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I. Screw Trap Operations and Maintenance Procedures for Imnaha River Trap
A. Normal Trap Operations
1. Personal safety is always number one. Always wear a life vest and use common sense when on the trap. Never place yourself in a position where you think you could be injured! First Aid kits and trauma packs are located in each vehicle.
2. Read the river gauge and record river levels in the morning at 0800 and evening at 1600 each day.
3. During high spring flows or periods of heavy debris loads a minimum of two people will work the trap for safety reasons. The second person should stay on the shore, positioned with a throw rope, and watch the person on the trap.
4. The normal trap operations schedule is to lower screws on both traps on Sunday afternoon and trap fish daily through Friday morning.
5. Check traps daily by 0800. For safety reasons stand back when opening live box and secure lid.
6. Look for signs of predators (mammals, birds) or dead fish remains on trap or stream banks. If observed, note on data sheets and notify supervisor immediately.
7. Place tree branches or boughs inside the live boxes for hiding cover when age 0 chinook salmon and steelhead trout are being captured. This will reduce predation on fry in the live boxes.
8. Traps should be positioned directly up steam into river flow. Normally the trap should not be moved back and forth. However, during spring high river velocities may require the traps position to be adjusted to reduce water velocity through the screw. The traps positions should be adjusted as follows:
Staff Gauge (m) / Trap Position< 0.90 / Forward
0.90 to 1.0 / Intermediate
1.0 to 1.10 / Rear
>1.10 / Flood Stage Operations
Only one trap will be operated during flood stage operations.
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9. Flow deflectors will be installed in the live boxes at stage heights >0.80 to reduce water velocity in the live boxes.
10. Cover the screens in the bottom of the live boxes at river stage heights >0.90 to reduce turbulence in the live boxes.
11. Check traps as soon as possible during heavy rainstorms and windstorms. River levels, debris loads, and/or fish movements may increase turbidity during spring months regardless of changes in river levels. Be prepared!
B. Emergency Trap Operation Procedures.
1. Live boxes are rapidly filling with smolts:
a. Begin dumping net fulls through remote scanner
b. Place every fifth to tenth net-full into a net-pen
c. Once crisis has subsided work up sub-sampled net-fulls. Record number caught of each species. Scan all chinook and steelhead for PIT-tags.
2. Trap / Live boxes is rapidly filling with debris
a. Remove fish from live boxes into net-pens
b . Raise screw and clear debris from screw and live boxes
c. Lower screw and monitor trap
Note: Debris may be removed without emptying live boxes if no danger to personnel is present and screw does not have to be raised.
3. Screw jammed by debris
Note: This can be the most dangerous situation to occur while operating the trap. Use common sense when this occurs. Severe damage to trap and injuries to personnel may occur depending on river velocities and size of debris jamming the screw. Trap may sink under high water velocities when screw is jammed.
a. Low water velocities
1. Attempt to clear screw first. If unable to quickly clear screw, immediately remove fish from live boxes into net-pens. Raise screw and clear debris.
b. High water velocities
1. Quickly remove fish from live boxes into net pens if possible . If not possible remove fish directly into river
2. Raise screw and clear debris
C. Trap Maintenance
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1. After trap is emptied of fish, raise the screw all the way up and inspect inside of screw for debris and wear. Remove debris as necessary. Check shaft bushings on front and rear of screw and vertical position for wear. Check rubber seals between screw flights and perforated plating. Repair with sealant as needed. Lower the screw when done. Note: Never raise screw up when fish are in the live boxes: they can escape when the screw is raised. Only exception is when personnel are in danger or trap in danger of being lost or damaged (See fish handling protocol for proper handling of fish.
2. Check bolts on both traps for tightness. Tighten as necessary, but don’t over tighten. Check cable clamps and tighten as necessary. Check cables for wear and replace as necessary.
3. Scrub the walkway on pontoons with a long handled brush as needed to prevent algae growth and the possibility of slipping on algae. Also scrub screw and debris drum.
4. Every Monday, grease the two points on the shaft running from the bicycle tire to the debris drum and check the tire for proper inflation.
5. Trap movement should only take place in accordance with specifications in the Normal Trap Operations section (IA.8). Note all trap movements on data sheets and notify supervisor.
6. Make sure tire bumpers are always on the trap to prevent trap from damage on the rocks.
II. Juvenile Fish Handling
A. Setup
1. Prior to set up:
a. Check PIT tag scanner and scale for dead batteries
b. Fill out data sheet headers completely
c. Check the live boxes first. Open the live box lids and observe the number and species of fish in the live boxes. Remove live adult chinook and steelhead immediately and return to the river. Remove and work up any adult mortalities according to carcass sampling guidelines. Remove any excess debris from the trap.
