Wednesday, February 19, 2014

Sousa chinensis mum and baby: Another bycatch from Paloh

The female Sousa chinensis by-caught in Paloh, pic by Taufik

17 February 2014

Februanty Purnomo and I were packing our stuff for one night overnight at Temajuk by the border of Sarawak when Dwi Suprapti, DVM rushed in, declaring that a fisher just caught a dolphin in a village nearby. We dropped our overnight stuff, grabbed our GPS, camera and note book, and drove out to Guntung, about 20 min drive south from the WWF Paloh basecamp where we had been staying since last Saturday.

We arrived about an hour too late, apparently, for when we arrived there, the dolphin had been cleanly dissected by the locals for personal consumption, leaving only about 30x30x30 chunk of meat in whitish skin on the ground. Thanks to technology tho, even fishers nowadays have smartphones. One of them produced his Blackberry and showed us the picture of the dolphin. As I suspected from the white skin, it was a Sousa chinensis (Indo Pacific humpback dolphin).

We asked permission to collect samples, it was granted. We collected a piece of blubber for toxicology, a piece of skin for genetic analyses and a piece of meat for good measure. Then we walked to the beach to check the boat and gillnet specs. We found that approximately 4 sqm of the 2.5” gillnet was gone as the result of the entanglement. The fisher, 40 years old Miraldi, said it was the first time he caught this species, tho he often saw it milling around the shallow waters of his village. From the dolphin’s position on the boat, we concluded that the Sousa was about 2.5 m long. After examining the boat, we walked back to the village, passing by a small river on our left side. Agri Aditya of WWF saw it first: a weird floating object, which turned out to be the object of desire of any vets and marine biologists dabbling in stranding and bycatch cases. An almost complete set of the Sousa’s internal organs.

The internal organs of the Sousa chinensis

Agri fished the organs out of the water; we immediately realised it lacked the heart and liver. It had the lungs, stomachs and intestines tho (and later we found out: also the kidneys and spleen). Then we found another item: the floating fetus, still wrapped in its amniotic sac.

The case is clear now: we had to abandon the Temajuk bycatch survey and stayed at Paloh to conduct necropsy on the Sousa mum internal organs and her fetus.

After shopping for necropsy tools (stationery cutter replacing the scalpels, etc), we started the necropsy at around 8pm last night. We started with the gross examination of the lungs, including measurement. We then proceeded to the trachea and the three stomachs. We skipped the intestines because it was already green and it surely would smell bloody awful. We found fish thorns in the pyloric and fore stomachs; that dolphin had been eating before it was by-caught, but not sure the time interval between her finished eating and being caught. I’d say she had finished digesting the meal before being caught. We also found froth/foam inside the airway and lungs.  However, because we found the internal organs already floating on the river, we’re not certain that the froth was post-mortem or ante-mortem.

The fish thorns and otolite inside the fore stomach

After finishing with the kidneys (looked healthy with pronounced granules), we proceed to the fetus. We felt the fetus before Dwi cut the amniotic sac. Seemed like it had developed into a complete individual. After Dwi cut the amniotic sac, we found that the fetus was indeed ready to be born in a few days (I’d say). Everything was complete, externally. The total length from snout to fluke is 75 cm, about ¾ of the usual newborn length of a Sousa chinensis (approx. 1m). The teeth have not developed yet. It was a boy. It might have passed its third semester when the mum died…

We secured the baby inside the small WWF freezer in Paloh. We are going to bring the baby to Pontianak today, which is about 10 hours away. We hope that the baby will still be frozen by the time we found a larger freezer in Pontianak.

From the mother, we have secured the blubber, skin sample, and also samples of lungs, kidneys, spleen, trachea, and stomach (the pyloric, I think). We will ship the samples to IBRC Bali. We will also divide the genetic sample for the LIPI Lab in Jakarta. We don’t have a scale, so we didn’t weigh the baby. We also didn’t weigh any of the organs. We couldn’t secure the skeleton, it was already chopped along with the meat.

What are the lessons learned from this event?

Well, first and foremost: bycatch is bad for the cetaceans and the communities. The animals are dead, the fishers got the nets destroyed. Even the fisher himself felt sorry when he realized a baby was inside the mother, and the baby was dead because of the bycatch. 

Second: we must find bycatch mitigation techniques for Paloh and surroundings asap.
Third: for necropsy, we need to have good tools ready to use in major bycatch areas. Dwi and I (and our team) had to improvise with stationery cutters as scalpels, and those are not the best tools, particularly if we have the complete specimens.

Fourth: a standby freezer at major bycatch areas would be grand to store specimens, particularly for later necropsy usage. 

Fifth: bycatch is baaaaaad…

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