Tuna are a wary, powerful pelagic that hold iconic status in the spearfishing community. While sightings are reasonably frequent off the WA coast, these fish are an uncommon catch even for the state’s most experienced divers.
The three most commonly encountered species are Yellowfin, Southern Bluefin and Longtail or Northern Bluefin Tuna. Yellowfin have the biggest range (pretty much all of WA). Southern Bluefin are found from the SA boarder, ranging north to Shark Bay. Northern Bluefin are particularly common from Exmouth to the NT boarder but have been recorded as far south as Busselton.
The legendary Dogtooth Tuna are generally restricted to far offshore atolls although there have been rare sightings in deep water from Exmouth to the Monte Bello Islands.
Tuna are excellent eating, particularly are sushi or as 1cm thick steaks cooked slightly rare with lemon pepper. It can almost be treated as pork, and a large chunk of tuna actually makes an excellent roast with flavoured rice stuffing.
As tuna meat has a very high blood content the fish should be given a quick spike to the brain followed by bleeding and gutting before placing in a seawater / ice slurry. All red meat and skin should be removed before freezing to preserve its eating quality.
There is no minimum size limit for Tuna in WA waters although there are individual bag limits of 3 fish for Yellowfin, Southern Bluefin, Longtail, Dogtooth, Skipjack, Mack and Bigeye. However these species are all part of the "Large Pelagic Finfish " group so remember you may only take a combination of 3 fish from the entire Large Pelagic Finfish list per day and this applies statewide.
For current information please refer to:
All other Tuna species fall into "Nearshore" and have a daily bag limit of 8
Characteristics and habitat
Yellowfin are easily recognised by their long pectoral fins and bright yellow dorsal and anal fins. In larger fish these dorsal and anal fins grow to a large “sickle” shape and often protrude above the water when the fish are feeding on the surface.
The WA state spearfishing record is 48.7kg held by Glynn Dromey. This fish was taken off Ledge Point way back in 1972, several fish close to this have been shot such as this fish by Scott Paxman.
Also this great fish by Barry Paxman
The state angling record is over 80kg so bigger fish certainly exist and it gives an indication of just how difficult these fish are to capture.
Southern bluefin can be separated from Longtails by a more solid body shape, they are dark blue from above and silvery below. The current WA spearfishing record is just 3.8kg taken by Barry Paxman at Rottnest. The state angling record is just over 10kg, while the national spearfishing record is 28kg held by Greg Pickering with a South Australian fish. Obviously they get much bigger (at least 80kg in WA waters). Basically few large ones are sighted, I have seen a group of 6 fish over 60kg each of Esperance and I know of a diver who was circled by a very large one of Walpole while he was unloaded. It probably just a matter of time before someone gets a large fish in WA, particularly with more divers venturing far offshore.
Southern Bluefin and Longtail tuna have quite different body shapes
Longtail have quite an elongated body and very small pectoral fins compared to the other species commonly seen in WA. They also have pale spots on their underbelly. Longtail don’t get as big as their cousins, with the national record at 21.7kg and the state record at 9.1kg.
Dogtooth are readily identified by their large doglike conical teeth, scaleless body and prominent white spot near the tail. Often this spot if the first thing noticed by divers as the fish blend in well to the deep clear waters that they inhabit. The WA spearfishing record was taken at Scott Reef by Greg Bush with a fish of 59.5kg. This record has stood since 1996 partly because dogtooth haunts are difficult and expensive to get to and partly because hunting dogtooth is really a battle of diver VS fish and diver VS sharks trying to eat speared tuna.
Tuna, like many pelagics, prefer deeper edges adjacent to headlands or reef, channels between reefs and current lines. Although they can be found over any type of bottom if there is bait fish to attract them. In WA sub 20kg fish are often in a group of 20 or more fish however the bigger they get smaller the group size seems to be.
Tuna generally appear rapidly on the edge of visibility and do a circle or arch around the diver before disappearing. Sometimes they will make a second pass, however they rarely approach any closer and are generally moving fairly fast, making a very difficult target.
The exception is when something catches their interest under or behind a diver, generally burley or a flasher. They will sometimes try to “take a shortcut” to investigate the object of interest, normally the last “short cut” they take!
It is difficult to judge the speed of a tuna as they tend to “swim without moving” but as a rule they are always further away and going faster than what you think. Therefore aim well forward. Even doing this many shots will fall short or hit the fish in the last 1/3. On the upside a thin 7mm spear from a railgun will hold well in the sinew filled tail of the tuna, just be ready for a long fight!
Northern Bluefin are probably the easiest species in to spear WA, mainly because they can be found in feeding schools on the surface. In this situation a diver can enter the water upcurrent from the feeding frenzy and drift into the school. The fish will still be moving fast but a generally very close
This is probably the only species in WA that can truly justify a multi-rubber “canon”, mainly because they are generally speared from a fair distance and are a thick bodied fish with a solid spine.
Having said that, as they are not common enough to target specifically, most fish in WA are taken with 1.3 to 1.5m single rubber guns by divers targeting mackerel. Reel guns can be used, however, as these fish tend to head straight down when hit, the diver must have roughly 1/3 more line than the depth of the water.
Bungie setups are a definite advantage as these fish never give up and even a 20kg fish has more stamina than a diver.