KARACHI, Oct 7: A 1.6-metre-long bramble shark (Echinorhinus brucus), a rare species, was caught in the Indus Swatch (offshore water off the Indus River) by fishermen and was brought to the Karachi fish harbour on Monday.

“It was sold out to fish meal manufacturers soon after its arrival at the harbour since the species has little commercial value,” said Mohammad Moazzam Khan, technical adviser (marine fisheries) of the World Wide Fund for Nature-Pakistan, adding that his staff identified the species by its purplish colour and denticles.

Mr Khan, who collected the first specimen of bramble shark in Pakistan, said that the species was usually found in the offshore waters up to a depth of 900 metres.

“The weird looking shark is of a rare occurrence in Pakistan and had been reported about eight times in the past. It was first reported in Ormara, Balochistan, in 1984 which was about 2.5m long caught with a handline. Since then this species has been caught by fishermen using trawl net or bottom set gillnets,” he said.

Bramble shark, according to Mr Khan, has a wide distribution in tropical and subtropical waters of the Indian, Pacific and Atlantic oceans and also in the Mediterranean Sea. In the Arabian Sea, it is known from Pakistan, Oman and India. It is a comparatively rare and sluggish shark which is found in continental shelf and slopes in these countries.

The shark feeds on a variety of food, including other small sharks, fishes and crabs and its litter size ranges between 15 and 26.

Explaining the Indus Swatch, he said that when the Indus, like all major rivers, entered the Arabian sea, it formed the world’s second largest submarine fan which had a deeply incised canyon known as the Indus Swatch. “This canyon starts close to the delta coast, about 3.5km from the mouth of the River Indus. It has a maximum depth of 1,030m. It is about 185km long and 8km wide. The Indus Swatch is an important fishing ground, especially for sharks. Because of unreliable depths in the area, trawling is usually not done in the area. Long lines and handlines are preferred gears in the area,” he said.

Commenting, Rab Nawaz, director of WWF-Pakistan, said: “The occurrence of rare shark species in Pakistan is a good indicator of our coastal and offshore waters’ biodiversity. There is a need to document the country’s marine fauna and flora as information about marine biodiversity is highly limited. A distant relative of this species, pelagic stingray (Pteroplatytrygon violacea) was earlier reported by WWF-Pakistan.”