Malaysia: Possible reason for the fish deaths

19th March 2015;

A series of field tests by a combined team from the Department of Environment and Sabah Fisheries Department suggest dissolved oxygen and red tide measuring hundreds of thousands per millilitre water in the Kolombong monsoon drain to be the cause of death of hundreds of thousands of fish last Saturday.

“Any red tide density of 100,000 per millilitre water and above is considered bad,” an aquatic biologist told Daily Express.

But further tests conducted Monday morning showed the dissolved oxygen level read 5-6 parts per million, salinity read about 10 parts per thousand (compared normal ocean salinity of 34-35ppt) while the pH read about 6, according the DOE and Fisheries officers on site.

Red tide is a common name for algae bloom meaning large or dense concentration of singled-celled aquatic micro-organisms called dinoflagellates or phytoplanktons in scientific jargon.

And the level of dissolved oxygen in water in this case plunged to zero last Sunday, is a key parameter used to assess the effect of red tide on water quality and aquatic life.

But algae bloom is usually fuelled by too much nutrients in the water (called eutrophication by aquatic biologists). Algae or phytoplanktons are microscopic plants which under normal circumstances, oxygenates and enlivens water as a by-product of photosynthesis.

Oxygen also diffuses from the atmosphere into water surfaces where microscopic bubbles of it get mixed in between water molecules and fish, crabs, and worms remove those bubbles of dissolved oxygen and pass it into their blood as the water moves through their gills.

The problem with algae bloom is there won’t be enough filter feeders or fish fry to eat up the excess and so much of this high density biomass die and sink to the bottom where decomposition by bacteria uses up lots of dissolved oxygen until little or none is left.

Scientists generally agree that most fish need about 5mg per litre of dissolved oxygen to live and thrive especially spawning migratory fish and eggs need about 6mg/litre although size matters, like clams and worms need just 1 mg/litre, crabs and oysters about 3mg/litre.

But mass mortality of Tilapia (Oreochromis sp.) has been observed to repeat itself in the monsoon drains around Kota Kinabalu during hot and dry spells, like the current one, when hotter water can hold less oxygen, it is believed.

On the other hand, mass Tilapia deaths generate little or no public shock or even concern since the water quality of public drains across the capital city is generally so foul and polluted that few people considered them desirable and unsafe to consume.

Source: Daily Express

Malaysia: Possible reason for the fish deaths

Thousands of dead fishes at Pasir Ris
By Ria Tan, 28th February 2015;

Thousand of dead fishes washed up at Pasir Ris beach today. Sean Yap also shared photos of dead fishes found on the same stretch of western Pasir Ris that I surveyed.

What is causing this mass fish death? Is it harmful to humans?

There was a line of dead fishes along the area I surveyed. Some had a thinner line.

In the part of the shore outside Pasir Ris Park proper, there was a bigger build up of dead fishes. But even here, the cleaners were trying hard to clear up the fishes. I also met Dixon who was cycling in the area and went down to the shore. I asked for his help to go down the entire length of Pasir Ris Park to see how widespread the dead fishes are. Thank you Dixon!

Read More

Source: Wild Shores of Singapore

Fish farm proprietor Lee Boon Hock, 30, picking up one of the dead ‘ikan merah’ (Red Snapper) (Lutjanus sp.) at his farm in Tanjung Kupang.

Malaysia: Department of Environment looking into mass fish deaths
By Yee Xiang Yun and Kathleen Ann Kili, 17th February 2014;

The Department of Environment (DOE) is carrying out a study to find the cause of the massive fish deaths in the waters off Tanjung Kupang, near here.

The deaths occurred about 3km from a land reclamation project but the department said no industrial pollution or oil spillage were detected in the waters.

“The deaths could be due to the red tide phenomenon or change in weather, which causes an overgrowth in plankton, resulting in the lack of oxygen in the water,” a DOE spokesman said yesterday.

“Red tide” is a common term used for a harmful algal bloom, or HAB, which occurs when colonies of algae grow out of control while producing toxic or harmful effects on people, marine life, animals and birds.

It was reported on Friday that at least 10 fish farms and 250 traditional fishermen were affected by the death of the fishes, initially believed to be due to the off-shore land reclamation works.

The state government said it is also investigating the incidents.

Mohd Khairi Malik, the political secretary to Johor Mentri Besar Datuk Seri Mohamed Khaled Nordin, said the state government expects to receive a report within this week from the Environmental Investi­gation Agency, the organisation committed to investigating and exposing environmental crime.

“The state government will halt the project if it is causing the fish deaths,” he said.

Meanwhile, state-owned Kum­pulan Prasarana Rakyat Johor Bhd denied the mass fish death was caused by the nearby reclamation works.

KPRJ executive vice-chairman Datuk Md Othman Yusof said the project, which began on Jan 22, had followed all regulations set by the DOE and that the department would conduct checks from time to time to ensure they (the developers) stick to regulations.

Source: The Star

Malaysia: Department of Environment: ‘Red tide’€™ phenomenon believed to be cause of mass fish deaths

16th February 2014;

Last Thursday’s mass fish deaths, including those farmed in sea cages off Tanjung Kupang, are believed to have been caused by the ‘red tide’ phenomenon.

The Department of Environment (DOE), in a statement here today, said the phenomenon was caused by excessive plankton resulting in reduced oxygen in the water.

It said DOE which conducted preliminary investigation on the day of the incident, found no contaminant or oil spill near the venue.

“A similar incident also occurred on Dec 28, 2009. Nevertheless, DOE will continue to monitor and take enforcement measures on the premises in Gelang Patah,” said the statement.

It also said the Johor Fisheries Department had been referred to identify the exact cause of the fish deaths through the analysis of fish samples.

Meanwhile, Kumpulan Prasarana Rakyat Johor (KPRJ) denied that offshore land reclamation work conducted by the company had caused the death of an estimated four tonnes of fish.

Its executive deputy chairman, Datuk Md Yusof Othman said the reported fish deaths were not just happening in the reclaimed areas but also in Singapore.

According to him, the reclamation work began on Jan 22, involving a 0.4 hectare area.

“If the fish were dying due to reclamation work, why are they only dying now and not a day or two after we started work?,” he asked.

The incident has affected 10 fish farms and 250 traditional fishermen.

Source: Bernama

Malaysia: Department of Environment: ‘Red tide’€™ phenomenon believed to be cause of mass fish deaths