`Whale sharks frequently caught as bycatch`

July 13, 2010

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KARACHI, July 12 Studies and observations indicate that the Arabian Sea is serving as a feeding, resting and breeding ground for the whale shark that arrives at the Karachi fish harbour as a bycatch once or twice a month, said director general of the federal government's marine fisheries department Dr Mohammad Moazzam Khan while talking to Dawn recently.

Marine officials at the harbour, according to Dr Khan, had been constantly monitoring the occurrence of the whale sharks along the Karachi coast for four years, though the collection of an in-depth morphological data of the species was initiated in 2008. Dr Khan, who also worked in the Balochistan fisheries department for many years, was speaking in the context of the recent incident off the Hawkesbay beach where a whale shark died after it became entangled in a net.

The fish was chopped up into small pieces and its meat was sold off the very next day by local fishermen while no government institution could initiate any conservation effort.When asked about that particular incident, he said that although he himself was not in the city, his team visited the site and there was a plan to take some of its samples for examination.

“But this, unfortunately, couldn't be done. Fishermen didn't wait and sold its meat right away. However, this one incident does not undermine the significance of the efforts we have been making for many years,” he said, adding that at least 18 frozen specimens taken from the same species were present in the department's laboratory while a few had been sent abroad.

“The purpose is to determine the size of the current stock, its migration patterns and details regarding its habitat,” he said. About the presence of the fish near the coast, he said that the filter-feeding shark also ate sergestid shrimps which were found in large quantities in the summer along the coast. “They not only feed and breed here, but also have been found to be basking in the open sea off the Cape Monze area. Their presence is also indicative of the good health of the waters.”

'Giant innocent fish'

Regretting the killing of the species, Dr Khan stressed the need for creating awareness of the significance and conservation of the whale shark which he referred to as “a giant innocent fish” with no commercial significance for local fishermen.

“They are generally harmless to humans. The hunting of the fish stopped 50 years ago. At that time, it was hunted with the help of harpoons. Now, it is killed only after being caught as bycatch and this happens once or twice a month at the Karachi fish harbour. The longest whale shark so far recorded by us at the harbour was of 20 feet.”

He also termed the practice of using the whale shark's liver oil to polish boats tragic.

“Instead of extracting oil from the liver of the slow-breeder fish whose number has greatly declined over the years, fishermen can use lubricants to smoothen their boats,” he said.

A number references to the species, he pointed out, were found in old writings. For instance, 'Shark fishing in Kurrachee' by Dr Buist printed in 1850 and articles printed in Sindh Journal of Natural History (1930s) and old editions of Proceedings of Zoological Society of London.

Explaining some unique features of the fish, he said that there had been a lot of confusion about how whale sharks gave birth and finally it came to be known that embryos developed inside eggs and the eggs remained in the body and the females gave birth to live young.

“There is no placental connection and the unborn young are nourished by egg yolks. The huge mouth has very small teeth that are not used for feeding.

“Unlike other fishes, sharks have no bones. It's called a whale because of its huge size. The skeletons of sharks are made of cartilage. I was surprised to read statements of some wildlife experts talking about preservation of the species' skeleton when the incident occurred,” he said. According to Mr Khan, around 64 types of sharks have so far been reported in Pakistani waters which include almost all the dangerous predator fishes except the most lethal one, the great white shark.

The whale shark is listed as vulnerable by the IUCN (International Union for Conservation of Nature).