Squid beaks, plastic debris among contents found in Jurong Island sperm whale’s belly: Study
SINGAPORE: Jubi Lee, the 10.6m female sperm whale that was found off the coast of Jurong Island in 2015, lived on a diet of squid, a study has shown.
Researchers from the Lee Kong Chian Natural History Museum found more than 1,800 beaks from at least 25 cephalopod species, mainly squids, in the whale's belly. There were also remains of fish, a mud lobster, and several "peculiar" bioluminescent animals known as pyrosomes.
Jubi Lee's belly also contained plastic drinking cups, food wrappers and a plastic bag, the study led by museum mammal researcher Marcus Chua concluded.
Even though the plastic found in its stomach was not “large or copious enough to have resulted in death”, the discovery adds another account of plastic debris found in whales across oceans since the 1970s, the study said.
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The drinking cup and food wrapper that were found appeared to be from Indonesia.
“With the amount of marine litter (including plastic debris) generated by Southeast Asian nations equalling or exceeding global averages, this may be of conservation concern to threatened marine species, such as the sperm whale, in the region,” the paper said.
“The ingestion of plastic debris has been known to result in the death of sperm whales due to gastric blockage or rupture,” it added.
Mr Chua told CNA: "This certainly confirms what we have been hearing about in reports that the oceans are polluted with plastic and it is affecting wildlife.
"It is also a sober reminder that we have to manage our use and disposal of plastic."
THE WHALE'S ORIGINS
An analysis of its diet, genetics and regional water conditions told the researchers that the sperm whale probably originated from a pod in the Southern Indian Ocean, close to the Cocos (Keeling) Islands or Indonesia.
Using a modelling technique, Mr Chua’s team was also able to approximate that the whale died to the west of Malaysia and free-floated to the southwestern coast of Singapore.
The team also observed that that the whale had spinal injuries and a large gash on its back, suggesting that it was struck by a ship.
When it was found, researchers immediately went to work salvaging the carcass for further examination by collecting DNA samples and its gut contents.
"For example, questions such as where did she come from? How did she die (was it something she ate, an injury, or disease)? And how did she end up there? From there, we made sure we collected and preserved parts of the whale that may provide clues to the questions," Mr Chua said.
"For areas outside our expertise, we collaborated with scientists in the National University of Singapore - Dr Ooi and Dr Tay for the coastal modelling to determine how her carcass drifted - and overseas experts like Dr Kubodera, who is a squid researcher from Japan," added Mr Chua, who described the research process as "humbling and daunting".
"While each aspect sheds a little light about the whale, together they help form a clearer picture about what could have happened in her final moments. Seeing it come together was really interesting but also made us aware of how tragic the end was," Mr Chua said.
The skeleton of the whale was preserved and is now exhibited at the Lee Kong Chian Natural History Museum.
The animal is the first sperm whale found in Singapore waters. Sperm whales are classified as a vulnerable species by the International Union for Conservation of Nature.