Ballast water and invasive species

•  A recent survey by the Department of Aquatic Biology and Fisheries, University of Kerala, had recorded the presence of as many as 10 invasive species in the biodiversity-rich intertidal habitats of the Kerala coast. They include one seaweed, one species of bryozoan, one species of mollusc and seven species of ascidian.
• It was assumed that the distribution of invasive species reported from the Kerala coast was likely to have been assisted by shipping. The survey argues that the expansion of ports in Kerala has opened ways for the introduction of alien species in marine and coastal areas.
• The survey also recorded the presence of a sea slug called Winged Thecacera ( Thecacera Pennigera ) in the southwest coast of India. Originally reported from the Atlantic coast of Europe, the presence of sea slug is currently reported from South Africa, West Africa, Pakistan, Japan, Brazil, eastern Australia and New Zealand.

What is Ballast?

• Commercial ships transport oil, iron ore, grain, and other cargo to ports worldwide. Most of these ships have large steel tanks, called ballast tanks, located along the sides and bottoms of their hulls. The ballast tanks contain seawater, or ballast water, which is pumped into or discharged from the ship during cargo transfer, usually in harbors and nearshore waters.
• When cargo is unloaded from a ship, the weight of the ship decreases, so seawater from the surrounding waters is pumped into the ballast tanks to compensate for the decreased weight. When cargo is loaded onto a ship, the weight of the ship increases, so ballast water from the ballast tanks is discharged into the surrounding waters to offset the increased weight of the cargo. Modern ships depend on this exchange of seawater to regulate the ship's stability and operate safely.
• The water pumped into a ship's ballast tanks may contain numerous aquatic organisms, including viruses, bacteria, algae, jellyfish, crabs, mollusks, and fish. If the organisms within a ship's ballast tanks survive the trip to the next destination, they may be released with the ballast water into waters in which they do not naturally occur. If these non native organisms survive and spread throughout their new environment, they may become invasive species. In this way, ballast water can accidentally introduce harmful microalgae and other organisms into the environment

Ballast Water Management Convention:

• The Ballast Water Management Convention, adopted in 2004, aims to prevent the spread of harmful aquatic organisms from one region to another, by establishing standards and procedures for the management and control of ships’ ballast water and sediments.
• Under the Convention, all ships in international traffic are required to manage their ballast water and sediments to a certain standard, according to a ship-specific ballast water management plan.
• All ships will also have to carry a ballast water record book and an international ballast water management certificate.
• The Convention will require all ships to implement a Ballast Water and Sediments Management Plan. All ships will have to carry a Ballast Water Record Book and will be required to carry out ballast water management procedures to a given standard. Existing ships will be required to do the same, but after a phase-in period.
• Parties to the Convention are given the option to take additional measures which are subject to criteria set out in the Convention and to IMO guidelines.
• India’s Union Cabinet has already approved accession to the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004 (Ballast Water Management Convention) of International Maritime Organization (IMO).

Analysis:

• Invasive species may be harmful to a new environment for several reasons. They can negatively affect human health and economic activities. Invasive species can decrease the abundance and diversity of native species and damage the ecological stability of native ecosystems. Invasive species are transported through ballast water and create environmental problems throughout the world
• Ballast water is one of the biggest transporters of non-native marine species. Studies done by experts have indicated that over 10,000 marine species are being transported across the world in ballast water carried by ocean-going vessels for stability and safety.
• Ballast water is also considered a vehicle for toxic algae causing red tides and harmful algal blooms.

By: Vishal