Geoff Thomas: Put those big ones back

Dry hands have prompted the brown stress marks on this small snapper. Photo / Geoff Thomas

The middle of spring and the middle of autumn are two of the prime times of the year for targeting and catching big snapper. In fact, some impressive fish of 6kg to 8kg have been coming from the 23m mark north of Rakino Island, and some even larger specimens from longlines set off west coast beaches by electric torpedoes.

For keen snapper fishermen, catching a "twenty-pounder" (over 9kg) is a lifetime ambition. Although that was not difficult 20 years ago, the proportion of really big fish in the population has decreased. It is not surprising as they are slow-growing fish. Unlike the fast-swimming kingfish, kahawai, tuna and marlin which may grow to reasonable size in four or five years, bottom-dwellers tend to take much longer. A 9kg snapper may be 30 or even older.

So as big, old men of the snapper world are removed from the sea, it takes a long time to replace them. Which is why it is more common to release such fish today. Commercial fishermen don't want them and will avoid big specimens if they can. The best returns come from fish of around 2kg - and, as their quota is determined by weight, they obviously prefer to bring in larger numbers of small fish. As farmers well know, the best breeders are the big healthy individuals. A farmer doesn't kill his prime bull, and it makes sense for fishermen to put back the biggest fish and take home small eaters. They are called pannies for a reason - think frying pan. The big ones aren't good to eat anyway, and finish up in the smokehouse, or mounted on a board. But a photograph is just as good.

But how a fish is handled makes a big difference to its chances of survival. Fish are not designed to exist out of water, so bright sunshine can damage their eyes and dry hands can damage the coating of slime that protects their skin from infections.

The body is also not designed to support the internal organs, so holding a fish up for the camera with one hand under the throat and the other under the tail is not a good idea. It sags in the middle, and can injure the fish internally. Likewise, holding it by the gills is not great. The filaments are delicate and easily damaged, and the whole weight of the fish hanging from the head end is not how nature intended it to finish up. If a fish has to be held for a photo, using a wet towel is a good start, and

a forearm supporting the stomach is another good idea.

But the best method of releasing your fish is to not remove it from the water. A pair of needle-nosed pliers are good for flicking out the hook. For bigger fish, a spring-loaded grip tool is sold for that purpose. It grasps the lips and you can lift the head out of the water, remove the hook, and slip it back in.

So unless a spectacular catch is needed for a particular purpose such as a competition or for mounting, it makes sense to put the big ones back. It is not only helping the future, but the reverse applies when the largest individuals are removed from

a population. The conservation director of the International Game Fish Association, Jason Schratwieser, said from Florida: "One of the paradigms in fisheries science is looking at the evolutionary effects of fishing pressure on stocks. There is solid evidence on finfish and even lobsters that excessive fishing affects individual size and age of first reproduction. Several studies have shown that heavy fishing pressure targets the largest individuals in

a population. Over time these larger sizes become less abundant and lead to smaller individuals that reproduce at an earlier age."

Nature reacts to pressure by adapting and populations get smaller as individuals mature earlier to spawn, and future generations add to the cycle.

Game fishing is one area where releasing fish is accepted as part of the sport. Fish such as marlin, sharks and kingfish are routinely put back. Kingfish are released by the hundreds, and one angler fishing out of Raglan tagged and released 400 kingfish in one season. Game fish are tagged to track their movements and add to the knowledge which helps administrators of the sport set the rules. But the tagging programme is also aimed at ensuring that a healthy population of each species continues into the future.

So next time a huge snapper surfaces, flick the hook out with pliers and watch it swim away. It's a good feeling.