Northwest Marine Technology makes three Coded Wire Tag injectors:
Mark IV Tag Injector and Quality Control Device (QCD)
This is the workhorse of Coded Wire Tag injection and uses spools of wire. The Mark IV Tag Injector can be used to inject up to 600-800 tags/hour and is designed for projects with many thousands of fish to tag. It cuts a tag from the spool and injects it into the specimen. The Mark IV Tag Injector can inject half length (0.5 mm), standard length (1.1 mm), one and a half length (1.6 mm) or double length (2.2 mm) tags. It can be used with either a Head Mold to position the specimen or a needle support tube for freehand tagging.
The Quality Control Device (QCD) is used with the Mark IV to verify that a tag has been injected. The fish is dropped into the QCD after tagging, and fish with a tag will be diverted from those without a tag. The Mark IV can be used without a QCD, but the QCD requires a Mark IV to operate.
Handheld Multishot Injector
The Handheld Multishot Injector can be used to achieve tagging rates of several hundred tags per hour, and is suitable for moderate sized projects or when power is not available. The Multishot cuts a tag from the spool of wire and injects it into the specimen. The Multishot can inject standard length (1.1 mm), one and a half length (1.6 mm) or double length (2.2 mm) tags. It can not be used to inject half length tags. Like the Mark IV Injector, the Multishot can be used with Head Molds to assist with tag placement.
Single Shot Tag Injector
The Single Shot Injector is used with Precut Sequential Coded Wire Tags. It is suitable for smaller-scale tagging projects in which a couple of hundred tags may be injected in a day. Precut Tags are loaded into a hollow needle and a spring-loaded plunger is used to push the tag into the specimen.
Selecting Needles for the Mark IV and Multishot
As you prepare for tagging, you will need to select Coded Wire Tag injection needles. A clean, sharp needle of the proper length and style is necessary for effective tagging. The type of injector, the species, and the size of the fish, and the target tag location will determine the appropriate needle.
Mark IV Coded Wire Tag Injectors use 2.5 inch (6.35 cm) and 3.5 (8.9 cm) injection needles. The shorter needle is for use with head molds. The longer needle is for use with the needle support tube.
Multishot Injectors use a 1.55 inch (3.94 cm) Coded Wire Tag injection needle. This needle can accommodate a head mold or a needle support tube.
Each of the three Coded Wire Tag injection needles is available as either “non-etched” (pictured on the left) or “etched” (pictured on the right). A non-etched needle has a constant outside diameter (0.0225 in, 0.57 mm) from its base all the way to the beginning of the beveled tip. The etched needle is reduced to a smaller outside diameter (0.0185 inch, 0.47 mm) for about 0.3 inches (0.76 cm) from the beginning of the bevel.
The etched needle has a greater likelihood of bending with fish with tougher tissue and with “body” tagging such as cheeks of smallmouth bass, the scutes of sturgeon, and the rostrum of paddlefish. The non-etched needle in a needle support tube is often the better combination for penetration and tag placement in these types of tagging.