The Dr Fridtjof Nansen is plying the waves of the southern Indian Ocean, trawling for trash. Every time the ship's scientific crew threw down special nets, they hauled in pieces of plastics, underscoring the risk of dramatic upheavals in marine ecosystems even in one of the world's least-known and least-visited environments.

An estimated 5 trillion pieces of plastic currently float in the world's oceans, up from none in 1950 and posing a question about their potential impact on a food supply chain that stretches from plankton - which have been filmed eating plastic pellets - up through shellfish, salmon, tuna and eventually humans, not to mention whales.

A growing number of countries are ratifying an international agreement to combat illegal fishing, fueling interest in how best to implement the instrument. Illegal, unreported and unregulated (IUU) fishing is estimated to strip between $10 billion and $23 billion from the global economy, and their impacts undermine the way fish stocks are managed to make it a double concern around the world.

To help tackle the problem, FAO brokered the adoption in 2009 by its Member countries of the Agreement on Port State Measures to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing.

The agreement comes into force when 25 countries have deposited their instrument of ratification, known as acceptance of accession; so far, 12 countries have done so, the latest being Iceland in June. Two more states will soon join them.