It is any device such as a
thin fillet knife, ice pick, a hypodermic syringe w/ needle etc. It is use to slide under the scales of the fish a puncture the air bladder to release the air. When fish are brought to the surface fair fast, the air bladder blows up, eyes bulge out etc. After the air bladder deflates, it can go back into the water with hopes to survive. The ones offered are hypodermic syringes with needles .
Venting tool: A venting tool is a device capable of penetrating the abdomen of a fish in
order to release the excess gases accumulated in body cavity when a fish is retrieved from
depth. A venting tool must be a sharpened, hollow instrument, such as a hypodermic
syringe with the plunger removed, or a 16–gauge needle fixed to a handle. A larger gauge
needle is preferred in order to allow more air to escape rapidly.
A device that is not
hollow, such as a knife or ice pick, is not a venting tool and will cause additional damage.