Dogfish

Lesser-spotted dogfish

    • Scientific name: Scyliorhinus canicula
    • Also know as: Lesser-Spotted Dogfish, Small-Spotted Dogfish, Small-spotted Catshark, Rockfish.
    • Size: Up to 3ft and 5lbs (UK shore caught typically 1-2lb).
    • UK minimum size: 15in/38cm in length
    • UK shore caught record: 4lb 15oz
    • IUCN Status: LC (Least Concern)
    • Distribution: Found all around the UK but in generally in greater numbers on the south and west coasts of the British Isles. It is also found throughout the Mediterranean,  coasts of northern Africa, and in Scandinavian waters.
    • Feeds on: Extremely unfussy scavenger that will eat pretty much anything it can find. Worms, fish, prawns, shellfish and crustaceans will all be taken, as will small fish it can hunt down.
    • Description: Long, slim body which is tan or light brown and covered in small dark spots and skin is very rough to the touch. Underside is light grey to white in colour. Mouth is set quite far back on underside of body and nasal grooves reach the mouth. Two dorsal fins are set far back on the body and pectoral fins are large and triangular. As this is a shark species there are no rays, spines or segments in the fins, and five gill slits are present on each side of the body.

Dogfish are common around the UK, especially around the south and west, and their willingness to feed on pretty much any bait, presented on any rig sees them turn up regularly in anglers’ catches. This abundance, coupled with the small size of dogfish, means that anglers can at times see dogfish as a pest species when they repeatedly take baits mean for bigger and more desirable species. However, the dogfish is a member of the shark family, and does provide a dependable catch on days when little else is biting, especially as dogfish feed just as well in bright sunlight as they do at night. The dogfish lives and feeds on the seabed in relatively shallow water around the UK, rarely venturing beyond fifty metres deep, and prefers sandy to mixed ground, although they can be found in numbers in some rockier marks.

How to hold a dogfish

The best way to hold a caught dogfish.

The dogfish is not particularly nice to eat and has little commercial value, although it was once highly sought after for its rough skin which was used to polish wood and as a replacement for pumice. The fact that, unlike other fish species, dogfish have to be skinned before they can be filleted puts commercial fishermen off catching this species due to the extra work and processing time this takes. Occasionally dogfish will be sold in fish and chip shops or fishmongers under the name of Sweet William (probably to hide the fact they are selling the unappealing dogfish). The population of dogfish appears to be staying stable and even increasing in certain seas around the country – a rare thing indeed in these days of huge commercial pressure on fish stocks. Caught dogfish can prove difficult to unhook as they twist their body and tail around the angler’s arm, and their rough skin can cause painful abrasions. The best way to unhook a dogfish is to firmly hold its tail alongside its head (as the picture above shows) which prevents it from trashing around and allows it to be unhooked easily. Some anglers have an irrational dislike for dogfish and use the relative abundance and pest reputation of this species as an excuse to treat caught dogfish badly, for example yanking hooks out of the mouths of dogfish and launching or kicking the fish back into the sea. No fish should be treated like this and the reputation of all anglers suffers when members of the public see this.

Other Species of Dogfish

There are other species found in UK waters which have the name dogfish associated with them, but they are relatively rare compared to the abundant lesser-spotted dogfish. The bull huss – also known as the greater-spotted dogfish – is probably the best known to anglers (there is more information on this species below). However, there are other dogfish species referred to by the dogfish name which anglers rarely encounter. The blackmouth dogfish (Galeus melastomus) is a small fish which does not grow much bigger than two feet in length. It is light brown in colour with a distinctive marbled pattern across its back and flanks and its mouth and tongue is unsurprisingly black in colour. This fish has a widespread by dispersed population, being found all of the way from Iceland to Africa. However, blackmouth dogfish rarely turn up in anglers catches as it is a deepwater fish, living and feeding in depths of at least 100 metres, and can be found all of the way down to 1000 metres and deeper.

Blackmouth Dogfish

Blackmouth dogfish have a distinctive mottled pattern, and right, the black mouth and tongue of this species.

Like the lesser-spotted dogfish the blackmouth is a scavenger eating crustaceans and molluscs, although it will also feed by hunting other fish. Evidence exists that blackmouth dogfish may hunt in packs to take down fish which are too big for them to tackle alone, such as skates and rays. Blackmouth dogfish have no commercial value in the UK and only limited value in the rest of Europe. They turn up often in commercial catches as bycatch. Little is known about the numbers of this species.

Confusion with Bull Huss

Large lesser-spotted dogfish can be confused with the bull huss, which is also known as the greater-spotted dogfish. There are several key differences. Firstly, the bull huss reaches a greater size – up to 20lbs – meaning anything larger than 5lb is almost certainly a bull huss (indeed, a 5lb or heavier lesser-spotted dogfish would be a new British shore caught record). Secondly, the bull huss has fewer but larger spots on the body, while the dogfish has more, smaller spots on their body. However, the final and most accurate way of telling the difference between these species is to look at the mouth and nasal area. In the lesser-spotted dogfish the grooves from the nasal openings continue along until they reach the mouth, whereas in the bull huss they do not.

Reproduction

Mermaids's purse

Mermaids’s purse

Most fish reproduce by releasing hundreds of thousands – or even millions – of eggs into the sea. The vast majority of these will be eaten by predators, washed onto the shore or prevented from hatching in some other way. However, the sheer weight of numbers means that at least a few will make it through to maturity. However, dogfish have a different method. They lay fewer eggs in protective cases, known as mermaid’s purses. These cases attach themselves to rocks or vegetation and protect the fish as it develops inside. The dogfish grows inside these cases for around ten months. Once it is ready to hatch the baby dogfish is between four and five inches long and can fend for itself. This gives dogfish a higher survival rate than many other species as the young dogfish are already fairly developed and able to avoid predators. In areas where dogfish are common empty mermaid’s purses can be found washed up on the shore.

Techniques and Methods to Catch Dogfish

Two Hook Flapping Rig

The two hook flapping rig is ideal for catching dogfish – buy one from Sea Angling Shop by clicking here.

Fishing for dogfish is not complicated. Simple one or two hook flapping rigs with size 1/0 or 2/0 hooks presented on the seabed is all that is needed. Fish baits such as mackerel strip, squid and sandeel are commonly used to catch dogfish, although they are a famously unfussy species which will take almost any bait an angler offers. Baits should not be too large as the dogfish has a small crescent-shaped mouth, situated fairly far back on the underside of the body which forces the fish to turn sideways to attack its prey. Despite the pest species tag some anglers attach to dogfish, in these days of dwindling fish stocks many anglers are happy to count dogfish in their catch at the end of a day’s fishing. In areas where dogfish are numerous and anglers are fishing with rigs with multiple hooks a dogfish can be taken on every hook if a shoal descends on the area. The status of the lesser spotted dogfish as a small shark is underlined by its modest UK shore caught record of 4lb 15oz, which has stood since 1988, while the UK boat caught record is actually a smaller dogfish of 4lb 9oz caught in the Irish sea in 2005.

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