There is a kind of theft that happens every day in a majority of the world’s poor countries – and in many of the richer ones too.
It usually happens out of sight, and most perpetrators get away with it.
The monetary value of this theft is about $15bn per year; the ecological cost can only be guessed at.
Yet many people would turn their noses up if they chanced upon a trove of this treasure.
Because these jewels are fish.
“Those that are fishing illegally, they are paying nothing, so we are losing something from our country”, says Mamadou Diallo, programme manager for the environmental group WWF’s West Africa office, and a former fisheries officer.
The amount that Africa is losing, if new figures from David Agnew of Imperial College London are right, is about $1bn per year – the cost of licences that illegal fishers should have paid to catch what they are catching.
The ecological cost may, in the long run, be much higher.
“The immediate ecological impact is damage to habitat, because they are using trawls, and trawls are not always good for the ecosystems – they damage habitat for fish,” says Dr Diallo.
“The second thing is pollution, because they are discharging at sea, and they can do anything they want.”
Precisely how much fish is removed illegally from West African waters is not known – apart from anything else, there is little good data on the state of stocks before the plunder began.
Elsewhere, where ecosystems and commercial fish numbers have been studied for longer, it is clear that illegal fishing can help wreak major damage.
In the Mediterranean Sea, where scientists estimate that illegal catches of bluefin tuna in recent years have almost matched legal catches in weight, changes are afoot.
“Some stocks are on the brink of collapse; but also, something remarkable has happened in the Mediterranean in the last couple of decades,” says Ricardo Aguilar, research director for the conservation group Oceana.
“Most of the vertebrates are over-exploited, so populations of invertebrates are growing – that’s one of the reasons why we have more jelllyfish.”
The Med, like the North Sea, has seen politicians repeatedly raise legal catch quotas well above the levels that scientists recommend – but it is equally clear that illegal fishing contributes to the decline in these stocks.
It is hardly likely to be otherwise elsewhere.
<Crossing the line<
Fishermen have a whole raft of dodges and evasions that fall on the wrong side of the law.
They may fish where they do not have a licence. Or they may have a licence, but flout its terms by going to forbidden areas, or fishing at the wrong time of year, or targeting prohibited species.
Another class of infraction concerns equipment. Some fishing methods are widely banned, notably driftnets, the subject of a 1992 UN prohibition on the high seas.
Many authorities regulate the size of mesh allowable in fishing nets; and many fishermen use a mesh size below that legal limit, in order to prevent the young ones escaping.
In the Mediterranean, using planes to spot swarms of tuna is banned; but evidence from several sources suggests the practice continues.
In some jurisdictions, regulations prohibit trans-shipment – transfer of catch from one vessel to another – because when a box of fish has been passed around between ships and perhaps re-labelled in the process, tracing its origin is next to impossible.
Which is precisely why some dodgy operations love trans-shipment.
And there is more. As well as illegal fishing, there is unreported and unregulated fishing – “unreported” when fleets do not report their catches to the appropriate national or trans-national authorities, and “unregulated” meaning operations that may just be legal, but which damage fish stocks and the wider marine ecosystem.