The WWF-Pakistan on Friday expressed concerns over sudden gush of mass blooms of free organism on the country's coastal waters. It said that a foul smell was reported in different parts of the city on last Wednesday, May 31, particularly felt in South, East and Central Districts along the coastlines. No immediate reason is seen to attribute it to the cause of the stench. However, WWF-Pakistan believes the decaying of small plank tonic dinoflagellate called "Noctilucascintillans".
"Blooms of Noctilucascintillans (commonly known as sea sparkle) occur at least twice a year. However, in some years, the intensity of such blooms increase substantially and result in fish mortality in some cases," technical advisor (Marine Fisheries), WWF-Pakistan, Muhammad Moazzam Khan said.
He added that onset of the monsoon results in a change in currents pattern and due to this Noctiluca start dying and result in an atypical odour. "The smell is not generally harmful," he said. The WWF-Pakistan said that mass bloom of this small free floating organism was reported from the Arabian Sea including the Pakistan coast. It is reported that the bloom was more prominent along the Pakistan and Oman coasts. According to WWF-Pakistan, the green bloom along Pakistan's coast started appearing in February 2017 and continued till late May with a peak in March and April. In some areas the sea water even turned into green soup.
Noctilucascintillans blooms have been reported from Pakistan's coast on many occasions. They occur in two forms, ie orange (or red) and green, which sometimes result in the mortality of fish and shellfish. During the current year the mass scale green bloom occurred but no mortality of fish or shellfish has been reported from Pakistan so far. However, mass scale mortality of pelagic shrimp and associated fish was reported from Oman coast.
Fishermen reported discoloration of water during the last five months. A reversal of currents and wind patterns under the influence of the southwest monsoon in late May has resulted in the decay of the blooms, which caused the atypical stench in coastal areas of Karachi. "The frequency of such blooms is increasing in Pakistan which may be attributed to climate change. However, other anthropogenic factors may be the cause of such blooms," Senior Director Programmes, WWF-Pakistan, Rab Nawaz said.