Samui Wining & Dining
Catch of the Day

Finding out about everybody’s favourite crustacean – the crab.

P2-3-(1)You’ll have seen them displayed in many of the restaurants around Samui. And almost certainly have witnessed tiny ones scuttling around your feet on the beach. Although with those little creatures, I suspect you’d expend more energy trying to catch them, than any nutritional value you might gain!

Crabs are one of nature’s survivors, being found in all the earth’s oceans and, indeed, on land as well. Applied to several different groups of short decapod crustaceans, the term crab is a bit of a catch-all. True crabs are members of the infraorder Brachyura, of which there are around 4,500 species. Other types, such as hermit crabs, porcelain crabs and king crabs account for another 500 species but, despite superficial similarities, are not crabs at all. They are Anomura, and can be distinguished from true crabs by counting the legs. In Anomura, the last pair of pereiopods (walking legs) is hidden inside the carapace, so only four pairs are visible (counting the claws), whereas uninjured true crabs always have five visible pairs.

While crabs are related to lobsters and shrimps, they have evolved so that they can run or walk sideways, as well as burrow and swim. And the pincers, called chelae, located at the front, are used for fighting, display and feeding. They can see fairly well with their compound eyes and their sense of smell and taste are more advanced, helping them find food and mates more easily. It’s believed that their social behaviour is reasonably complex and they can be aggressive towards one another, with the males in particular often fighting to gain access to the females.

Virtually all species of crab live in saltwater, with only a relatively small number living in freshwater, and many are of substantial economic significance in fisheries, medicine and ecology. A great number of them are habitat-specific and thus excellent bio-indicators of habitat health and environmental degradation, especially in coral reefs and mangroves. It’s thought that around 1,000 species are found in the waters of Southeast Asia, although much more research is necessary to provide accurate statistics. Like much of our oceans, there is a tremendous amount we just don’t know. What is known is that they come in a huge variety of colours, and adapt well to changing environments. Bottom dwelling crabs will burrow under the sand and wait for their prey. Others have developed camouflage to match their surroundings, useful for hunting and being hunted!

P2-3-(2)Interestingly, in the United Kingdom, there’s great concern over one particular Asian species of crab, the Chinese mitten crab. And that’s because it is seen as a dangerous alien causing lasting harm to the environment. First recorded in the River Thames in the 1930s, scientists believe it arrived in the UK as tiny larvae, in ballast water in ships from the Far East. They took a long time to become established, possibly because of the river’s polluted state. Since the 1990s, however, numbers have mushroomed. They can travel over dry land and have spread to many other English rivers. Because there are no native freshwater crabs in the UK, species like the native crayfish, which is already in decline, are likely to be affected. Studies have shown that they can cause serious damage by burrowing into banks and earthworks along the rivers. And sport-fishermen in the London area say the crabs often hijack proceedings. As they are reasonably large (about three inches across), and are ravenous omnivores, it is feared they could both eat and out-compete vulnerable freshwater life forms.

Luckily they aren’t the largest of species. That honour goes to the Japanese spider crab which lives on the floor of the North Pacific Ocean. It’s been recorded as having a 12-foot leg span. That’s more than twice the size of your bed! On land, the largest species is the coconut crab, which can measure up to two and a half feet. It’s found on some islands in the Pacific Ocean. There are also a number of poisonous crabs whereby it’s possible to get blood poisoning from a claw pinch if the skin is broken. I suspect that would be the least of your worries though if the Japanese spider crab got hold of you!

Around Samui, most commonly you’ll find blue swimmers, which are relatively small with a sweetish taste. And a number of chefs will use black or mud crabs which have a better texture of meat and give an improved yield. Needless to say, the cost here is a lot less than at home. Aside from whole fresh crabs you’ll find Thai crab soup, spicy crab fritters with chilli and lime, crab curries and spicy crab cakes on a number of menus. All are definitely worth trying.

If you have a chance, visit one of the local fresh markets, where you’ll be able to see a whole variety of fish and crabs on display. They make wonderful eating and are nutritious and healthy. Meaning that later on, you can indulge in lots of stuff that isn’t, just to balance things out!

          

Johnny Paterson


 


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