WWF-Pakistan has clarified that the recent sea discolouration and glowing night-time waters reported along Karachi and parts of the Balochistan coast are caused by a natural sea sparkle bloom, not pollution. The sea sparkle bloom in Pakistan continues to draw attention from coastal communities and fishermen.
Fishermen reported bright bioluminescence and unusual green patches in the ocean, sparking fears of harmful algal blooms and rising coastal pollution. Environmental officials say the visual changes prompted confusion across several coastal neighbourhoods.
According to WWF-Pakistan, the discolouration is caused by Noctiluca scintillans, a naturally occurring organism commonly known as sea sparkle. Experts confirm this organism does not release toxins and is not harmful to marine life.
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Noctiluca scintillans can appear in multiple colours, including red, orange, green or even colourless forms. Along Pakistan’s coastline, blooms often appear green or orange depending on seasonal patterns and environmental conditions.
Scientists explain that although the organism is not green itself, its colour comes from an internal symbiont called Protoeuglena noctilucae, which helps it photosynthesize, multiply quickly and spread across vast ocean patches.
Because Noctiluca naturally produces bioluminescence, its presence causes the glowing effect visible in seawater at night. Similar blooms have been documented along coastlines of Yemen, Oman, Iran, Pakistan and western India in previous years.
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Experts point out that a major bloom in 2017 was visible from February to May and even appeared in regional satellite imagery. Researchers say this shows the phenomenon is well known and not unusual.
WWF-Pakistan’s Technical Advisor Muhammad Moazzam Khan confirmed the current bloom poses no toxicity threat. He added that no fish mortality has been reported anywhere along the Sindh or Balochistan coasts during this event.
Khan stated that blooms sometimes create a temporary unpleasant smell when they collapse, but this is a normal part of the natural biological cycle and not a sign of pollution or ecological damage.
The organisation emphasised that this bloom is being incorrectly linked to pollution in some reports. WWF-Pakistan stressed that it is a natural oceanographic event not caused by human activities or wastewater.
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However, WWF-Pakistan warned that Karachi’s chronic wastewater discharge remains a serious but unrelated environmental problem. Large volumes of untreated industrial and domestic waste enter the Malir and Lyari rivers daily.
Officials say this polluted water ultimately drains into the sea and contributes to long-term coastal degradation. They believe addressing wastewater management is essential for protecting marine ecosystems and coastal communities.
WWF-Pakistan urged government agencies to prioritise sewage treatment, effluent management and coastal water-quality improvement. Experts argue that consistent enforcement and investment are necessary for lasting environmental protection.
