Thousands of dead fish killed by industrial waste in Karachi

Around 35 tonnes of fish have been killed by toxins, originating from industrial waste, that have flowed into the sea via the Lyari River in Karachi, Pakistan. Hundreds of thousands of dead fish, from a variety of species, have washed ashore at Karachi, possibly due to polluted rainwater throughout the monsoon season flowing into the area's main river system.  

It is possible that the fish have been affected by contaminated rainwater that has flowed through the Sindh Industrial Trading Estate (SITE), eventually finding its way into the Lyari River. The fish were found floating in the backwaters of the Karachi Harbour, ranging in size from a few inches to one-and-a-half feet.

Fully-grown green turtles - an endangered species - have also been found washed ashore. According to the Karachi Fish Harbour Authority (KFHA), industrial waste causes contamination that results in the mass death of marine life at least twice a year in the area.   

KRHA has performed an investigation into the incident, which found that dissolved oxygen in seawater is the likely cause of the mass death of the different forms of marine life. The dissolved oxygen is introduced into the water by solid and industrial waste as well as mud and turbid water, according to the report.

The investigation also noted that no wounds were found on the fish and that there were no traces of oil on any of them, suggesting that the only cause of death was the large quantities of toxic waste that finds its way into the sea via local waterways.

The high levels of pollution flowing into the Lyari River and Malir River have created areas in the Karachi Fish Harbour and the Gizri Creek in which no marine or plant life can exist. Both waterways are affected by contaminants originating from industrial waste, which ultimately affect animal life throughout Karachi.

This is a problem that the area of Karachi face at several points every year, particularly when there is heavy rainfall. The amount of dead marine life in the harbour could ultimately affect the numbers of fish that are able to be caught by local fishermen, possibly causing economic problems on top of the pollution issues.