho, and Chinook.   The study is based on the use of a novel large-scale marine telemetry array called POST (Pacific Ocean Shelf Tracking—www.postcoml.org), which is centered in BC coastal waters surrounding Vancouver Island.  The system allowed scientists for the first time to understand the fine-scale migrations of smolts (young salmon) as they leave BC’s rivers and migrate out to sea and, in a ground-breaking advance, to track the same individuals as they migrated back as adults two years later.  The results are based on tracking the movements of individual salmon smolts surgically implanted with uniquely identifiable acoustic tags and using a large array of receivers to detect their passage.

Three major findings are reported in the study:

(1) The first detailed comparison of survival of smolts as they migrate down to the mouth of their rivers, and then as they migrate out of the Strait of Georgia.  This part of the study allowed scientists for the first time to assess the saltwater mortality occurring in the Strait of Georgia, the large body of water lying between Vancouver Island and the BC mainland, and to show how individual populations migrate out of the Strait of Georgia: south through Juan de Fuca Strait or north via Johnstone Strait and Queen Charlotte Strait.  (The majority of salmon migrated via the northern route).

(2) The most interesting finding was for Fraser sockeye, the fish at the center of an intense controversy over the failed 2009 run.  The authors used specially programmed tags that transmitted for two months during the outbound migration in 2007 and then turned off to conserve battery power before turning back on again 2 years later, when the adults returned as part of the disastrous 2009 run.  The authors tracked the round trip migration of the 2 surviving adults (1% of the 200 smolts released) returning in 2009, successfully recording the smolts’ movements out of the Strait of Georgia as they migrated north about 1 week apart in 2007, and then recording their migration back in as adults 2 years later, when both migrated through Juan de Fuca Strait and then up the Fraser River less than 12 hours apart.  This technical breakthrough was of particular importance because it demonstrated that only 1/8th of the total mortality occurred in the Strait of Georgia, and that the remaining 7/8ths of the mortality occurred after passing northern Vancouver Island.  Because only 2 smolts returned as adults, matching the poor survival of the untagged run (1%) the results provide important new data on where the run failure may have occurred, as well as demonstrating the new ability to track salmon throughout their ocean life.

(3) The third finding was that the surgical tagging process did not appear to hurt the smolts after their release; the size at tagging of fish surviving to reach the northern end of Vancouver Island, some 4 to 6 weeks after release in freshwater, was the same as for all the fish released, before mortality took its toll.  This finding is important because one of the initial concerns of many scientists was that smaller fish have poorer survival, either because the tag was a greater burden in little fish or because larger smolts simply had a better chance to survive.   Neither theory was supported by the results.

The study was authored by scientists from Kintama Research Services Ltd., UBC, the Vancouver Aquarium Marine Science Centre, DFO, the BC Ministry of the Environment, and the Seymour Salmon Society.  Kintama is an environmental consultancy that developed the technical design for the array and operates substantial elements of the overall POST telemetry array and is based in Nanaimo, BC.  The Vancouver Aquarium is Canada’s leading non-profit institution for the conservation of aquatic life and hosts both the POST Management Board and the open-access POST database, which makes available all of the data from the POST array.

For further background or media visuals:
Dr David Welch, President, Kintama Research Services Ltd.,
Tel: (250) 729-2600 x223 Cell: (250) 739-9044
david.welch@kintama.com

Animations of BC salmon smolt migrations are available from Kintama’s website:  http://kintama.com/media/videos/

About Kintama: Kintama Research is an award winning environmental consultancy specializing in marine research on the survival of juvenile salmon.  The marine phase of the life history of salmon is the least known aspect of their life history, and knowledge of this phase is critical to the effective management and conservation of North American salmon stocks.  To enable this research, Kintama designed the technical architecture for the prototype POST telemetry array.  As well as conducting a number of key research programs in both the US and Canada using the array, Kintama works closely with POST, operating core components of the current prototype under contract to POST.  Kintama also operates it’s own infrastructure of cross-shelf tracking arrays on the open shelf off Oregon, Washington, British Columbia, and Alaska which it contributes to the POST collaboration.  All data is contributed to the open-access POST database maintained by the Vancouver Aquarium Marine Science Center.  Data from Kintama’s own tagging programs, including this study, are made available for immediate public access through the POST database, waiving the normal one year embargo period of exclusive access.