The blue shark is distinctive having a long, slim in profile body shape, with long, slightly curved pectoral fins, whereas the pectoral fins on other sharks are noticeably shorter, and in proportion, wider. Also the upper lobe of the tail is elongated. The teeth are pointed, triangular, and with serrated edges for cutting.
The colour of blue shark in the water is also obvious being a deep indigo blue on the back, but with a grey to white belly. Only the mako in warmer climes has an obvious blue colouring to the upper body.
They can grow to close on 1000lbs and attain over 15-feet in length. Fish of this size having been recorded caught on longlines set for swordfish over the Flemish Cap. However in UK waters fish over 200lbs are not common. Without doubt though, the existing record has been beaten several times over the past few years, but anglers nowadays choose to release the fish alive after tagging and judging the weight using a length and girth measurement. A fish estimated to weigh 250lbs by knowledgeable anglers and a skipper was caught and released off Plymouth in the summer of 2011.
Most blue shark found in UK waters are females, with males rare. The females give birth to live young, these having a yoke-sac connection to the placental uterus. Females with up to 63 young have been recorded, but the number of pups is in relation to the size of the mother. The young are born at between 15 and 18-inches long.
They are an open ocean shark usually living in the mid water to surface column. They feed mainly on mackerel, herring, pilchards, but also squid, though occasionally drop to the seabed to feed on smaller prey fish such as whiting.
WHERE AND WHEN TO FISH
Blue shark are widely distributed around the world being found in the Pacific and Atlantic oceans. They are common off the western and eastern seaboards of the United States, South America, all around the African continent, and around Australia and New Zealand. In the Atlantic’s northeast quadrant they range as far as southern Norway, but also off France, Portugal and in to the Mediterranean.
The hotspots in the UK are the western side of the English Channel, the Channel Islands, the southwest of England, southwest Wales and the west of Scotland. Rarely are they found inside the North Sea. In Ireland they are found all along the south coast of Wexford, Cork and Kerry, but also caught as far north as Donegal, and off the Northern Ireland coast.
The season in the south of England, in Wales and off Ireland, starts in June, with August and September the peak months, though some sharks linger well in to October in milder years. Off Donegal and Scotland it’s normally mid to late July before the sharks show in numbers.
Good sea conditions for blues are often quoted as needing to be calm. Blues will feed in flat calm seas, but can tend to be shy of the boat and often stay deep when the water is settled and very clear. With enough wind to roughen up the surface and create small white caps and diffuse light penetration, this is when the blues often feed ravenously and in better numbers, and especially so if the sky is grey and overcast.
Blues can be caught on all sizes of tides, but experienced anglers would prefer the tides building from middle size towards high spring tides. This extra movement in the water can again induce greater feeding activity. That said, when bait fish shoals are well concentrated, blues will feed on the smallest neap tides, so there’s always a good chance.
Although these sharks will take up station over wrecks looking to feed on mackerel and pollack, they are more open water, far roaming sharks. For this reason many skippers choose to throw a bag of minced bran, oil and mackerel over the side on a rope and trail this the last mile when approaching the fishing grounds. This scent lane, called rubby dubby, plus the noise of the engines which blue sharks often associate with potential food having worked close to trawlers, can get the anglers early fish.
Once on the mark, the technique is to drift with the wind and tide. The ideal conditions are wind against tide, as this slows the speed of the boats drift over the surface, but with bags of rubby dubby out the scent is carried away from the boat to create a long, heavily scented trail of bran, oil and chopped mackerel that will encourage the sharks to follow the smell in to the boat to feed.
This scent trail is like the beam of a torch, widening and going deeper as it travels away from the boat. This dictates the depths at which the baits are set below balloons and what distance they are positioned away from the boat.
On fast tide flow days a sensible pattern would be four balloons set at 60-feet and about 100-yards from the boat, a second at 60-yards and some 40-feet down, the third at 25-yards and 20-feet down, and one just dropped over the side and set at 15-feet.
On days when the tide and drift are slow, a scent trail will be much wider and deeper. Again deploy four balloons. This time the furthest balloon is 100-yards out, but some 100-feet deep. The second balloon goes out at 60-yards and should be set 70-feet deep, the third is out 40-yards at a depth of 40-feet, and the final balloon is at 20-yards and set 20-feet deep. None of these depths and distances need be accurate, but are a general guide.
You can see from the patterning of the baits that the intention is to target sharks as they come in to the scent trail, then work upwards through the water column following the smell to its source. They either swim in to, or notice the suspended baits from below, when working inwards towards the boat.
On days when there is some sea swell the balloons bobbing on the surface induce movement in to the baits. But on calm days with little swell and therefore little bait movement, every ten to 15 minutes, try retrieving the baits in a few yards and releasing them back to the same position. This movement again can sometimes trigger an inquisitive but disinterested fish in to attacking.
BLUE SHARK TACKLE
The days of huge 6/0 reels and 50lb class rods for blues are now history. Modern blue shark fishing is about using sporting tackle for maximum fun. Normal shark gear is now a fast taper 20lb class rod matched to a reel holding about 400-yards of 20lb mono. Standard reels such as Penn Fathom 20’s or 30’s, or Shimano TLD’s are ideal.
Lever drag reels, such as the small Penn International 12’s give a smooth release of line off the drag when fishing light lines, yet still have the power and build to target huge fish. These more expensive reels are chosen by experienced shark anglers who fish sharks on a regular basis.
HOW TO BUILD A BLUE SHARK WIRE TRACE
BAITS
The top bait for blue shark is a whole mackerel. Cut the tail off, now pass the point of the hook in through the cut tail and bring the point out naturally a little way down the body. Put the point of the hook back in to the same hole and bring it out again further down. Continue this “stitching” method until the hook comes out just rear of the gills. This sees the mackerel fish head downwards. You can also add a single mackerel fillet to the hook by one end, or a whole squid, to add movement.
When using mackerel flappers and putting the hook just in through both jaws, sharks can all too easily nip off the fillets and miss the head and hook. The whole fish, head down, is by far the most effective presentation.
TOP TIP 1
To attach the balloon, take 8-inches of supple phone wire and to one end twist on a size 6 rolling swivel. To the other end twist the wire around the tail of the balloon. Slide this on to the main reel line by the swivel, then tie the reel line to the top swivel on the wire trace. Above the balloon phone wire swivel, wrap in tight touching turns, a short length of telephone wire just tight enough to slide under finger pressure on to the main line. This is a sliding stop on the reel line that allows you to set the required depth for the bait. This sliding stop goes in and out of the rings easily and does no damage to the line or rings.
TOP TIP 2
Using heavy pliers, crimp the barb down on the hook so that it lays flat. This will not easily drop out of a hook hold in a sharks jaw if the line falls slack, but can be easily removed with long nosed pliers minimising any damage to the fish.
TOP TIP 3
When storing wire traces, coil them up in open wide coils secure them with phone wire or cable ties. This avoids any chance of the wire getting kinked which will dramatically weaken it.
TOP TIP 4
Every 15 minutes or so, bump the rubby dubby bags up and down on the rope in the water. This releases extra scent that can often induce an undecided shark to attack by stimulating its feeding instincts. Also make sure at least one bag of dubby is freshened with fresh mix every hour or so.
TOP TIP 5
Although the numbers of blues start to thin out in September, this is the time for the bigger fish to show. Many big fish have shown at the very end of September, and in early October, so for the big fish book your trips later in the year.
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