Cobia are a widespread species across the northern Australian coast year-round – they fight hard, eat lures or baits and are often caught by anglers. Cobia – also known as black kingfish – grow in excess of 40kg but are more commonly caught around 10 to 15kg in size. At this size the fish put up a great fight and are fine for the table. The larger cobia over 20kg are exceptional fighters and seem to never give up, but these large trophy fish are not as good to eat and should be released. There is a massive range of techniques and tactics you can use to target and catch cobia. In this article, we will explore these and a few of the cobia’s habits.
Cobia move a little further south each year with the warmer waters, but are most commonly found in waters north of Sydney on the east coast. They continue all the way across the north of Australia, right around to Shark Bay in WA. Cobia are most commonly caught inside the shelf in coastal waters from 5m to 100m deep, but will occasionally move into offshore waters over the shelf. Cobia love structure, and reef edges, wrecks, wharves, marker poles and offshore rigs are some of their favourite spots to hang about. Cobia also love hanging about large manta rays and sharks so anywhere you find these, there’s a good chance cobia will be too. Cobia mostly hang in small schools of 2 to 20 fish and cruise around like their cousins the yellowtail kingfish. The larger cobia are often solo fish but are sometimes seen in pairs or small groups. Cobia are always on the move and seem to never stay in one spot for too long as they hunt around. They are a midwater fish and swim around a long way off the bottom and have no problem coming up to the surface to feed or to have a look. They feed on a massive range of fish, squid and crustaceans, are very opportunistic and have a large mouth so will take on anything that swims and will fit inside their mouths.
So, any high structure areas in northern waters are good areas to start looking for cobia. Cobia also love high current areas such as channels and pressure points so if you can combine these features it will be a hot spot. I find cobia extremely active at night so fishing at this time is a great option; first and last light are also absolute prime times. Cobia will feed at any stage of the tide, whether running or slack. Running water tends to hold them close to structure, while on the slack water they can be found swimming in open water more. They also show up well on a sounder as a few solid lines or marks midwater or towards the surface.
My favourite way to target cobia is via jigging and the cobia really do love a jig. You can really position the boat directly on top of the reef edge, wreck or marker pole and work your jig directly in the zone. Cobia will eat all styles of jig from wide-body, slow-pitch jigs to fast knife jigs, but my favourites are halfway between [IG1] both, with good flutter on the drop but still a more high-speed jig. Cobia will eat a jig on a variety of retrieves but the most effective I have found is just a medium-paced jig with a few small pauses every 15m or so of jigging. Use strong assist hooks on your jigs as cobia will bend out any of the lighter slow-pitch assist hooks. Pick a jig weight that matches the depth of water you’re fishing – I find my best cobia fishing is usually in water 30m to 50m deep, and in this depth I go for an 80 or 100 gram jig, depending on tidal and current flow. Jig colour doesn’t seem to matter at all but something with luminous paint or stripes is always good. Squid pattern jigs also seem to be deadly on these fish. I drop my jig all the way to the bottom and work it all the way to the surface for the cobia and as they are such midwater swimming fish it’s hard to tell where the bites are going to come from.
Live baiting is by far the most effective way to catch cobia. If you know the fish are down there and not hitting lures or other baits, live bait is the go. Cobia really get excited by a live bait and I’ve had fish at the back of the boat multiple times that won’t touch anything, but you drop a livie in and it’s instantly eaten. The best live baits are herring, scad or fusilier but with cobia, species of live bait doesn’t seem to matter too much and you can put down any small legal fish you catch. Just fish the live bait unweighted with a live bait hook in the nose and let in swim down to the fish. If fishing deeper water, you can put a ball sinker in front of your livie to help it get down.
Trolling for cobia is another technique you can use. I think trolling is slightly less effective than other techniques but it’s very effective in the right scenario. If you need to cover water and look for fish, trolling is a great option. The best lures to troll for cobia are deep-diving Bluewater Minnows such as Samaki Pacemakers; troll a little slower for the cobia than you would for mackerel, and a speed of around 5 knots is ideal.
Casting for Cobia
Probably the least effective way to catch cobia is to cast for them, but this is still achievable. If you can sight the cobia swimming on the surface or following a ray or shark you can cast lures at them and be successful. I have found the most effective lures to be big soft plastics, but I have also caught fish on stickbaits. Cast out in front of the fish and bring the lure past at the same height as the fish with the odd little pause and sweep. This is probably the most exciting way to catch a cobia and sight casting a cobia off a ray is something you will never forget.
Cobia will eat a massive range of cut bait from any fish, squid or prawns – they really are the garbage guts of the sea. In the past I would only catch the very odd cobia off the bottom when fishing for reef fish with bait. Quite often this was on the drop as the bait made its way down and a cobia picked it up. But I have since worked out if you have a midwater bait or one 5 to 10m off the bottom, you will drastically increase your catches of cobia. This is a great option for 5 or 10 mins after the bottom fishing goes quiet, and you can try this for a quick period before you move spots to see if there are any cobia around. They do find a midwater bait extremely fast due to constantly swimming around.
Rigging for Cobia
I like to target cobia on 10 to 15kg rated rods with 50lb braid and 100lb leader. These slightly heavier lines will put you in with a chance of landing a trophy 30kg fish if you do happen to hook one, and 10kg fish still put up a great fun fight on this gear. 10000-sized spin reels match these rods and lines perfectly and something that holds around 200m to 300m of the 50lb braid is ideal. The first run on a big cobia can be exceptional and will dump a serious amount of line from the reel. Cobia don’t give up easily and even at the boat the fish can be a real handful. Try to fight the fish right out before you go for a gaff or net as these fish are renowned for rolling off gaffs and breaking nets. I prefer to net cobia over gaffing them, or even just grab them by the tail and lift into the boat and save the stress of them rolling around in a net. Heavy gauge hooks are also a must for cobia as their big runs will test out hook strength. Thankfully, cobia aren’t dirty fighters and are rarely taken by sharks so you can let the fish run and fight without having to worry about these factors that lose so many northern species of fish.
There’s a massive range of tactics and techniques that can put you in with a chance of catching cobia. They are rarely a fish I head out to target on their own but by knowing these techniques, they are a great option to have a go at between spots or tides when out on the water. I often find myself jigging for cobia on wrecks after the reef fish go quiet or checking a few marker poles on the way home late arvo. The results have been great and by specially targeting these fish with a midwater option, it’s surprising how many you will find.