Bulletin 25 March 1985: Close Encounters of the Electric Kind

Close Encounters of the Electric Kind

The 6th December 1984 was a coolish day but the underwater scene became hot with electric current as the author came into contact with Torpedo fuscomaculata, a fish of the family Torpedinidae. The unexpected meeting was off the Dibba coastline in the Gulf of Oman, at a depth of about nine metres.

Torpedinidae generate electrical charges from two organs, located as shown in the sketch. The initial discharge is the most severe at several hundred volts -- equivalent to touching the spark-plug connection on a running outboard engine. As the electric organs take time to recharge, subsequent discharges are weaker. The charge is used to stun small sea creatures prior to eating, but it also acts as a deterrent against most predators except the larger sharks which readily feed on Torpedinidae.

Known as the Electric Ray ('lakhmah' in local Arabic), Torpedo fuscomaculata is often found half-buried in sand at relatively shallow depths. It is reputed to be on both UAE coastlines but I have only ever seen it in the Gulf of Oman. The species is shaped as in the sketch, with a yellowish-brown body and irregular dark blotches and speckles. The two dorsal fins and the tail are also yellowish in colour. A small breathing hole appears behind each eye. The species grows to a size of 45 cm -- measured across the disc -- though the one observed was less than half that width.

T. fuscomasculata is usually encountered in shallow waters with a sandy bed, but also under projections such as coral branches or, in my case, beneath a rusty iron grill. Lying partially covered the fish is well-camouflaged from unsuspecting prey. It is also a curious species. On one occasion I was approached by one but it didn't seem unduly bothered even when gently prodded.