Roger Middleton: Stopping these attacks will be difficult - but the pirates may regret taking on America

Since the upsurge in attacks at the end of last year, more than a dozen countries have sent ships to the Gulf of Aden, patrols have thwarted several attacks, and the beginning of 2009 has been much quieter.

But the navies have fallen victim to their own success. The effectiveness of the patrols in the Gulf of Aden seem to have caused the pirates to refocus their attentions on the western Indian ocean.

One other factor lies behind the recent successes of the pirates: the weather. Very bad at the beginning of the year, it has now improved enough for pirates to get alongside targets with ease.

Now hijackers are threatening an area of up to two million square miles, they are much harder to locate. European, US and other navies are still overwhelmingly concentrated off Somalia's northern shore, hours or even days journey away from the recent attacks.

Although the pickings may be slimmer and the sea more dangerous in the ocean the pirates have found an easier place to work and the western Indian Ocean may soon be as notorious as the Gulf of Aden.

Attacks in the ocean mean ships going nowhere near the Gulf of Aden are under threat. Even the Seychelles is seeing ships seized in its waters, which could have a devastating impact on its tourism industry. Ships will need to maintain full speed and anti-piracy watches for much longer times and over greater distances, adding considerable costs.

The naval forces will have to find a way to extend some degree of protection over the Indian Ocean without compromising safety in the Gulf of Aden. The easiest way to do this might be to increase patrols by aircraft that can warn ships and even try to scare away pirates. But it will be very difficult, and perhaps impossible, to provide even the limited protection available in the Gulf across the millions of miles of sea now threatened.

Some say that the clause in UN Security Council resolution 1851 allowing militaries to pursue pirates into Somalia may now begin to be used. But this is unlikely to counter the massive financial motivations young men have to become pirates, and as Somalia lacks well defined pirate dens, it will be difficult to find targets.

America has been reminded that Somali piracy is not just a threat to its interests in the free movement of trade but that American citizens can also fall victim to these crimes. The moves against piracy were some of the last actions of the Bush presidency, and it is now likely that the new administration will intensify action against the pirates of Somalia. If so, those pirates who boarded the Alabama may not be the only ones to regret their daring.

Roger Middleton is the author of a major Chatham House report on piracy