Raw waste may trigger deadly jellyfish blooms

  • Nation
  • Wednesday, 28 Mar 2018

Thorough work: Research assistants combing the sea off Batu Ferringhi grid by grid with a special net designed to trap jellyfish. — Photo courtesy of Cemacs

GEORGE TOWN: Raw animal waste pouring into the sea from mainland Valdor will potentially cause destructive jellyfish blooms that create “dead zones” in the sea around Penang, a marine biologist says.

Jellyfish can increase and gather in such large numbers that they crowd out all other sea life, said Datuk Prof Dr Aileen Tan.

“When the animal waste is not treated first, the nitrogen, phosphorus and potassium it contains will create a burst of microscopic plankton in the sea.

“This will deplete the oxygen until fish cannot thrive, but jellyfish need very little oxygen,” she said.

Dr Tan added that marine researchers around the world have stressed that when the jellyfish population explodes, their tendency to catch all the fish larvae around them will make it difficult for fish stocks to stay sufficient for human consumption.

Marine life: A pail containing an Australian spotted jellyfish and box jellyfish of the Morbakka genus caught in the sea off Batu Ferringhi. — Photo courtesy of the Cemacs
Marine life: A pail containing an Australian spotted jellyfish and box jellyfish of the Morbakka genus caught in the sea off Batu Ferringhi. — Photo courtesy of the Cemacs

Universiti Sains Malaysia’s Centre for Marine and Coastal Studies (Cemacs) has been conducting studies on the jellyfish population in the state’s coastal waters since October last year.

Researchers comb the sea during neap tides with special netting and trap hundreds of jellyfish each time, including the deadly box jellyfish.

In Valdor near the second Penang bridge, an area measuring about 140ha has 43 pig and 57 chicken farms packed almost wall to wall with each other.

Dr Tan, the director of Cemacs, was appalled by the chemical analysis of the water in a canal flowing from the farms.

“It’s in extremely bad condition. No life can survive in that water. In those concentrations, when it dilutes into the sea, it will upset Penang’s coastal fisheries,” she warned.

The canal flows for only 4km from the edge of the farmland to a tributary of Sungai Jawi. Then, it is 8km to the sea.

It was reported that the ammoniacal nitrogen of the canal water about 2km from the farmland was 254ppm (parts per million) or 94 times higher than the level of a Class Five (severely polluted) river, as classified by the Department of Environment (DOE).

Dr Tan said she would raise the pollution readings with her counterparts in the Fisheries Department and DOE to discuss the impact of the animal waste discharge.

On Monday, The Star reported the woes of residents of a gated community just 100m from the farms.

The farms have been there for about 20 years, but the rapid growth of South Seberang Prai has seen upper middle-class residential projects approved within 5km of them.

State Environment Committee chairman Phee Boon Poh said the state was well aware of the issue.

“We want to develop South Seberang Prai because it is a vital urban-rural migration zone to relieve congestion on the island.

“The farmers have until the end of 2019 to adopt closed farming systems,” he said.

Bukit Tambun assemblyman Datuk Law Choo Kiang, whose constituency includes Valdor, called on government agencies to act.

“If the evidence is clear, then government departments and agencies should act without hesitation,” he said.

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