Skipjack Tuna
Category: Medium Risk
SKIPJACK tuna, or stripies as they are frequently called these days, are mainly encountered by boat anglers, although at times they can come inshore to feed if conditions are right. They can be seen characteristically feeding and jumping as they speed across the surface, often accompanied by flocks of hungry sea birds. They feed and travel everywhere fast and their short lives must simply be a blur. On a line they display a level of energy and power that often belies their diminutive size, so on light spin gear they can be a real buzz.
Stripies are very prolific and are caught commercially in huge quantities, with over two million tonnes annually being taken around the world. Like all tunas they have no swim bladder so they must constantly keep swimming, a task to which they are well adapted.
Unfortunately for stripies they are high on the preferred food list of many large game species and therefore are seen as a good bait option by many anglers – be it for cut, dead or live baits. The ocean would indeed be a quiet place at times without schools of stripies busting up all over the surface.
Identification
The stripes that run along the body are the most obvious identification feature for stripies. Their backs are a dark purplish-blue, and lower sides and belly silvery, with up to six very conspicuous longitudinal dark bands on the lower sides of the fish.
Size
The biggest stripie recorded in Australian waters was a 12.2kg monster taken in Queensland, but closer to home a 10.6kg fish was caught off Perth as recently as 2000.
The vast majority of stripies caught by anglers are in the 2-3 kilo range, with a good one being over six kilos.
Distribution
Stripies are found right around the world in tropical and warm-temperate waters and are distributed throughout West Australian waters.
Breeding and migration
Skipjack tuna spawn in batches throughout the year in equatorial waters off our North-West. From spring to autumn they spawn farther south in subtropical waters, with the spawning season becoming shorter as distance from the equator increases. They mature at around 45cm at which time they are capable of laying up to two million pelagic eggs a year. These eggs hatch after just 1-1.5 days and the larvae move south to cooler waters with the ocean currents.
Stripies feed on just about everything and are cannibalistic. In turn they are prey to larger tunas, billfish and sharks.
Little detailed information is available about migration patterns of stripies, but it is likely that the primary driver in WA waters is the Leeuwin Current that flows southwards from the tropics. Stripies move south with the current feeding at the boundaries between cold and warm water masses and upwellings, where baitfish are most abundant.
During their 8-12 year lifespan they feed and travel mostly on the surface but they can range down to about 260m during the day, although they tend to stay around the surface at night.
Threats
There are currently very few threats to stripies in Australia and in WA we thankfully don’t have a tuna fleet dedicated to chasing them.
Tackle and bait
Chasing stripies is best done with lures as they love dining on a fast moving menu. For casting a light spin stick and threadline reel loaded with 2-6kg mono, or braid, are just ideal, with a metre of 10kg mono trace at the business end of your rig. And for trolling I would probably use a small baitcaster rather than a spinning outfit.
The list of casting lures that will catch stripies is endless - poppers, bibbed and bibless minnows, metal slices, lead-head jigs, flies and even soft plastics. When it comes to trolling lures, feathers and small skirted lures are very effective.
Fishing methods
When sighted within casting range of the rocks the most important thing is to be quick and get your casts in before the school races away. High-speed metal lures and lead-heads are most effective in these circumstances.
Offshore you will often find stripies hard to get close to, as they have a disturbing tendency to sound when a boat approaches. At times, if you simply cut the motor a couple of hundred metres from the fish they will continue feeding and travel past your boat within casting distance.
However, probably the easiest way to catch stripies is to troll past them with small skirted trolling lures well out the back of the boat. By turning the boat back in the direction of the school once comfortably past the fish, you will drag your lure towards the feeding stripies and hopefully be rewarded with a hook-up.
Whenever you hook a stripie be prepared for a tough fight from these little speedsters as they always give a very good account of themselves.
References: Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston.
Australian Fisheries Resources by Kailola, Williams, Stewart, Reichelt, McNee and Grieve.
Fisheries Global Information System of Food & Agriculture Organisation of the United Nations.
