Somali pirate attacks in the Arabian Sea and Persian Gulf are continuing to rise, but an increase in the use of armed guards is slashing success rates, according to an Aon Risk Solutions report.

The risk management division has released its first piracy update report to clarify the changing trends in this arena, giving shipowners data to better manage their exposure.

It shows that despite recording a 17% increase in the number of attacks in the Arabian Sea and Persian Gulf from 231 in 2009/10 to 278 in 2010/11, risk mitigation efforts have reduced the piracy success rate from 30% to 19%.

Aon says this has been the direct result of anti-piracy measures such as the use of armed guards, naval resources or “citadels”.

“No vessels [with armed guards on board] have been taken… and Aon has regularly endorsed the use of these measures as an alternative insurance policy,” the report says.

Although most piracy has been concentrated around East Africa, Aon warns that West Africa is now facing increased crime, including vessel seizures, crew kidnaps and robberies.