Following on from my introductory feature in last months issue, I’m now going to drill down in to each species over 100lb I have targeted from my small boat. This month I take a look at one of the more abundant species available to us, the blue shark.

Blue sharks are pretty obliging fish and 100lb fish are not that un-common, this coupled with the fact that many of the principles involved translated to species further down my list meant they made a logical place to start looking in my hunt for ton up fish.   

Off the south west coast of England all the way round to Ireland they can be found in good numbers throughout the summer months and they are not that hard to target. The summer months, during which they are present, means there are often good weather windows available for me in a small boat, so these were the first big fish I chose to target.

At the time, my work meant that I couldn’t fish from mid July until February so the blues were an easy place for me to start, they are also a good way to test your systems for some of the other species as you get plenty of chances to practice your routine handling fish of a decent size, test your crimping and rig building, make sure your chum mix isn’t a complete disaster etc. You’d rather lose a blue knowing another will soon be along, than lose the sort of species you might be lucky to get one run from in weeks of targeting!

Blue shark biology-

You don’t need to know everything about shark biology in order to target blues, there’s plenty available on a Google search so I’ll stick to the relevant bits here that will help you be more effective in fishing for them.  The way blue sharks work is that the populations of males and females spend much of the year apart, coming together to mate.  After this they largely split. The males (unusually in nature these are bigger than the females) head towards the states, whilst the smaller females come our way to drop their live pups (normally 25-100), arriving around June when our water temperature hits around 14 degrees.

This split of sexes allows the pups to be born without the cannibalistic males eating them!  The bigger fish seem to be more easily targeted early and late in the season when the water is cooler.  As the water warms in mid summer, smaller fish become more prevalent and you can catch higher numbers in a day than early and late in the season but generally with a smaller average size.  The bigger fish seem to follow the cooler water. Whilst there are still odd big fish around in mid summer, the smaller fish are more numerous and they tend to beat them to the baits. My research told me that early and late in the season were the best times to go for a fish over 100lbs. 

Blues are a pelagic fish that like deep water below them with the generally accepted depth required to find them reliably being somewhere around 240ft, although I have caught them in much shallower water than that.  Females tend to top out at around 250-300lbs.  Since our population is nearly all females, we’ll assume that without a rogue male turning up unexpectedly (they sometimes do) that will be about as big as we expect to get around the UK. The vast majority being much smaller-around 30-60lbs, so a 100lb fish is still above average and a fair challenge. Blues have an incredible sense of smell and will track a scent for miles, this translates from a fishing point of view into never breaking your slick if at all possible, more about that later.

Tackle and rigs-

Blues can fight well on the right gear but they’re just not the same as some of the bulkier fish, most rods and reels in the 20-30lb class will cope with the majority of blue sharks, so if you’d only like to see if it’s for you, most people already have tackle adequate to cope.  I normally go in over gunned as I’m always considering the possibility that something a bit special might take a bait and I’d hate to lose the fish of a lifetime when it comes along.  I like rods with a bit of give in the tip and typically use 30-80 Penn Allys as they give enough for you to enjoy the fight but also will cope with most other things swimming around down there should you be lucky enough to hook up.

Reels can also be smaller than with most of the other big fish targets as blues don’t run particularly far or fast. Models like Shimano TLD 20’s are more than adequate, again, I like to go bigger in case of a bigger fish and have settled on Avet ProEX30s for most of my general fishing but whatever you’ve matched to your 20-30lb class rod should cope if you’re wanting a to give blue sharks a try.

Blues have sharp teeth and rough skin so you need to protect against both, I find a 17ft trace is enough to do this.  5ft of 49 strand stainless cable for the teeth and 12ft of heavy mono for the skin; this sounds long compared to the fish but blues in particular will roll up a trace so you need enough to keep them away from your mainline. 17ft is a manageable length to handle on your own.

The more fishing I do the more I tend towards 480lb AFW for the biting trace, I’ve used lighter wire in the past but had it fray (and not break) during the fight even with blues, so now I stick to the heavier gauge for everything.  Again, with the mono rubbing leader I use 400lb Momoi as blues don’t seem to mind the heavier approach.

