The Data Wars Of the Columbia Basin

Adipose Fin Clip Steelhead with Adipose Fin Steelhead without Adipose Fin

Issues with Adipose Fin Clips Hatchery = Clipped Wild = Not Clipped In Hanford Reach = Wild can be Clipped In Snake River = Hatchery can be not Clipped Below McNary Dam = Can only determine Clipped and Unclipped, (not hatchery and wild)

Coded Wire Tags (CWTs) Unclipped hatchery fish are treated as wild fish in the Lower Columbia River Directives for 100% marking of hatchery fish can be achieved by using CWTs for hatchery fish. A CWT detector can detect the presence or absence of CWTs. The fish must be dead in order to read the CWT to connect it with a particular hatchery release or stock and brood year. Regional Mark Processing Center (RMPC) is a central database of CWTs, all parties have access to the same data.

Freeze Brands Authors: McCutcheon and Georgi An assessment of PIT tag and Freeze Brand Recovery Data for Juvenile Salmonids at McNary Dam, 1988 This study evaluated mark recovery data from PIT -tagged and freeze-branded river-run yearling and subyearling chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O. nerka), and steelhead (O. mykiss) at McNary Dam in 1988. Double-marked (PIT-tagged and freeze-branded) juvenile salmonids were released within the McNary Dam collection system upstream from the PIT -tag detectors and brand sampling system. Results indicate that brands were recovered in smaller proportions than PIT tags and the variability of brand data was considerable. Most of the error associated with brands was attributable to human error inherent in brand detection and interpretation.

Visual Implant Elastomer Tags (VIE) Visual Implant Elastomer Tags are good for some uses (hatchery to hatchery, etc.) Limited colors available (Red, Yellow, Orange, Pink, Green, Blue) Limited locations available (left eye, right eye) No coordinating body responsible for VIE tags across the Columbia Basin. Thus, when observed at mainstem dams, or in ocean, tags can be from multiple origins. Tag duplication is common between agencies and tribes.

PIT Tags Passive Integrated Transponder Tags Centralized database, named PTAGIS. The same data sets are available to all parties. Individual fish can be tracked from smolt to adult life stages. Tag can be read without killing the fish, by a PIT tag detector. Tagging cost is about $5 per fish, including labor. Extensive antenna and detector systems across Columbia Basin can be used by all parties. Large data sets can be generated at reasonable cost, detector redundancy provides some assurance that misreads are a low probability event.

PIT Tag Analyses Data Sets can be large enough to provide reasonable confidence intervals for Smolt to Adult Return Ratios (SARs), and for Reach Survivals. Analyses using parametric methods to calculate confidence intervals often assume a normal distribution (usually gaussian). Confidence intervals are therefore symmetric. Analyses using bootstrapping methods to calculate confidence intervals do not assume a distribution, but determine the distribution from the actual data set. Confidence intervals can therefore be asymmetric. Recent tag loss and mortality studies suggest that survival calculations are biased high.

PIT, Radio, and Acoustic Tags PIT Tags have certain limitations Radio and Acoustic Tags address those limitations Ocean is too large to cover with PIT tag detectors PIT tags are not useful for determining approach routes to and exit routes from mainstem dams in water column. PIT tags are not very useful for determining which pools and areas under ice are being used for overwintering. On the other hand: PIT tags have no batteries, and are cheaper. Acoustic detectors can cover a large area of the Ocean Radio tags and acoustic tags are much more useful for determined approach routes to and exit routes from mainstem dams in water column. Radio tags are much more useful for determining what pools and areas under ice are being used for overwintering. On the other hand: Radio and acoustic tags have a limited battery life, and are more expensive.

Tag Data Analysis If you can demonstrate that confidence intervals for any given parameter are different than a study shows, you’ve cast doubt on that study. If you can show that the average value for a parameter is different than a study shows, you’ve cast doubt on that study. If you can show that assumptions which are not necessary have resulted in bias, you’ve cast doubt on that study. PIT Tags, and CWTs have same data sets available to all parties. Data sets from fin clips, VIEs, Freeze Brands, Radio Tags, and Acoustic Tags may not be available to all parties. Management decisions in the Columbia Basin do not depend on data sets that are not available to all parties.