Handling Murray Cod for catch-and releaseEdit
Simon Kaminskas B.App.Sci (Hons) (Env.Sci) Simon is a native fish ecologist who is passionate about catch-and-release fishing for Murray Cod and Murray Cod conservation.
Murray Cod have very soft skin susceptible to damage from poor handling and subsequent infection.
Because of this, Murray cod in the wild suffer seriously from skin diseases and parasites including constant, chronic Lernaea (aka "anchor worm") infections and occasional severe Chilodenella outbreaks. Chronic Lernaea infection create great discomfort and distress for cod and probably kills many more Murray Cod, and is a greater threat to wild stocks, than commonly realised. Chilodenella (a microscopic, single-celled parasite) is usually fatal and has caused several catastrophic cod kills over past decades.
From a fishing perspective, the mortal enemy of Murray Cod, that have been handled roughly, is Saprolegnia fungus. Like almost all diseases affecting our native fish (including the ones mentioned above), Saprolegnia fungus appears to be introduced, courtesy of reckless imports of alien fish species (i.e. trout, carp, redfin) in the 1800s. Saprolegnia fungus is such a problem for Murray Cod hatcheries that, back in the days when Murray Cod were stripped for eggs, broodfish were usually held in a salt bath for several days afterwards to prevent Saprolegnia infection. (Nowadays natural breeding using "Cod Boxes" placed in brood ponds is more common.) Saprolegnia infection is reasonably easy to prevent, but is extremely difficult to stop once it is well-established. Therefore it is a very serious threat. In summary, roughly handled Murray Cod (i.e. slime or skin damaged) are virtually guaranteed to get Saprolegnia infections which at the very least will be seriously detrimental to the cod, and can be fatal. Good techniques must be used to avoid this.
Murray Cod are less hardy and more easily stressed than most native fish, and again, good techniques, including strong tackle and short fighting, handling and photo times, are recommended.
Murray Cod are also larger and heavier than most native fish, and fishermen must be careful not to strain throat and gill ligaments with bad practices such as hanging cod vertically from the mouth or gills.
The following techniques are recommended:
Use strong tackle for short fighting times. Extended fights on light tackle have no place in catch-and-release fishing. Use barbless hooks for easier unhooking and to allow lost cod to eject the lure. Carry a pair of long-nosed pliers for unhooking cod and a pair of strong "tin-snips" to cut through awkwardly placed hook points that cannot be removed, or cannot be removed without causing serious damage.
Do not touch the cod with, or put the cod down on, any hot, dry or rough surfaces. Dry hands, dry shirt fronts (an often overlooked issue), boat gunwales, boat bottoms and/or carpet, river banks (including dry grass, rocks, stumps, gravel), etc. are an absolute no-no. In the unlikely event that a cod needs to be put down on a surface a sopping wet towel is probably best.
DO NOT gaff the cod, even in the jaw.
Do not use an ordinary landing net on the cod under any circumstances. No nets are preferred, but if absolutely necessary, use an Environet which is designed to minimise damage to fish, Do not hang the cod vertically from the jaw, gills or the line/lure. If using lip-grip devices (e.g. "boga-grips") do not use these to hang the cod vertically from these, and be very careful how much pressure you put on the cod's lower jaw with these devices. The pincers on these devices are of a questionable design, being very thin, and concentrate a lot of pressure onto a small area.
Unhook the cod as QUICKLY as possible.
If holding the cod out of the water for a photo, hold it horizontally, with one hand on the jaw and the other hand under the belly, supporting the cod's weight. Be very quick — aim to have the cod out of the water for less than 1 minute; 30 seconds is better. Have the camera ready before you lift the cod out of the water.
Overall, aim to unhook the cod in the water, and touch the cod only with wet hands. This should be easily achievable with most cod. If it is a large cod, get in the water with it. Hold the cod horizontally, supporting their weight. Be extremely quick with photos."
"Thankyou Simon (Goodoo) for putting this piece together for us" (Cheers Allan)