Tag Archives: short-finned pilot whale

Whale and Dolphin Strandings and Oil and Gas Exploration in the South China Sea

In May of this year CNOOC reported a mid-sized oil field discovery, the Liuhua 20-2 field, in the Eastern South China Sea. Liuhua 20-2 is located in the Pearl River Mouth basin of the South China Sea, at an average water depth of about 390 m. The discovery well (LH20-2-1) was drilled to a depth of about 2,970 m.

This is only the latest South China Sea oil and gas field to be opened. In the last decade a large number of fields have been discovered, explored and commercially exploited. Hong Kong in fact receives some of its gas via a direct pipeline from a gas field southeast of Hainan Island.

Oil and gas prospecting, however, relies on seismic surveys. This involves sending powerful sound or shock waves through the water to the seabed to measure and analyse the echo received back. For the echo to give valuable data on lower rock layers they must be powerful enough to penetrate through thick sediment and into the rocks below. There are a few ways that can be done some including TNT or electricity to create imploding plasma bubbles. But the result is always a loud sound or explosion.

Oil and gas exploration in the South China Sea (via Energy-pedia, May 2014)

In the last few years Hong Kong has seen a number of more unusual whale strandings including deep-water species like sperm whales, Pygmy sperm whales and short-finned pilot whales, as well as other whales normally rarely if ever seen in Hong Kong such as Omura’s whales. Toothed whales rely heavily on echolocation (seeing by sound) for navigation, so the idea arises whether increased seismic survey activity in the South China Sea is part of the cause for these strandings.

Unfortunately, I am not aware of any scientific investigations into the effects of seismic surveys on whales and dolphins in the South China Sea. Research in this area is very difficult because it is hard to track whales and dolphins in the first place, and because their navigation sense is poorly understood. There are also multiple possible reasons for strandings, including disease and injuries so making a causal link between seismic surveys and whale strandings is very difficult even in the best of circumstances. However, intuitively, it seems right to restrict the use of loud explosions in the habitat of rare marine animals with very sensitive hearing organs that are also essential for their navigation. Particularly as sound conducts much better in water than in air.

When I took part in a research cruise to the Weddell Sea in Antarctica (back in 2005) there was actually a restriction on even the scientific use of small seismic surveys for marine geological baseline research. Special permits had to be applied for from the relevant government ddepartments of participating nations – in the end the only country that granted a permit was Russia.

There are also (as far as I am aware) reasonable restrictions on using seismic surveys in the North Atlantic by Europe, the U.S. and Canada, that require observers to check (as far as possible) that no whales are in the area before the survey starts.

I am not aware of any such restrictions in the South China Sea, although my knowledge of PRC laws and regulations is poor and perhaps such rules exist after all (feel free to point out any errors in the comments below).

News: Pilot Whale in Spotted Hong Kong Harbor

A pilot whale was spotted yesterday morning (13th January 2015) at about 10 am off Tsim Sha Tsui between the Ocean Terminal and the busy China Ferry Terminal. Unnamed experts identified the apparently 3-m long whale as short-finned piloit whale (Globicephala macrorhynchus), which can grow to 6.5 m in length (figure quoted by The Standard) – but you will find estimates of up to 7.3 m in the literature. That would make this whale a juvenile or young adult. It lingered there for approximately 3 hours before dissapearing again.

Short-finned pilot whales are rarely seen on their own and tend to appear in groups of 10 – 30 sometimes up to 50 individuals and prefer deep-water. A juvenile lone short-finned pilot whale in Hong Kong’s shallow waters is therefore sadly no cause for cheer – more of a sign of being lost, injured or sick. The video footage (below) seems to show some surficial insuries to both sides of the head as well as the lower frontal edge of the dorsal fin.

You can see more footage in the article from Apple Daily’s local news site.

Some readers may remember a similar-looking species of whale – the false killer whale – showing up at about the same time of the year in 2014 near Kwai Tsing Container Terminal. In that instance it was a group of possibly up to 100 individuals which later on left Hong Kong waters again. There is some video footage of that event I posted here.