Ballast water bringing invasive species to Indian coasts: Scientists

Scientists fear that ballast water carried by ships is providing a vehicle to bring in exotic invasive species across the Indian Coast.
In this regard, a survey was conducted by the Department of Aquatic Biology and Fisheries, University of Kerala.
In the survey the presence of as many as 10 invasive species was found in the biodiversity-rich intertidal habitats of the Kerala coast. Some of invasive species include one species each of seaweed, bryozoan, mollusc and seven species of ascidian. The distribution of invasive species from the Kerala coast is likely assisted by shipping.
What is Ballast?

  • Ballast is a compartment in a ship that provides it stability as it holds water which moves in and out of it to balance the ship.
  • The compartment usually remains below the water level in order to counteract the weight above the water level.


  • Ballast is one of the biggest transporter of non-native (exotic/invasive) marine species.
  • Over 10,000 non-native marine species are transported across the world in the ballast water.
  • The colossal loads of ballast water carried by ships mainly transports fish, viruses, algae, , zooplankton, bacteria and benthonic invertebrates to harbours at a faster pace.
  • Expansion of ports and minor ports could pave for the introduction of alien species in Indian marine and coastal areas.



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