Tuesday, March 10, 2009

Neonatal whale shark found in the Philippines

Shark news wires and internet sites have been set buzzing over the last few days by the news of the capture and release of a baby whale shark near Donsol in the Philippines.

This is the account from the Philippine office of the World Wide Fund for Nature:

“On the morning of March 7th, word reached Nitz Pedragosa, Donsol’s Tourism Officer, that a whale shark had been caught on March 6th in nearby San Antonio, a barangay of Pilar town, adjacent to Donsol. It was allegedly tied up, and being sold. Very quickly she sent Embet
Guadamor, a Butanding Interaction Officer (BIO) from Donsol, to inform the town’s Municipal Agricultural officer. Elson Aca, WWF’s Project Leader in Donsol, also came to investigate.”

“As they pulled up to the seashore an hour later, the team was met by Captain Berango, the Pilar police chief. They expected to see a giant animal helplessly
stuck, its tall dorsal fin and tail sticking out of the water. But there was nothing there. All they saw was a stick, stuck in sand, with a small rope leading away from it, into the water. Elson walked up to the stick and was amazed to find the smallest whale shark he had ever seen – a mere 15 inches long!”

All 38 cm of neonatal whale shark being measured, still tied to the red restraining 'rope'. Photo WWF Philippines

“The team freed the shark from the rope that was tied around its tail. After checking to see that the animal was unhurt, documenting the discovery, and measuring the shark, they transferred it into a large, water-filled plastic bag to allow it to swim freely while preparing for its release. Less than three hours after the report first reached Donsol, the response team was back on their banca, shark safely in hand. They took the shark out to deeper water, where it was less likely to get entangled in a fish net, and there – they set it free.”

The neo-natal whale shark released from its tether by the rescue team, photo WWF Philippines

The discovery of neo-natal (birth-sized) whale sharks is very rare, so much so that only 14 reports of whale sharks of less than one metre in length have been recorded in the scientific literature and almost all were taken by fishing activities of one sort or another.

However, one large pregnant female was caught in the Tawian fishery in 1995 and fully inspected by fisheries scientists Joung, and Chen. They found that the mother had over 300 developed embryos; most were in leathery egg cases and still had yolk sacs attached. They found the neonates were in three size classes 42–52 cm, 52–58 cm and 58–64 cm; the largest of the embryos were free of their egg-case and had no yolk-sac indicating they were ready to be released.

Bearing this in mind, this discovery in the Philippines of a pup of only 38 cm in length would indicate that it was a very immature pup and is unlikely to have been birthed ‘normally’….

So and how and why this baby whale shark has ended up in a fisherman’s net is something of a mystery but now it has a second chance at beginning a long life…

The full story is available on the WWF Philippines web site or from their global web site.