Slide thicknesses for different types of fish scales

0.50 mm (0.020”) = Trout, salmon, tullibee
0.76 mm (0.030”) = Young fish – many species
1.00 mm (0.040”) = Bass, walleye, perch, sucker, sunfish
1.50 mm (0.060”) = Carp

Tips for taking scale samples:
Age determination of fish is easy if you are consistent. Take scale samples from a specific part of each fish. (a) On spiny-rayed fish, just below the lateral line and below the middle of the spiny dorsal fin. (b) For most soft-rayed fishes, the area between the lateral line and dorsal fin. (c) For trout, the area directly below the lateral line beneath the posterior end of the dorsal fin is best.

Materials used in Wildco Van Dorn bottles

Metal parts are 304 or 316 stainless steel and are rugged, durable and lack contaminating organics. Nonmetals are flexible, blue polyurethane; rigid, white ASA plastic with silicone gasket; transparent acrylic; and opaque PVC. Internal parts are nonmetallic. Plastic samplers may use some external metal parts for durability and rigidity.

Alpha™ seal – Blue, flexible polyurethane that can leach and contaminate samples. Because it may leach slight traces of mercury and phosphorous (among other potential contaminants), do not use for trace metal or chemical sampling. Durable, long lasting and flexible.

Beta™ seal – White, rigid inert ASA plastic with a silicone gasket specifically for trace metal sampling. It does not leach mercury but is not as durable.

Maintenance Tips for Wildco Core Samplers

Cleaning Wildco® corer valves:

Keep valves and seats in corer heads free of dirt, grease and oil to maintain a good air seal. It’s best to clean valve and seat after each sample with 70% ethyl alcohol.

Chemical removal of rust stains from stainless steel:

Stainless steel parts may show a rust stain, indicating an active corrosion cell area which should be deactivated. These are often caused by scratching or marring the surface.
Soak the stained area in concentrated HNO3 for a few hours or make a paste to spread over the stain using Vaseline, corn starch or other thickener. Repeat as needed.
Sand blasting with clean silica sand will remove rust but must be rinsed with strong HNO3 to prevent future damage.
If left in salt water, stainless steel corrodes quickly. All stainless steel should be rinsed at once with fresh water after removal from salt water.

How to Use Whirl-Pak Bags

1. Tear off top of bag along perforation
2. Use pull tabs to open
3. Place sample in bag
4. Hold bag by wire ends and whirl 3x to close
5. Bend wire ends onto bag

How to use Ward Counting Wheel

1. Place under a binocular dissection microscope in such a way that the groove is directly under the object lens.
2. Place a 5 to 10 mL sample in the trough.
3. The sample channel has a small plastic divider placed across the groove at one point to mark the start and finish of the count.
4. The plankton are counted as the wheel is rotated.
5. To maintain, wash with mild soap and soft water. Rinse completely with distilled water before drying. To remove surface scratches, buff gently with mild abrasive and soft flannel buffer, then wash as directed.

How to Use Sludge Judge:

1 Lower to the bottom of the tank
2 Float valve opens, allowing liquid to flow in. When filled to the surface level, tug slightly on the line as the unit is raised.
3 This sets the check valve, trapping the mixture inside
4 Read the amount of solids in the sample using the 1’ increments marked on the sections.
5 To release, touch the pin extending from the bottom section against a hard surface. This opens the valve to drain the sample.

How to use Sedgewick Rafter Counting Cells

1. Check length and depth of your cell before use.
2. Fill cell with your sample using Hensen-Stempel pipettes.
3. Before counting, let it stand for at least 15 minutes to settle plankton. Count plankton on bottom of cell.
4. Calculate as per Standard Methods.

How To Use Schindler-Patalas

1. Lower into water. Hinged doors open as water and plankton flow through.
2. Pull the line, trapping plankton at known depth.
3. Both doors seal against urethane gaskets to prevent loss of sample.
4. Raise above surface to collect contents in bucket.

How to use messengers

1. Run line through messenger so tapered end points toward lower line end.
2. Run line through hole in trip release and knot securely under the handle.
3. Attach line to bottle, calibrate if desired.
4. Set stoppers in position. Pull them out of bottle end and attach cable loop to pin. When cables are attached, lower slowly, counting marks.
5. Hold messenger to keep it from falling down the line before you are ready.
6. When the bottle is at desired depth, drop the messenger, tapered nose first, to strike the trip release pad.

How To Use General Oceanics Flowmeter

1. Record the reading and time before and after sampling.
2. Subtract first reading from the second to determine average speed over sampling time.