During the summer months, spider crabs congregate in huge clusters off our coastline, reaching a peak in August. No one is totally sure what they are up to but it's likely to be something to do with mating and moulting. Importantly, however, they make for excellent eating and this is the time to catch them.
Even in these more enlightened foodie times, you'll find it can be difficult to get hold of a spider crab from fishmongers. As a country we catch about 10% of Europe’s spider crab haul but hardly eat any of it, which is pretty inexplicable given that we scoff a huge number of brown crabs. Unfortunately for us, the vast majority (more than 90%) of our spider crab catch gets exported to France. In the last few years, some of the more canny British fishmongers have caught on to the small but growing market here, so if you look hard enough you should be able to find some near you.
You can catch your own spider crab fairly easily and without a pot. At low tide, snorkelling off any sand or shingle beach will often be fruitful. You'll find them loitering around patches of rocks and seaweed but they're also out in the open more (and therefore easier to catch) than their brown cousins. Alternatively, if you don't fancy getting wet, any angler will tell you that spider crabs will latch on to most baits left on the sea bed for long enough. Casting any smelly bait, like mackerel, a few metres off the beach and leaving it for 15 minutes or so will often result in a crab holding on when you reel in (it feels like an enormous dead weight so many people assume they've caught a lump of seaweed. As long as there's still bait on the hook, the crab will usually hang on while you retrieve with a slow, steady pull).
There are two types of spider crab you should avoid eating - any who have recently moulted and females carrying eggs. Both are easy to spot - you'll see the eggs on the underside of egg-carrying or "berried" females and recently-moulted specimens will have pristine shells. Look for older specimens covered in barnacles and seaweed (which they apply as a camouflage). It's generally better to eat the males because they have bigger claws with more meat.
Once you've caught your crab, preferably kill it in the recommended humane manner which involves piercing it twice – once between the eyes and once in the centre of the underside, at the tip of the abdominal flap – to kill both its nerve centres. Alternatively, if you're a bit squeamish, many people simply freeze the crab for a couple of hours to put it into a coma before plunging into a large pot of boiling water which still ensures a very quick death. In most areas the minimum landing size for a spider crab is 13cm. Frankly, your catch should be much larger if you want any kind of meal from it.
Cooking spider crabs is easy too - simply boil for 20 minutes per kilo. Most good sized crabs will be around the 1kg mark. Let it cool completely then get to work. It's worth the effort required to pick all of the leg and body sections because spider crab meat is very, very tasty. It's sweeter than the brown crab and you can substitute it in any recipe.
Have a go at these fantastic recipes:
Spider Crab Linguine (the Guardian) (pictured)
Baked Spider Crab (BBC Good Food)
BBQ Spider Crab (Food Mag)