Starting from the rod tip I have a crosslock swivel which connects to a Flemish eye in the 400lb mono at the top of the rig, with an alloy crimp matched to the diameter of the mono.  You can use copper double crimps but the alloy ones are less prone to damaging the mono in my opinion. I generally put a Flemish loop in the mono to add abrasion resistance to where it touches the metal on a connection, at the other end of the 12ft I put another crimped Flemish loop.  On the wire I use another crosslock that is attached to the biting trace using another Flemish eye and a copper double sleeve matched to the diameter of my wire. The addition of a crosslock here means that I can remove 12ft of trace quickly in order to untangle a fish since blue sharks are prone to rolling up the trace both in the water or in the boat.

At the other end of the biting trace is the hook, I’m not too particular on hooks for blues and anything strong around a 10/0 will work, it must be strong and sharp and personally I grind the barb down, this helps hook penetration and also unhooking.  I have tried circle hooks on Blues and whilst they have worked, I’ve had a better hookup rate using J hooks, deep hooking is easily avoided by striking in good time with a few hard jerks on the rod once the line has come tight.


Since we know blues like deep water, this has to be the first consideration. The Cornwall area I fish has a long history of blue shark catches so I personally chose to start my search there in June to have a crack at a big fish. 

When fishing from a drifting boat, the longer the drift the longer the scent lane so if the weather allows me to be picky, I’d choose spring tides over neaps to enable me to cover more ground. To further increase my chances I like to start by establishing the direction I will be drifting in by stopping the boat on the way out, I then take this into account when planning my starting point for the day, making sure that this line on my plotter won’t take me into a land mass or anything else that will force me to break my slick before the end of the day. 

Once I’m happy I have enough open water in front of me I’ll put a chum bucket over the side and motor in the direction of my intended drift for a mile or two at a slower speed, around 5 knots. This is also a good opportunity to motor directly over wrecks in the nearby area as they can hold all sorts of bonus fish that may follow the slick to the boat.  This “power chumming” gives you a couple of miles extra slick when you start the day and it increases the odds of catching a fish from the off in my opinion. It’s also good as fish are curious things and will sometimes follow the noise of the boat and you can get really quick hookups. I think as well as curiosity many fish are conditioned to associate the noise of an engine at sea with discarded fish from commercial boats and a free meal.

Whilst power chumming, I’ll get a bait in the water close to the boat as a slow troller then when I get to where I want to start fishing I kill the engine and begin setting other baits up.  The bait in the water from the off can be a real bonus and pick up the early fish that’s come to the noise of the boat whilst the other baits are being prepared. Blues are not fussy eaters and I’ve caught them on a variety of baits. Fresh is always going to be better but frozen is also fine, I generally start with frozen baits for speed and change them out for fresh mackerel and whiting as soon as I have them, both of which can be feathered up whilst fishing during the day.

Chum is a vitally important part of your setup for blues, so a quick word on it here.  It should really be prepared in advance of the day to make the most of the available fishing time. I keep a chest freezer full of frozen blocks ready to go at a moment’s notice! My mix is really simple and is the tried and tested Pullen recipe of trout guts and bran. I have a table farm near me so just blend up the guts and gills with a plasterers whisk, add the bran then freeze it in blocks.  

The key to good chum is plenty of oil, so make sure you don’t mix it too dry, you’ll see a good slick develop on the surface once you start chumming if you’ve got it right. The trout are fed so much oil as part of their diet I don’t personally add any extra although plenty of people do add fish oils to their mixes, for blues I see it as an unnecessary extra expense.

The theory of chumming from a boat is that the chum sinks and widens as it gets progressively further from the boat like a torch beam, the fish follow this beam to the boat and so it would make sense to keep your baits within that beam.  This means the baits need to be progressively deeper the further you go from the boat, to set the depth you will need to use a float of which there are many different types, whatever you choose to use make sure that when a fish takes it is able to trip and slide up and down the line-there is enough rubbish in the ocean without us adding to it with tripped balloons and plastic bottles all over the place. 

A common mistake it that anglers will set a bait deep and assume the depth they have measured off is where the bait is fishing; not so! The deeper the water, the more of an effect drag has on the bait so it will kite up in the water and be fishing shallower than you think.  This can be countered by adding a sliding weight to your trace above the biting trace, shallow baits don’t require any lead in some areas due to the reduction in drag.   Stronger tides also mean more drag and therefore more lead on the trace.

