They're cartilaginous fish, skates and rays. That is, they don't have a bony skeleton like true fish, but have one made of cartilage. Along with their close cousins - the sharks - skates and rays don't have a swim bladder, which makes skulking around on the seabed that much easier.
For instance, none of these types of fish have scales. Instead, they're covered with backward facing dermal denticles which gives them a coarse sandpaper-like skin.
Along with sharks, these fish have external gill openings, without the gill covers of bony fishes. And they all sport relatively long snouts, with a transverse mouth some way back on the underside of the fish.
OK, getting back to the key differences between skates and rays...
A 'Mermaid's Purse'
In these, the eggs of the female skate develop until the the young are mature enough to break out and stand a sporting chance of survival in nature's cruel world. Some types of sharks, lesser-spotted dogfish for one, similarly produce these egg cases.But rays don't. Unlike the skate - which are oviparous (egglayers) - rays are viviparous, giving birth to live offspring which have developed within the body of the female.
They're distinctly unadventurous fish, skates and rays, preferring to spend their days lurking camouflaged on the seabed. Once they find a habitat they like, they tend to stick around - long-distance swimming and seasonal migration just isn't their thing at all.
This is the largest of all Atlantic skates, reaching a length of up to 2.5m maximum and weighing well over 100kg, although a fish of this size is extremely rare.
The current British rod caught record Common Skate weighs in at 227lb and was caught off the Isle of Mull in the Inner Hebrides.
Adults live in depths of 100m to 500m, but juveniles favour shallower water.
The main food of the Common Skate includes marine worms, sandeels, crabs and flatfish.
Also known a Roker, the Thornback Ray is something of an impostor, as it is really a skate.
They reach a maximum length of 1.2m and favour muddy seabeds in depths of 20m to 100m, where they feed on small flatfish, crabs, prawns and sandeels.
The British record for rod caught Thornback Ray currently stands at 31lb 7oz and was caught in Liverpool Bay.
A ray that is well worth being able to identify quickly is the Stingray, as that poisonous spine can cause you a very painful wound. The spine can be up to 350mm long, and is shed several times during the fish's lifetime.
Stingrays favour relatively shallow water, where they feed on small bottom living fish, crustaceans and molluscs.
They seldom exceed 1.5m in length although specimens up to 2.5m long have been caught in nets.
They seem to be more tolerant of brackish water than other skates and rays, the British record of 72lb 2oz being caught in the River Blackwater estuary in Essex.
All artwork courtesy of Gyldendal Norsk Forlag
Downrigger ~ The cranelike device incorporating a line-counter reel often seen on the sterns of sport-fishing boats, which lowers a trolling weight on a wire line to a pre-determined depth. The trolling line is attached just above the weight, which gets the lure down to depths that would otherwise be unachievable.