Science - November 24, 2005

Student records damage to coral reefs

Eritrean PhD student Iyob Tsehaye is studying fisheries and fragile coral reefs in the Red Sea. Diving makes his fieldwork quite adventurous. He has a keen eye for reef damage and a wide variety of fish species. Wb interviewed him about his work.

Why are you studying fisheries in the Red Sea?
Along the Red Sea coast of Eritrea, increasing numbers of fish are being caught by international fishing boats and artisanal fishermen. However nobody seems to be concerned about the grave consequences of these fishing activities. I am collecting hard data that shows what exactly is happening.

Where and how deep do you dive during your fieldwork?
I dive mainly in and near the coral reefs. These are located around the more than two hundred islands along the Eritrean coast, belonging to the Dahlak archipelago. There are lots of opportunities for yacht cruising and scuba diving, not only for tourists, but also for scientists like me. I normally dive for about an hour and as deep as thirty metres. It’s really spectacular: the coral reefs house hundreds of fish species. I can identify most commercial fish like tuna, hammerheads, snappers and mackerel. There are also sharks in the Red Sea but I don’t worry as sharks usually do not go near the coral reefs.

What have you found so far on your dives?
I can see the physical damage being done to coral reefs. It’s probably not the artisanal fishermen with their small wooden boats who are causing the damage, but the big international fishing boats. Their trawlers drag their nets over the sea bottom to catch fish. These boats are actually not allowed near the coral reefs, but fishermen will do anything to keep their catches high.

Is over-fishing a problem in the Red Sea?
Artisanal fisherman started fishing again off the coast of Eritrea in 1991 after the long independence struggle. While the fighting was going on, fishing came to a halt and the fish population increased considerably. But the fish catches I’ve analysed are already indicating a problem. The commercially most interesting species are declining. These are the bigger fish, the top predators of the sea, like snappers, emperor fish and even sharks. Sharks are caught for their fins which are exported to Asia, ending up in soup.

What is your advice to the fishermen?
I advise the fishermen to diversify their catch. Instead of focusing on a few species, catch small pelagic fish like sardines and anchovies as well. In the end this will be better for the total fish population and the fisheries. But we must also acknowledge that small pelagic fish fetch far less than snappers or shark fins on the market. The government should therefore subsidise fishermen to encourage them to diversify their catch. Fishermen are already hampered by the high oil prices that have doubled.

Your study area is a long way from the Netherlands. Why did you choose Wageningen for your PhD?
I studied Marine Science at Asmara University in Eritrea, and our Biology Department works closely with the fisheries groups at Wageningen and Groningen Universities. I came first to do an MSc and now I’m continuing my PhD here, funded by Nuffic, the Netherlands organization for international cooperation in higher education. The knowledge on sustainable fisheries in Wageningen is a big help for me. / HB

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