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Methods to Mitigate Tagging Effects (Actual & Perceived) Scott McCutcheon Ryan Richmond Methods to Mitigate Tagging Effects.

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Presentation on theme: "Methods to Mitigate Tagging Effects (Actual & Perceived) Scott McCutcheon Ryan Richmond Methods to Mitigate Tagging Effects."— Presentation transcript:

1 Methods to Mitigate Tagging Effects (Actual & Perceived) Scott McCutcheon Ryan Richmond Methods to Mitigate Tagging Effects

2 Acknowledgements Comparing Preloaded Single Use Injectors to Multiple Use Injectors Contributed data: Doug Marsh, NMFS Nate Wiese, USFWS Hagerman NFH Tom Kahler, Douglas County PUD

3 Goal Methods to Mitigate Tagging Effects Take away question: – If a study is conducted with better methods and material, will the results be significantly different?

4 Introduction Methods to Mitigate Tagging Effects PIT tags give us the ability to tag a smaller but significant portion of a population while allowing us to monitor individuals. Since we have the ability to monitor individuals, it is imperative that we: Use methods material that will give the fish the greatest chance of survival. And, use methods and material that accurately account for all tags at release and return.

5 Scope Methods to Mitigate Tagging Effects During this presentation I will: 1.Define what “Tag Effects” are. 2.Then list some of the causes and effects. 3.And, finally I will list some preventative measures With examples

6 What are Tagging Effects? Methods to Mitigate Tagging Effects What are tagging effects that reduce your data quality or fish quality and survival? 1.Reduced growth 2.Decreased survival 3.Lost data 1.Tag shedding Tag shedding post release Unaccounted tag shedding prior to release 2.Tagged fish mortality Mortality post release Unaccounted mortality prior to release 3.Misplaced data Post tagging lost data files or tags 4.Unread tags Unread tags during release Unread tags during adult return Are these anomalies actual “Tag Effects” or improper methods and material that are perceived to be tag effects?

7 Discussion of Tag Effects Methods to Mitigate Tagging Effects I will now discuss each Tag Effect in detail. Beginning with Reduced Growth

8 Tagging Effects that may reduced growth Methods to Mitigate Tagging Effects What is the end result of reduced growth? a)Smaller juveniles fish - more susceptible to predation. b)Smaller adults - may result in lower fecundity.  Was the difference significant?  Did you examine the growth of the individual?

9 Reduced Growth Methods to Mitigate Tagging Effects What tagging related problems lead to reduced growth? 1.Tag wound Why? The body is repairing itself rather than building body mass. Prevention Sharp needles Training Photo provided by: Nate Wiese, USFWS Hagerman NFH

10 Reduced Growth Methods to Mitigate Tagging Effects What tagging related problems might lead to reduced growth? 1.Tag wound 2.Tag size Depending on the size of the fish Tag may take space that can be used for: food storage fat reserves. Prevention Use smaller tags with small fish when ever possible Use 12mm tags with fish > 65mm Use 9mm tags with fish < 65mm

11 Decreased Survival Methods to Mitigate Tagging Effects What tagging related problems might decrease survival? 1.Tag wound Why? Entry point for infection Punctured organs Puncture gut without killing the fish (shed tag) Cause? Dull needles Deep insertion Tagging angle Prevention Training Use sharp needles Single Use Injector Proper angle Proper location

12 Decreased Survival Methods to Mitigate Tagging Effects What tagging related problems might decrease survival? 1.Tag wound 2.Double Marking o Studies have shown decreased survival Does PIT or CWT lower survival or is it double stress? o Prevention Avoid Avoiding double marking studies is not practical and not recommended. Allow recovery between tagging events and prior to release

13 Decreased Survival Methods to Mitigate Tagging Effects What tagging related problems might decreased survival? 1.Tag wound 2.Double Marking 3.Improper Handling during tagging o Cause Too long in the anesthetic Too many fish in the net (O2 depletion within the net) o Prevention Training Do not put more fish in the net than can be tagged in a safe amount of time Example of over crowded net

14 Decreased Survival Methods to Mitigate Tagging Effects What tagging related problems might decrease survival? 1.Tag wound 2.Double Marking 3.Improper Handling during tagging 4.Tagging unhealthy fish o Effect Higher pre release mortality And/or, higher post release mortality o Prevention Only tag healthy fish

15 Data Loss Methods to Mitigate Tagging Effects 1.What is the cause of Data Loss? 1.Tags lost during tagging Broken tags Non-functional tags Lost tags o Effect to Project o Reduction in number of fish tagged o Prevention Training Needle bevel should by against the fish to avoid tags not entering the fish (example: incorrect method) Account for all missing tags Count Collect

16 Data Loss Methods to Mitigate Tagging Effects 1.What is the cause of Data Loss? 1.Tags lost during tagging 2.Tags shed prior to release o Cause Improper tagging methods Dull needle Excessive movement immediately after tagging. o Prevention Training Only use sharp needles Whenever possible, hold fish in a calm after tagging Search for shed tags in the holding facility

17 Mortalities and shed tags collected by week during 10 weeks of yearling Chinook holding at Wells Hatchery, Comparing Preloaded Single Use Injectors to Multiple Use Injectors Total tagged = 80,487 shedding = 127 (0.16%) mortality = 380 (0.47%) (Most shedding occurs in the first 7 days post tagging. The tags collected later are presumed to be tag consumed and later passed by other fish. This theory is supported by the USFWS study at Hagerman NFH, ID.) (Tag consumption varies by species and age of fish.)

18 Tag seeding evaluation of Steelhead Comparing Preloaded Single Use Injectors to Multiple Use Injectors The USFWS at Hagerman NFH tested their shed recovery efficiency in December – By placing twenty-five tags into 4 raceways via a standpipe (so they were not ingested while falling into the raceways). – Four days later, a blind routine magnetic sweeping of the raceways yielded zero tags. – After the blind sweeping, they returned to the four experimental raceways and re-swept them with magnets and inspected likely areas for shed tags. These additional efforts recovered zero PIT tags. – However, 46% of these PIT tags were detected when the fish were pumped through a PIT tag array. – USFWS hypothesized: Loose PIT tags were ingested and lodged in the intestinal tract. Some of the ingested tags may have occurred in already tagged smolts or smolts that ingested multiple tags effectively cancelling both PIT tags. Ingestion could explain the lack of shed tag recoveries and some of the lower detection rate.

19 Data Loss Methods to Mitigate Tagging Effects 1.What is the cause of Data Loss? 1.Tags lost during tagging 2.Tags shed prior to release 3.Tags are not detected during release monitoring o Cause Unaccounted shed tags Tag collision Tag orientation o Prevention Collect shed tags consistently during the holding period Use multiple release monitors Use only fish detected during releases.

20 Example of Release Monitors At Rapid River Methods to Mitigate Tagging Effects Monitors installed at raceway exit. Used when: A portion of the population is tagged. Fish are released directly from raceway or pond. Most effective when fish are allowed to volitionally exit over several weeks.

21 Example of Release Monitors At Chewuch Acclamation Site Methods to Mitigate Tagging Effects Installed at the raceway exit Single read system Two antenna to spread out fish Driven by FS2001 readers

22 Example of Release Monitors Truck Loading at Turtle Rock Methods to Mitigate Tagging Effects Used when: Small portions of a large population of PIT tagged fish is released at different locations. (Each truck load has a different release file.) 4 FS2001 readers (1 on intake and 3 on exit pipe) Avoid tag collision by not over crowding.

23 Data Loss Methods to Mitigate Tagging Effects 1.What is the cause of tags not being read? 1.Tags lost during tagging 2.Tags shed prior to release 3.Tags are missed during release monitoring 4.Tags are not detected during adult return monitoring Cause Monitoring fish using hand held readers Prevention Monitor fish using stationary monitor systems Examples: IDFG, Sawtooth and South Fork Traps: 10 to 30% of fish detected by the stationary monitor system were missed by hand held readers. NMFS at Lower Granite: 18% of the fish detected by stationary monitor systems were missed by hand held readers.

24 Examples of Adult monitor systems Methods to Mitigate Tagging Effects The following series of slides show examples of adult monitor systems used in the Columbia basin.

25 Adult Monitor Sawtooth Hatchery Trap Methods to Mitigate Tagging Effects Stationary readers demonstrated 30% greater detection efficiency than hand held readers.

26 Adult Monitor South Fork Salmon River Trap Methods to Mitigate Tagging Effects Stationary readers demonstrated 10 to 12% greater detection efficiency than hand held readers.

27 Adult Monitor System Dworshak NFH Methods to Mitigate Tagging Effects

28 Adult Monitor System Gumboot Weir on the Imnaha River Methods to Mitigate Tagging Effects

29 Adult Monitor Leavenworth NFH Methods to Mitigate Tagging Effects

30 Adult Monitor Ladder monitor at Priest Rapids Methods to Mitigate Tagging Effects

31 Recommendations Comparing Preloaded Single Use Injectors to Multiple Use Injectors I recommend: 1.Use properly trained personnel 2.Whenever possible, hold fish post tagging for wound recovery (2 weeks) 3.Use 9mm tags when tagging fish < 65mm 4.Use only sharp needles If using MUI – limit their use to < 10 times Or, use SUI 5.Account for all tags And/or 6.Use monitors during juvenile releases Only use data from fish detected at time of release. 7.Monitor adult returns with stationary monitors

32 Questions Comparing Preloaded Single Use Injectors to Multiple Use Injectors Contact: Scott McCutcheon or Ryan Richmond At: Biomark, Inc. 703 S. Americana Blvd. Suite 150 Boise Idaho (208)


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