Impact of Ballast Water on Marine Ecosystems in India: Case Study on Charru Mussels

What’s in today’s article?

• Why in News?
• Invasive Species and Their Threat to Ecosystems
• What is Ballast water?
• Laws regulating movement of ballast water

Why in News?

The Tamil Nadu Water Resources Department (WRD) has informed the National Green Tribunal that it has requested ₹160 crore from Kamarajar Port in Ennore, Tamil Nadu, to address the removal of invasive charru mussels (Mytella strigata) along the coast. These mussels are harming marine ecosystems and obstructing fisher boat movements, impacting livelihoods.

The WRD accuses Kamarajar Port of contributing to the spread of the invasive species by failing to regulate ballast water from ships.

Invasive Species and Their Threat to Ecosystems

• About
  • Invasive species are non-native organisms that are introduced, either accidentally or intentionally, into a new environment where they do not naturally occur.
  • These species often spread rapidly and can cause significant harm to the local ecosystems, economies, and human health.
  • Invasive species can outcompete native species for resources, alter habitats, disrupt food webs, and even lead to the extinction of native species.
  • One of the primary ways invasive species are introduced is through human activities, such as global trade and transportation.
  • For example, ballast water from ships, which is used to stabilize vessels, often contains various marine organisms.
  • When this water is discharged in a new location, it can introduce invasive species to the area.
• Case Study: Charru Mussels (Mytella strigata)
  • About
    • The Charru mussel (Mytella strigata) is an example of an invasive species that has become a significant ecological threat.
    • Native to South America, the charru mussel has spread to other regions, including the coast near Kamarajar Port in Ennore, Tamil Nadu, India.
    • The spread of this species is largely attributed to ballast water discharge from ships, which is not adequately regulated.
  • Threats posed
    • The charru mussel poses a severe threat to marine ecosystems. It reproduces quickly and forms dense colonies, which can outcompete native species for space and resources.
    • The mussels attach to various surfaces, including rocks, other marine organisms, and even man-made structures like boats and docks.
    • This can lead to the displacement of native species, changes in habitat structure, and a reduction in biodiversity.
    • In the Ennore region, the proliferation of charru mussels has also had economic and social impacts.
    • The dense colonies of mussels hinder the movement of fishing boats, affecting the livelihoods of local fishermen.

What is Ballast water?

• Ships require a certain level of immersion in the sea for stability. To maintain this, when cargo is discharged and the ship rises in the water, sea water, known as ballast water, is taken into tanks onboard.
• Conversely, when cargo is loaded and the ship sinks lower in the water, the ballast water is pumped out.

Laws regulating movement of ballast water

• Background
  • Traditionally, there were no restrictions on the intake and discharge of ballast water at various locations, including ports and along coasts.
  • However, since ballast water can carry invasive species that harm ecosystems in other countries, the global shipping industry has moved to regulate ballast water discharge.
    • In India, scientists have recorded nearly 30 invasive species coming from ship ballast water.
    • Among the most harmful in recent times is the charru mussel, Mytella Rigata.
    • In the Pulicat lake in Tamil Nadu, as in Ashtamudi lake in Kerala, this mussel has replaced almost all other species.
    • Its survival rate and egg production is very high. Though of marine origin, it can survive even in fresh water.
• Global regulations
  • The Ballast Water Management (BWM) Convention, enforced by the International Maritime Organization (IMO) since 2017, aims to prevent the spread of harmful aquatic organisms and pathogens through ships' ballast water.
  • Ships must now manage their ballast water to remove or neutralize these organisms before discharge in new locations.
  • Newly built ships with ballast water management systems treat the water with chemicals to eliminate biological organisms.
    • Older ships without such systems are required to exchange ballast water taken in at ports with neutral ocean water during their journey.
  • Countries like Australia and New Zealand are particularly strict in enforcing these regulations to protect their marine ecosystems.
  • Australia, which frequently handles ballast water due to its role as a major raw material supplier, conducts rigorous checks on ships, especially near sensitive areas like the Great Barrier Reef, to prevent ecological damage.
• Situation in India
  • As of July 2024, 97 countries have signed the Ballast Water Management (BWM) Convention of the International Maritime Organization (IMO), but India is not among them.
  • Consequently, ships docking at Indian ports are not obligated to follow the BWM Convention.
  • While Indian ports enforce other rules, such as those related to oil discharge, ballast water remains unchecked.
• Way forward for India
  • Maritime law experts note that ports are facilitators and cannot be held liable unless a law is in place.
  • If there is any evidence that a vessel has pumped out the ballast water that led to the invasive species, then the vessel owner can be held liable if a law is in force.
  • Hence, India must join the BWM Convention to address this gap.

Q.1. What is Charru mussels (Mytella strigata)?

Charru mussels (Mytella strigata) are invasive species native to South America that have spread to other regions, including India, primarily through ballast water discharge from ships. These mussels form dense colonies, outcompeting native species, disrupting marine ecosystems, and hindering fishing activities, thereby posing significant ecological and economic threats.

Q.2. What is International Maritime Organization (IMO)?

The International Maritime Organization (IMO) is a specialized United Nations agency responsible for regulating shipping. It sets global standards for maritime safety, security, and environmental performance. Established in 1948, the IMO aims to ensure safe and efficient international shipping while protecting the marine environment through conventions and protocols.

Source: Does India have laws on the movement of ballast water?