SKIPJACK tuna, or stripies as they are frequently called these days, are mainly encountered by boat anglers, although at times they can come inshore to feed if conditions are right. They can be seen characteristically feeding and jumping as they speed across the surface, often accompanied by flocks of hungry sea birds. They feed and travel everywhere fast and their short lives must simply be a blur. On a line they display a level of energy and power that often belies their diminutive size, so on light spin gear they can be a real buzz.
Stripies are very prolific and are caught commercially in huge quantities, with over two million tonnes annually being taken around the world. Like all tunas they have no swim bladder so they must constantly keep swimming, a task to which they are well adapted.
Unfortunately for stripies they are high on the preferred food list of many large game species and therefore are seen as a good bait option by many anglers – be it for cut, dead or live baits. The ocean would indeed be a quiet place at times without schools of stripies busting up all over the surface.
Identification
The stripes that run along the body are the most obvious identification feature for stripies. Their backs are a dark purplish-blue, and lower sides and belly silvery, with up to six very conspicuous longitudinal dark bands on the lower sides of the fish.
Size
The biggest stripie recorded in Australian waters was a 12.2kg monster taken in Queensland, but closer to home a 10.6kg fish was caught off Perth as recently as 2000.
The vast majority of stripies caught by anglers are in the 2-3 kilo range, with a good one being over six kilos.
Distribution
Stripies are found right around the world in tropical and warm-temperate waters and are distributed throughout West Australian waters.
Breeding and migration
Skipjack tuna spawn in batches throughout the year in equatorial waters off our North-West. From spring to autumn they spawn farther south in subtropical waters, with the spawning season becoming shorter as distance from the equator increases. They mature at around 45cm at which time they are capable of laying up to two million pelagic eggs a year. These eggs hatch after just 1-1.5 days and the larvae move south to cooler waters with the ocean currents.
Stripies feed on just about everything and are cannibalistic. In turn they are prey to larger tunas, billfish and sharks.
Little detailed information is available about migration patterns of stripies, but it is likely that the primary driver in WA waters is the Leeuwin Current that flows southwards from the tropics. Stripies move south with the current feeding at the boundaries between cold and warm water masses and upwellings, where baitfish are most abundant.
During their 8-12 year lifespan they feed and travel mostly on the surface but they can range down to about 260m during the day, although they tend to stay around the surface at night.
Threats
There are currently very few threats to stripies in Australia and in WA we thankfully don’t have a tuna fleet dedicated to chasing them.
Tackle and bait
Chasing stripies is best done with lures as they love dining on a fast moving menu. For casting a light spin stick and threadline reel loaded with 2-6kg mono, or braid, are just ideal, with a metre of 10kg mono trace at the business end of your rig. And for trolling I would probably use a small baitcaster rather than a spinning outfit.
The list of casting lures that will catch stripies is endless - poppers, bibbed and bibless minnows, metal slices, lead-head jigs, flies and even soft plastics. When it comes to trolling lures, feathers and small skirted lures are very effective.
Fishing methods
When sighted within casting range of the rocks the most important thing is to be quick and get your casts in before the school races away. High-speed metal lures and lead-heads are most effective in these circumstances.
Offshore you will often find stripies hard to get close to, as they have a disturbing tendency to sound when a boat approaches. At times, if you simply cut the motor a couple of hundred metres from the fish they will continue feeding and travel past your boat within casting distance.
However, probably the easiest way to catch stripies is to troll past them with small skirted trolling lures well out the back of the boat. By turning the boat back in the direction of the school once comfortably past the fish, you will drag your lure towards the feeding stripies and hopefully be rewarded with a hook-up.
Whenever you hook a stripie be prepared for a tough fight from these little speedsters as they always give a very good account of themselves.
References: Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston.
Australian Fisheries Resources by Kailola, Williams, Stewart, Reichelt, McNee and Grieve.
Fisheries Global Information System of Food & Agriculture Organisation of the United Nations.
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