Remote sensing oceanography of a harmful algal bloom (HAB) off the coast of southeastern Vietnam

DanLing TANG, H Kawamura, Hai Doan-Nhu, W Takahashi , 2004. Remote sensing oceanography of a harmful algal bloom (HAB) off the coast of southeastern Vietnam. J. of Geophysical Research (Ocean).Vol 109, doi:10.1029/2003JC002045, 2004.


Harmful algal blooms (HABs) in the southeastern Vietnamese coastal waters have caused large economic losses in aquacultured and wild fisheries in recent years; however, there have been few oceanographic studies on these HAB events. The present study reports an extensive HAB off southeastern Vietnamese waters during late June to July 2002 with in situ observations and analyzes the oceanographic conditions using satellite remote sensing data. The HAB had high chlorophyll a (Chl a) concentrations (up to 4.5 mg m−3) occurring ∼200 km off the coast and ∼200 km northeast of the Mekong River mouth for a period of ∼6 weeks. The bloom was dominated by the harmful algae haptophyte Phaeocystis cf. globosa and caused a very significant mortality of aquacultured fish and other marine life. In the same period, sea surface temperature (SST) imagery showed a cold water plume extending from the coast to the open sea, and QuikScat data showed strong southwesterly winds blowing parallel to the coastline. This study indicated that the HAB was induced and supported by offshore upwelling that brings nutrients from the deep ocean to the surface and from coastal water to offshore water and that the upwelling was driven by strong wind through Ekman transport when winds were parallel to the coastline. This study demonstrated the possibility of utilizing a combination of satellite data of Chl a, SST, and wind velocity together with coastal bathymetric information and in situ observations to give a better understanding of the biological oceanography of HABs.


  • harmful algal bloom (HAB);
  • satellite remote sensing;
  • upwelling;
  • SeaWiFS;
  • chlorophyll a;
  • South China Sea

Shellfish alert as red tide hits Sabah waters

The Star, 3 Jan 2013

KOTA KINABALU: People are warned against eating shellfish or bivalves obtained from the sea following a red tide alert in Sabah waters.

Sabah Fisheries Department director Rayner Stuel said these included oysters, mussels, cockles and any type of clam-like seafood.

“A year-long Red Tide Monitoring programme conducted by the department with the state Health Department has detected the presence of paralytic shellfish poisoning (PSP) toxins in samples of bivalves from waters off certain parts of Sabah’s west coast,” he said.

High densities of the PSP-causative organism was found in samples of sea water from Kuala Penyu, Kota Kinabalu, including Gaya Island, Sepanggar Bay and Likas Bay as well as in the Papar, Putatan, and Tuaran districts.

Rayner said the numbers became so large and dense that they released a brownish red colour to the sea at times.

The types of sea life considered safe to eat include all types of prawns and crabs, coral fish and predatory fish.


Rosnah: Refrain from consuming shellfish

7 Jan 2013

Deputy Health Minister Datuk Rosnah Abdul Shirin advised people in Sabah to refrain from consuming shellfish and bivalve shellfish in the wake of the red tide. They are urged to seek immediate treatment at the nearest hospital should they experience symptoms such as numbness, dizziness, vomiting and breathing difficulties, particularly after consuming cockles. Tests on shellfish collected from areas affected with red tide revealed high concentrations of Paralytic Shellfish Poisoning (PSP) toxins, which may be fatal in extreme cases. State Health Director Dr. Christina Rundi confirmed on Saturday that two out of six people who were down with poisoning due to red tide after consuming shellfish have died. Christina said that all six patients were found to have consumed cockles collected from Sepanggar waters. According to hospital sources two patients, aged 14 and 9 suffered critical symptoms of severe anaphylactic shock and were diagnosed with PSP. Both passed away on January 2nd and January 4th respectively. Sabah Fisheries Director Rayner Stuel Galid explained that samples of seawater taken off Sepanggar showed a toxin reading of 6,000 Mouse Units (MUs). “The level is evidently very high because a reading of 400 MU is already toxic and dangerous,” he said. The red tide phenomenon has also been detected in waters off Papar, Putatan, Kota Kinabalu and Tuaran as well as Sitompok Lake in Kuala Penyu. Rayner echoed Rosnah’s call in urging the public to abstain from eating cockles, shellfish and small fishes. “Deep sea fishes, squids and crabs can be consumed but they must be cleaned thoroughly and the gills must be discarded,” he said.

Source: Insight Sabah