It makes sense to send the deepest bait out first to reduce tangles caused by trotting lines past each other. I fish 3 rods when I’m on my own, 4 if there is someone else with me.  Once I’ve sent out the 2 deeper rods I’ll pull in the one close to the boat, re-set it around 20ft deep and send it back a few metres.  Once I’m drifting I keep my eyes open all the time as it’s not unusual for a shark to take a look at a float and you’ll see the dorsal out of the water, they will also come right to the bucket on the back of the boat, if this happens I’ll reel in the closest bait and gently free-line it back to the fish. 

Takes from blues are normally pretty assertive and they are not too finicky, the float will often disappear and the ratchet on the reel will sing out to let you know there’s a fish on, so strike in good time and settle down to the fight. The same principle applies as with all fish, allow it to take line when it’s pulling drag and gain line when you get the chance.  As I’ve said, blues can fight well but they’re not a fish that’s terribly difficult to deal with so they’re a good place to start your big fish hunt, the main thing to watch out for is your line touching any part of the boat, in deep water like this you shouldn’t really have much to worry about much else.

Handling, measuring and releasing-

Once you’ve fought your shark up to the boat things get more interesting. With any of these bigger fish you really should be sure that the fish is tired enough before leadering it. Green fish are very dangerous and taking a wrap on a big fish can be one of the last things you do if you get it wrong- they can and will pull you over the side! Always have a means of cutting wire or line tied to you during a fight, so should the worst happen you can cut yourself free. I say tied in case you drop it in panic in the water, this way you can have another go. I also use wiring gloves to reduce the pressure on my hands, another good tip is to add heat shrink tubing to any crimps on the wire as it contains the splinters produced when the wire is cut and stops them going into your hands during the wiring process.

Accepted best practice now is to leave sharks in the water for measuring and releasing.  If a fish is wrapped in a trace or you particularly want a photo then I personally have no problem with the odd fish coming aboard. This makes dealing with and measuring the fish easier and more accurate.  Some fish are just too big to get in the boat or handle safely.  Also, the bigger a fish is, the more prone to internal damage it is by being removed from the water, as the water provides a lot of support to the internal organs and removal can cause welfare issues if badly managed.  So, you now have your memory of the fight and photo,  plus maybe the length and girth measurements of your fish to calculate an approximate weight, make sure you write them down straight away as it’s easy to forget them in the excitement!

The days of hanging up fish for a weight are thankfully long gone and most reasonable people have no problem with a fish being held on the leader and measured as counting as caught; the formulas have been in use for quite a while now, to the point that a lot of people have never hung up a big fish so they’re a great way of comparing the size of your own personal catches relative to others. 

It’s now time to unhook the shark and release it, on smaller sharks I use a standard stainless “T-bar” disgorger, a quick pull and the hook is out and the shark can be released, on really large fish I have had a disgorger made up that’s around 3ft long so I don’t have to get anywhere near the sharp end! Sharks obviously have very sharp teeth so don’t get near enough for them to cause you any damage.  A bite, even if the shark didn’t intend it, is going to be very serious at sea and most likely going to mean the end of your fishing and a hospital trip.  If the fish has taken the hook beyond where you can remove it in good time without causing the fish damage then cut the leader as close to the mouth as possible. 

Tagging is a subject that divides opinions, if you choose to take part in a programme then fish should be tagged just before release.  If the fish is in the boat it can then be gently lifted over the side and recovered, facing into the tide to push water over the gills, if it’s been kept in the water then recover it on the trace and unhook it once the fish shows signs of swimming away under its’ own steam.  I’ve never had to start the engine during a fight with a blue but with some of the harder fighting species you would have the engine running by now, it’s then a case of holding the fish by the trace and putting the boat gently in gear to force water over the gills and promote a quicker recovery.  There is some good best practice handling advice available online here on the Shark trust website so I won’t repeat it now. 

If at all possible during the fight make sure your chum bucket keeps giving out a slick, this is a fundamental part of increasing your chances of catching more blues, breaking your slick accidentally or moving areas means that any sharks following you arrive at the end of the chum lane and find no baits.  They will turn away-even if you are close by.  Scent is tremendously important to them so keep that chum going in, keep the baits in the slick and tight lines.

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