Slender Tuna – Allothunnus fallai – the most elongate of the South Island tuna species
Slender Tuna – Allothunnus fallai
by Gary Wilson
The slender tuna is the most elongate of the South Island tuna species. Specimens generally measure under 1m in length and attain a maximum weight of 12kg although the average is much smaller than this at around 70 – 90cm long and 7 – 9kg in weight.
Colour of Slender Tuna
Blue black above with silvery grey-white flanks although some specimens exhibit a coppery sheen shortly after capture.
Small 2nd dorsal and anal fins and at first glance, it could be mistaken for a small albacore, although a closer look would reveal that it doesn’t have the long sweeping pectoral fins that are so characteristic of an albacore tuna.
The slender tuna is a highly migratory species and it is found right throughout all the southern oceans between 20deg and 50deg South. In New Zealand, it is found in deep waters along the east coast of the
South Island although it occasionally has been known to stray into more warmer waters, with the Bay of Plenty being the most northern end of its range. Incidentally, the current all-tackle world record was taken from these waters a few years ago and at 10.8kg this fish was considered to be a fairly large representative of the species.
Unfortunately, slender tuna, like most of our tuna, are more often than not, taken on gear that does not flatter their fighting abilities and anglers targeting this species are not helped in any way by the fact that slender tuna are generally found in the company of the tackle retailers favourite fish – the barracouta. Schools of surface feeding tuna are a feature in the waters off Dunedin over the late summer months. These schools are usually comprised of a few tightly packed feeding tuna surrounded by literally thousands of ravenous fast moving barracouta and getting a lure through these and into the tuna can be a next to impossible task on lighter tackle, even if one succeeds and manages to place the lure in a position that collects a hook-up extracting the tuna from the school often results in the fish being bitten off as the surrounding barracouta snap at swivels and even the line as it is dragged past.
The keys to catching these ﬁsh consistently are planning and perseverance. The most successful technique seems to be for one angler to position the boat ahead of the approaching school, cutting the motor and allowing the school to come within casting range. Once the ﬁsh are within range the remaining anglers cast to the tuna but unless the cast is accurate the chances of getting the lure back diminish sharply as it is usually swallowed down by one of the hundreds of razor-toothed mouths.
A large supply of small Tobys and slices are a must here. Some terminal tackle may be saved by the addition of a small black wire trace added just above the lure but this in itself is no guarantee that you won’t be cut off. If anything this may actually reduce the number of tuna hooked. Personally, l think mono is the way to go. Apart from casting at sighted schools, slender tuna are occasionally picked up whilst trolling with small weighted plastic squids and hex heads being the answer here.
In areas, further north slender tuna don’t seem to have such a close affiliation with barracouta the same as they do down off Moeraki and the handful of fish so far taken in northern waters have all been boated in areas of upwellings and current movement during the late summer and early autumn months‘
The apparent lack of barracouta traveling with these tuna opens the way for these fish to be targeted on light tackle and it is my prediction that most of the National lighter line class records will come from these waters over the next few years and hopefully once a few more of the details are ironed out on the appearance and movements of these tuna at the more northern end of their range we should hopefully see a few more of these tuna in anglers bags in the near future.