Every monsoon, thousands of seashells wash up on Karachi's shores. Here's why

Each year, sometime around June, Karachi’s beaches become crowded — not just with people, but also seashells, hundreds of thousands of them, spread across the shore in dense and clattering drifts. The sight leaves citizens intrigued, with many wondering if something was wrong. The same thing happened this June, as well. For the past few days, there has been discussion both online and offline regarding why this phenomenon occurs. Was it climate change or nature’s spectacle? The science and the fishermen tell a more layered story. A prelude to the monsoon The phenomenon is not new. A Dawn report dated July 17, 2009, noted that large numbers of white and yellow seashells had appeared on Clifton Beach overnight. Another Dawn report, dated May 21, 2016, reported that wave action dislodges shellfish, particularly Venus clams, locally known as “burgar”, from shallow sub-tidal habitats, carrying them onto beaches where they die and leave behind empty shells. The same event was also covered by The Express Tribune on May 22, 2016. Both news reports stated that the phenomenon is linked to the arrival of the monsoon. An Aaj News report dated July 10, 2024, also noted that marine experts continue to identify June and July as the recurring seasonal window for this phenomenon, though it added that rising pollution levels may be contributing to higher rates of marine mortality, leading to larger volumes of shells washing ashore in some years. Majeed Motani, president of the Pakistan Fisherfolk Forum, who has decades of fishing experience, confirmed this. The phenomenon was not new and was locally known as “aokar”, he said, and similar seashells can be seen along several coastal areas, including Ibrahim Hyderi and other beaches in Karachi. “We have been witnessing this phenomenon for decades, particularly during June and July,” he said, explaining that water from the deeper parts of the sea rises to the surface and eventually pushes the seashells toward the shore, where they are dep