Though evil smelling and not for those with a delicate stomach, a rich concoction of old mackerel mashed up and mixed with fish offal, blood and bran, makes a killing groundbait for sharks.
Rubby dubby, a word coined in Cornwall in the 1950s when shark fishing began as a sport, was bor-rowed from American big game anglers. In America, ‘chumming’—throwing chopped up pieces of fish into the water—had long been used to attract tuna and other species of giant game fish.
The best dubby is made from oily pilchards, herring and mackerel, pounded to a pulp with a blunt in-strument. Fish offal and unwanted fish are constantly added and some skippers introduce bran to thicken it up. Blood collected from slaughterhouses is also a popular ingredient but contrary to belief it does not stay in a liquid state, due to it being a coagulant. It then resembles jelly, and is a useful additive to existing rubby dubby. Occasionally it is kept separate and after a good stir ladled directly into the sea with an old saucepan. Under the rules of the In-ternational Game Fish Association and the Shark Angling Club of Great Britain, the use of blood, flesh, and the guts of mammals for ‘chumming’ or ‘rubby dubby’ will disqualify a catch, so if you have a world or British Record shark in mind, make sure none of these are used on the boat.
Conventional dubby is placed in stout meshed bags or in small sacks and suspended over the side of the boat at bow and stern, a length of rope holding it just beneath the sur-face, where constant wave action keeps the oil and particles of fish flowing. Every so often the bags are bashed heartily against the side of the boat to help thing along. ‘Rubby dubby trail’
Once in the water the ‘rubby dubby trail’ gradually builds up. Pieces of flesh sink quickly or slowly, depen-ding on their oil content, while the oil droplets stay on the surface. On rough days it is quite remarkable how this trail smooths out the sea. If the trail is ‘fed’ regularly with fresh bags of dubby it becomes deeper and wider, forming almost a solid lane of attraction, leading a shark straight to the baited hooks.
Quite a few rubby dubby barrels are started at the beginning of the season. The mess is topped up each day; after a couple of weeks it is said to be of superior quality, guaranteed to attract sharks.
While the Cornish version is used mainly in British waters for sharking, many skippers operating bottom fishing trips attach a bag of fish guts and mashed flesh a few feet from the boat’s anchor rope. When the hook bites into the bottom, the tide flow carries particles of flesh back under the craft, thus attracting fish into the vicinity of the baited hooks. This variation really comes into the category of groundbaiting, and of course by comparison with a sharker’s dubby is not at all unplea-sant. Dubbying as used in shark fishing is a certain way of attracting mackerel. Drop a set of feathers into a slick that has been working for as little as ten minutes and the chances are that each hook will hold a shining mackerel.
It should be remembered that land predators always hunt upwind. Fish react the same way, and search for food uptide. It usually takes about an hour for the rubby dubby to do its silent but deadly work.
Shark boats leave harbour around 9.00am allowing two and a half hours to reach the ground, set up the drift and get the dubby in the water. It takes a further hour for a useful slick to build up, and half an hour for the shark to swim up it. Quite often a reel will ‘sing’ punctually at one o’clock.
Each boat has its own characteris-tics: those with large wheel-houses and high prows catch the wind rather more than craft with a lower profile. In certain wind-on-tide con-ditions some boats overrun the slick, and others side-slip, creating an undesirable bend in the trail. When this happens a fish can easily swim past the baits and continue hunting away from the boat.
Once the dubby is working, it is of course bad policy to break trail by moving to another area. When the drift is set, the pattern must be maintained until it is time to draw lines. This rule does not apply in Porbeagle shark fishing, which is confined to quite small areas of rocky ground lying well inshore. Crackington Haven in Cornwall and Hartland Point in Devon are only a matter of 400 yards from the land. In this situation, the boat’s drift pattern is short and repetitive; con-sequently a ‘box’ of attraction, rather than a lane is created. Unlike blue shark, which keeps to deep water, porbeagles will hunt in less than 30ft, so pure chumming with small pieces of fish is practised, in addition to having the conventional net bags at bow and stern. On several occasions, very large surface-swimming porbeagles have been coaxed to within a few feet of the boat with tasty morsels.
An alternative method when fishing at anchor over a small patch of rock is to drop a large weighted can filled with crushed fish mixed with pilchard oil. Holes should be punched in the side to allow the juices to flow out.
A word of warning to those who have never smelt rubby dubby—the effect is devastating to most newcomers to the sport of sharking and many old hands alike!
If you have a sensitive stomach, stand as far away from the bin as possible while the skipper is filling the bags. Many an angler’s day has been turned into a nightmare of seasickness.