Day 3: 30 April 2015 (Thursday): spotted dolphins again and made history
by Dr Alfonso Lopez
It was extremely sunny this morning when we set off around 7am. But within just two hours, at about 9am, a storm started to build up at the south-eastern side of the north lake.
Despite the gloomy weather and pending storm, we kept a keen lookout for Irrawaddy dolphins. Upon reaching the area where we spotted dolphins on Day One, we found a half-eaten spotted catfish floating on the surface. The catfish had what appeared to be, dolphin bite marks on the carcass. This species of catfish is commonly found in Irrawaddy dolphins’ stomach contents.
This was promising news that the dolphins may be close!
At 10am, the skies opened up and the heavy downpour made it very difficult to spot the dolphins. Due to the storm and for safety reasons, the aerial survey had to end prematurely without finishing all the transect lines.
Just when we thought we might end up empty handed, we received great news from Team 2: they spotted dolphins at the same area we saw them on the first day!
There were over 10 Irrawaddy dolphins in the pod and most of them were swimming in pairs. Our boats approached the pod very slowly, and even turned the engine off to avoid startling them.
But once they realised the proximity of our boats, they swam away and separated into two groups; one group swam to the east while the rest headed north.
The first ever photo IDs of Irrawaddy dolphins
Luckily, the team was quick to react and managed to snap photos of four of the dolphins with their dorsal fin breaching the water surface. These images serve as photo identification (photo IDs) as the dorsal fin is unique to each dolphin. Just like fingerprints that allow us to identify individual people.
Photo ID is a technique used to recognise individual animals by documenting the individual’s physical features. In the case of dolphins, the scars, shape and size of the dorsal fin will point us to specific individuals. So that when they are seen again, aspects of their life history can continue to be documented.
By studying individuals repeatedly over a prolonged period of time, we will be able to uncover movement patterns, social dynamics, and even life spans of these dolphins.
Due to the shy nature of Irrawaddy dolphins it is a challenge to take clear photo IDs. In fact, we are making history and this is the first time anyone has managed to do so. Great job everyone!
Presentation by Department of Marine and Coastal Resources (DMCR)
After lunch we had a great presentation on the current status of Irrawaddy dophins in Songkhla lake from Mr Somchai Mananansup (Director of DMCR Songkhla Lake), and Dr Kongkiat Kittiwattanawong (Endangered Species Unit, DMCR of Phuket Marine Biological Center (PMBC)).
Less gill nets, more dolphins
As mentioned previously, fishing gear, especially gill nets, was one of the leading causes of dolphin death. Gill nets were used to catch the giant Mekong catfish which was introduced to the lake by the Department of Fisheries 10 years ago.
Realising the issues associated with the gill nets, the Thai government took action and bought the nets from the local fishermen. A drastic decrease in dolphin mortality was recorded and so far in 2015, there has only been one reported death of an Irrawaddy dolphin.
Here’s a surprising fact for you:
Do you know that to date, 2,000 gill nets have been destroyed? If you were to place all these nets together side by side, they would easily measure over 10 kilometres!
It is easy to see how these nets have had a major impact on the population numbers of Irrawaddy dolphins.
Today has been a very fruitful and encouraging day. Hopefully, tomorrow will be just as rewarding.
Follow the team on their trip
- Save the Irrawaddy Dolphin Project: Day 1
- Save the Irrawaddy Dolphin Project: Day 2
- Save the Irrawaddy Dolphin Project: Day 3
- Save the Irrawaddy Dolphin Project: Day 4
- Save the Irrawaddy Dolphin Project: Day 5