Longnose Filefish show reef health

I took two beginner divers for their first dive experience for a little underwater excursion on the Mnemba Housereef on the northwest side of the island. We had just gone down on the edge of the reef when I spotted two, about 8 cm long Longnose Filefish 'hovering' above a little table coral.

Their bright green color with orange dots on the body and orange stripes on the head makes them look like little clowns. It was not just their color that made this sighting is so exciting, the presence of this species means that the house reef is in excellent health.

Longnose Filefish feed almost exclusively on the polyps of acropora table corals, and without an abundance of these corals they can not survive. In 1998 the acropora table corals died almost all over the world because of an extreme raise in water temperature caused by the El Nino. The reefs around Zanzibar and at Mnemba were not spared although got away with relatively less damage than many other reefs in other areas.

The life Acropora table corals were all but completely gone and the longnosed filefish disappeared with them. Now seven ½ years later the corals are healthy and abundant again to get Longnose Filefish to return on the reef.

Jan Christiaens

Posted: Mnemba Island by CC Africa, Date: 21 November 2006