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d. If a large number of adult northern pike minnow, suckers or chiselmouth are in traps, remove immediately, count and record them on the data sheet. Large predatory fish such as northern pike minnow, bull trout, and smallmouth bass should be removed ASAP and scanned for PIT tags. Release adult northern pike minnow, bull trout, smallmouth bass and chislemouth down stream below the bend in the river. Notify supervisor immediately as to their presence.
B. Equipment Set Up
1. Set up the sampling stations with the following equipment:
a. Measuring Board
b. Balance
c. PIT tag scanner
d. Anaesthetic bath and recovery buckets
e. Aerators for anaesthetic bath and recovery buckets
f. Data sheets
g. Scissors
h. Generator and lights (at night)
3. Set up two 5 gallon buckets for recovery of fish, keeping chinook and steelhead separate. Additional buckets may be needed for recovery of recaptured, fin-clipped and tallied fish.
4. Anaesthesia
Note: Chinook salmon and steelhead trout are an endangered species. We want to do everything possible to minimize mortality to juvenile salmon and trout while trapping occurs!
a. Set up anaesthetic bath just before the first group of fish are brought up to sample.
b. Fill plastic tub with water up to the line marked on the inside of the tub (5 gallons). Use a syringe and place 3.0ml of MS-222 stock solution and 2.5ml of Propoly-Aqua in the tub and mix. The dosage of MS-222 for the stock solution is 100g powder/liter of water. Use rubber gloves when working in anaesthetic bath.
c. Initially place no more than 3-5 fish in anaesthetic bath and examine their reaction to the dosage. Look for signs of stress in fish, such as fish immediately going belly-up or rapid trembling. Remove fish immediately to recovery buckets if they exhibit signs of obvious distress.
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e. Place no more than 20 fish in the anaesthetic tub when measuring and fin clipping fish for trap efficiency studies. Place no more than 10 age 0+ chinook (35-60 mm in length) in anaesthetic bath examine closely how quickly they go under the effects of the anaesthetic. If chinook or steelhead become anaesthetized too quickly remove some of the anaesthetic bath water and add fresh water immediately. Place no more than 10 chinook in anaesthetic bath when PIT tagging.
f. If fish do not become anaesthetized in a few minutes add 1 ml of MS- 222 stock. Anaesthetic is inversely related to water temperature, less anesthetic is required at higher water temperatures compared to low water temperatures.
g. Change the anaesthetic bath after every third batch of fish at water temperatures of 5-15 degrees C.
h. At higher water temperatures (>15 degrees C) change anaesthetic bath after every use. Always use discretion if anaesthetic bath needs to be changed more often.
C. Fish Workup
1. Normal Procedures
a. Once the sampling station set up is complete, go to the trap and dipnet fish from the live boxes. Take a 5 gallon bucket (with lid) and dipnets down to the traps. Fill the bucket two-thirds full with water. Remove larger fish from live boxes immediately (bull trout, smallmouth bass, pike minnows, and larger steelhead trout) and place in the bucket and transport the fish to the sampling station for workup. Juveniles are collected next, placing chinook and steelhead in separate buckets, and the data is recorded at the sampling station. After recovery, release large bull trout and other large fish 30-50 meters downstream from the trap location, below the bend in the river. Avoid excess handling of fish. Leave fish in live boxes rather than sitting in buckets waiting to be processed.
b. When dipnetting, avoid “chasing fish” and ramming the dipnet into the corners of the live boxes to catch fish. Instead, slowly move the dipnet and let fish swim up into the water column where you can safely net them. Mortality that occurs in the live boxes often comes from pinching fish with the edge of the dipnet in corners of the live boxes.
c. Measure and record juvenile natural chinook salmon first. Weights and lengths will be collected for all natural chinook salmon. All other species/ first 30 will have lengths and weights recorded. After 30 records, all lengths and every tenth weight are recorded.
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d. Fin-clip the first 300 hatchery chinook salmon for trap efficiency trails during hatchery releases. The first 100 clipped fish will be weighed and measured. The remaining fish will be examined for PIT tags and tallied. The fin-clipping schedule is as follows:
CH-W and CH-H
1) Monday = Top Caudal Clip (TCC)
2) Tuesday = Lower Caudal Clip (LCC)
3) Wednesday = Left Ventral Clip (LVC)
4) Thursday = Right Ventral Clip (RVC)
5) Friday = Left Pectoral Clip (RPC)
6) Saturday = Right Pectoral Clip (RPC)
7) Sunday = Dorsal Clip (DC)
RBT-W*
1) Top Caudal Clip (TCC)
2) Lower Caudal Clip (LCC)
* Alternating Days
e. Allow fin-clipped fish to recover in 5 gallon recovery buckets. Place fin-clipped hatchery chinook salmon and natural chinook salmon into separate net pens in the river. After recovery, juvenile chinook are released at dark to minimize predation (refer to section E; Fish Release). Release all other species into river below trap.
f. Weigh and measure adult pikeminnow, bull trout, and smallmouth bass (always scan for PIT tag presence). Tally all other non-salmonids according to species and distinguish between fry and adult on data sheets.
g. Repeat the dipnetting, measuring and recording process until all fish are removed from the live boxes. Record the time that the live boxes are emptied of fish and take the water temperature.
h. When large numbers of hatchery chinook or hatchery steelhead are trapped, fish will be dipnetted and released into the river to prevent overcrowding in live boxes. If remote PIT tag scanner is available, run all fish through the scanner for PIT tag detection. Subsample the live boxes by placing every fifth to tenth net full of fish into an individually labeled net pen in the river for later sampling.
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2. PIT Tagging Protocol
a. Preparation
1. Prepare anaesthetic bath (see fish anaesthesia section).
2. Sterilize PIT tags for 10 minutes in Ethanol alcohol and air dry.
3. Sterilize the entire hand injector unit (not just the needles) for at least 10 minutes in Ethanol alcohol and air dry.
b. Tagging Guidelines
1. Do not tag at water temperatures above 17 C.
2. Do not tag natural chinook below 65mm in length.
D. Post Handling
1. Make sure headers are filled out on every data sheet.
2. Upon returning to the trailer/office fill out daily forms and charge batteries in the scale and scanners.
3. Perform any needed repairs on equipment (eg. net pens).
4. Dry out equipment, especially scales.
E. Fish Release
1. Fin-clipped fish
a. Check net pens for mortalities.
b. Dipnet the fin-clipped fish from the pens in the river into 5 gallon buckets two-thirds full of water. Place no more than 50 chinook in each bucket. Always keep chinook and steelhead in separate buckets. Release chinook first and steelhead last.
c. Secure bucket lids and transport the fish to the established release point for trap efficiency study. Carry 5 gallon buckets to the rivers edge carefully release fish by submerging buckets.
d. Record release time on data sheet.
2. Non-Fin Clipped Fish
a. All natural and hatchery chinook salmon tagged or tallied are released to the river after dark.
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b. All natural and hatchery steelhead trout tagged or tallied are released to the river after recovery from anaesthetic.
c. Incidental species are either tallied and released directly to the river from the back of the trap or released to the river after recovery from anaesthetic.
3. PIT tagged fish
a. Check net pens for mortalities.
b. PIT tagged fish are to be released directly from the net pen into the river. Record release time and water temperature on data sheets.
F. Mortalities
1. Fin-clipped fish mortalities should be measured and matched up to the original data sheets. Note fin-clipped mortality in remarks.
2. All PIT tag mortalities are measured and scanned, the length and tag number recorded on a data sheet. All site tagged mortalities are cut open and the tag is retrieved. The PIT tag number of site tagged fish is removed from the tagging file prior to validation for The Pacific States Marine Fisheries Commission’s PTAGIS database.
3. All natural chinook and natural steelhead trout mortalities will be placed in zip-lock bags. The bag will be labeled with the date and trap location and stored in coolers at trap site. Upon returning to the trailer, place the mortalities in the freezer.
4. All mortalities (esp. natural chinook) will be recorded daily in the mortality log book. Under the remark section note where the mortality occurred . Use the following categories:
1) Live boxes
2) Anaesthetic bath
3) Net pen prior to handling
4) Net pen (PIT tagged)
5) Net pen (Trap Efficience clip)
G. Carcass Sampling
1. Measure and record the fork length and mid-eye hypural plate length to the nearest millimeter.
2. Determine the sex by cutting the fish open. For female carcasses determine the
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degree of spawning by examining the number of eggs retained in the body and record percent spawned.
3. Record any fin marks. If the carcass has an adipose fin clip cut the snout off
(behind the eye) and place in a snout bag with a snout ID label. Record the snout ID number on the scale card envelope.
4. Check for external and internal tags.
a. Record any tags on the scale envelope and ID label.
b. Place any tags in a snout bag along with the scale card.
5. Take 6-12 scales from the key scale area for each fish. Locate the key scale area on the fish and scrape off all dirt and slime. Using forceps, pluck out 3-6 scales from each side of the fish. Place on a scale card and insert in the scale envelope. Do not overlap scales on the scale card.
6. Cut tail completely off carcass and return to river.
III. Forms
1. Make sure data sheet headers, FPC daily hand log, and summary sheet are filled out completely.
2. Fill out monthly trap summary and monthly trap efficiency form daily.
3. Fill out environmental data form daily.
IV Life at the trailers
1. Keep trailer and dishes clean.
2. Always clean up any Forest Service facilities used.
3. No alcohol at trailers.
4. Always bring any empty gas can, water jugs and propane bottles out with you on Fridays.
5. Keep trailer batteries charged.
6. Do not use toilets or sinks in trailers.
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7. No smoking in trailers.
8. Respect each other’s privacy.
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