Tunas of New Zealand’s South Island – Four species of interest by Gary Wilson
There are ten different tunas available around New Zealand
Tunas are one of the most exciting species to fish catch. Irrespective of their size they are fast, hard, dogged fighters who apart from their excellent fighting abilities are eagerly sorted worldwide as a top class food fish.
Here is New Zealand we are blessed with an abundance of tuna species with no less than 10 different species available for the ardent angler. These range from the massive bluefin of 180kgs, or more, right down to the smallest representative of the family, the frigate tuna (frigate mackerel) with a weight averaging only a few kilos.
As a family, tuna, are basically uniform in body construction, with only one or two exceptions they are generally sleek and streamlined, with a well-developed body that gradually tapers to a narrow point just before the tail. On each side of the tail and slightly forward of it, they are a couple of bony keels that provide an improved flow of water to the tuna’s main power source – its deep forked and heavily muscled tail.
Tunas are built for speed
Every aspect of a tuna is built for speed and stamina. It’s the whole body is designed to minimise drag and to this end, it has evolved eyes that sit flush with the skin’s surface and special grooves in the body that accommodate it’s dorsal, pectoral and sometimes pelvic fins whilst not in use.
Another adaptation the tuna has made to suit its pelagic lifestyle is its vascular system which is highly developed and helps keep the tuna’s body temperature several degrees warmer than the surrounding water. This adaptation aids the tuna by increasing the working speed and power output of the muscles enabling tuna to use their muscles several times faster than a normal fish could.
What all this adds up to from an angler’s point of view is a fish that is pure dynamite on the end of a line with sustained speed, stubborn resistance and long drawn out fights being a real feature of a scrap with a decent tuna.
Of the range of tunas in New Zealand waters only four species are of interest to the angler fishing around local coastlines and these are the albacore, bluefin, slender and butterfly tuna, all of which are present in our waters for least several months of the year.