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Tracking steelhead migration from the Columbia River through the Pacific Ocean: a proposal. Michelle Rub and Laurie Weitkamp NOAA Fisheries Northwest Fisheries Science Center. The salmon life cycle. Major questions Where do they go (migratory route)?
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Tracking steelhead migration from the Columbia River through the Pacific Ocean: a proposal Michelle Rub and Laurie Weitkamp NOAA Fisheries Northwest Fisheries Science Center
The salmon life cycle • Major questions • Where do they go (migratory route)? • What habitats do they use (temp, depth, prey)? • Are there survival bottlenecks?
Ocean distribution of North American steelhead (1956-2000) “few and far between” Which way do they go? Gritsenko 2002
Why we need to know more about Columbia steelhead ocean residence • Better understand how if or how ocean conditions influence growth and survival • Where and when does it happen? • Determine what “good” ocean conditions are for steelhead • Predict how they might fare with climate change • Changing productivity of California current • Explosion of Humboldt squid
Study Objectives • Determine feasibility of tagging Columbia River steelhead in estuary • Test three acoustic ‘detection systems’ in the North Pacific • Supplement ‘sporadic’ but precise information on geo-position with continuous information on temperature and depth ►Increase our understanding of ocean residence period for Columbia steelhead
Talk outline • Collecting Columbia steelhead • Existing sampling in Columbia estuary • Tagging technology • Acoustic, archival • Listening arrays • Coastal, oceanic, living • Expected results
Collecting juvenile Columbia River steelhead • Existing NWFSC sampling for out-migrating yearling smolts • Sampling at edges of deep channels • Every other week, mid April to late June • 2007-present: caught over 200 steelhead/yr • CWT & PIT tags = fish from throughout basin
Sampling equipment: purse seine • Minimizes injury and descaling to fish • Post-release survival expected to be high • Allows sampling in deep water (far from beach) • Net dimensions: 500 x 35 ft
Pulling it on deck Setting the net Fish in the bunt Pursed net
Steelhead size, 2007-2009 (n = 679) Mean size 214.9 mm FL (range 132-320)
Acoustic Transmitters • 69 kHz • nominal pri interval = 180 sec • (range = 90-270 sec) VEMCO 21mm V7 V9 Goal is to maximize tag life and power output while keeping the weight of the tag to a minimum.
Advantages of acoustic transmitters for this study • can be used to collect precise geo-positional information • information transferred to receiver for collection • Disadvantages of acoustic transmitters • long-lived tags are large/heavy • expensive (~$275 each) • must be ‘heard’
In 2010, there will be three different types of ‘receivers’ operating in the Northern Pacific Ocean with the capability of hearing or detecting VEMCO acoustic tags. • SWFSC towed hydrophone array • The POST project acoustic receiver arrays • SWFSC elephant seal array • *Extensive collection of acoustic receivers in the lower Columbia River and estuary
SWFSC towed hydrophone acoustic surveys from 2008 Red =Aug & Sept Green = Oct & Nov
Detection range: V9 tags ~400-500m V7 tags ~ 200-300m Positions of VEMCO VR2 and VR3 acoustic receiver lines maintained by the Pacific Ocean Shelf Tracking Project (http://www.postcoml.org/)
Photo courtesy of Sean Hayes SWFSC Juvenile elephant seal with a BCT, and an archival tag attached to the animal’s back, and a satellite tag attached to the animal’s head.
Elephant Seal Acoustic Array Image from TOPP- Simmons & Costa
Archival Tags • record temperature and depth • pre-programmed sampling interval from 1/10 sec to 32hrs • Capacity = 32,000 records
Advantages of archival tags • long-lived tag smaller than AT tag • less expensive (~$90-125 each) • large storage capacity • collects a continuous record of temperature and or pressure Disadvantages of archival tags • no precise information on geo-position • must be physically retrieved
Retrieving Archival Tags • stocks originating above Bonneville Dam can potentially be collected in the separation-by-code system • lower river stocks could be collected upon return to the hatchery of origin, from a trap or concrete collection facility • SARs range from ~1-3% for SR steelhead depending on the migration year and origin
Archival tags: 80% >189 mm V7-2L tags: 50% >214 mm V7-3L: 40% >222 mm V9: 7% >259 mm Steelhead size, 2007-2009 (n = 679) Minimum steelhead size by tag Mean size 214.9 mm FL (range 132-320)
Cost • Acoustic Tags ~$275 each x 100 = $27,500 • Archival Tags ~$90 each x 150 = $13,500 • Misc. ~$3,500 • Total = $44,500
Expected results • Determine feasibility of tagging Columbia River steelhead in estuary • Acoustically-tagged steelhead will be “heard” somewhere in the North Pacific • Archival-tagged steelhead will return with temperature record of ocean migration ►Increase our understanding of ocean residence/migration patterns for Columbia steelhead