One of the fun things about research in the tropics is trying the food and drink in the different countries you visit. Some of my favourite places to eat in Malaysia are the seafood markets. In the bustling town of Kota Kinabalu in Sabah there is a ramshackle mass of stalls that fringe the seafront. Every available space is crammed with a multicoloured selection of rickety plastic tables and chairs. The air is smoky from the open-air barbeques, offering everything from ayam laut (sea chicken – a leaf-shaped white fish) to prawns and whole baby squid. Some of the more up-market of these eateries even boast a selection of giant salt-water tanks, each alive with fish and other creatures that swim around their sparse homes, waiting to be chosen as someone’s dinner.
From a biologist’s point of view, looking in these fish-tanks is a bit of a double edged sword. On the one hand you see some amazing sea creatures, but on the other many of the species on offer are far from sustainably harvested and illustrate the impacts of overfishing in the region. Here there will be a deep-sided container full of cockles, there a shallow, algal-covered tank filled with giant prawns, their antennae waving above the surface as if trying to attract your attention. A popular food always seems to be mantis shrimps. These look like elongated lobsters, are striped like humbugs and have long antennae and beady, protruding eyes. The most obvious difference is with the claws. Unlike the heavy pincers of lobsters, mantis shrimps have a pair of curved and wicked-looking scimitars, which the animal can extend with amazing speed to harpoon its prey, just like a praying mantis does on land (for some beautiful footage of a mantis shrimp in action, click on this link). This strike can be so strong that they have even been reported to break the front of a fish-tank. Perhaps for this reason and because they would probably eat each other, the tanks containing the mantis shrimps are filled with plastic bottles, each with a shrimp inside. The mouths of these bottles are just too small for the shrimps to escape: a bit like a crustacean ship-in-a-bottle. If you can overcome your guilt and order one, they are brought to the table, roughly cut into quarters and fried in a sweet, sticky sauce. They taste almost exactly like prawns, although a bit stringier in texture. An advantage is that you get to examine their amazing front limbs more closely and see how each spine fits neatly into a sheath on a corresponding section of the leg.
Sometimes the animals on offer come as a surprise. The last time I visited one of the markets, I was amazed to find some of the giant coconut crabs for sale, each hanging from a thread tied around its middle and slowly revolving in the humid air. These slightly-freakish looking animals are closely related to hermit crabs, but rather than borrowing a succession of shells, these have hardened carapaces of their own. Each was about twenty centimetres long, reddish and spotted with yellowish dots, like a strawberry. Although marine in origin, they spend their lives out of the water at the top of the beach, where they scavenge for food. Anecdotal reports claim they can climb up coconut palms and use their claws to cut through the stem of the nut so it falls to the ground where they can feed on it. Whether they can really do this or not, their claws are extremely strong and you certainly wouldn’t want one to nip you. I’d never seen them for sale before so I asked one of the stall owners about them, who told me that they had become very popular and expensive. They aren’t found in Borneo and the ones I saw had been imported all the way from the Philippines.
Some of the bigger tanks in the market contained the larger reef fish: groupers and wrasse. I even saw a young Napoleon Wrasse: one of the very largest reef species, now rare due to overfishing. This one was small: only about thirty centimetres in length – about as long as its tank was wide. In the wild adult males can grow to over a metre and are easily distinguished from other species by a large hump, like a quiff, that jut out from the front of their head. Something about this peak, together with their pouting lips makes them resemble a fishy Elvis Presley, but without the hips. Helen Scales, a researcher in Cambridge, studied this species for her Ph.D. and discovered how severe the effect of overfishing has been in Malaysia. Because they are long-lived and slow to reproduce, their numbers have declined dramatically and fishermen are forced to catch smaller and smaller fish over an ever-expanding area. As more expensive and profitable species get harder to find, so smaller and less profitable fishes are chosen, which then also decline, eroding the reef diversity piece by piece.
If you would like to find out more about issues relating to conservation, we have several relevant courses coming up at Madingley:
Helen Scales is also a tutor at the Madingley and is running a course on marine conservation next year; a must for anyone interested in the marine environment: