The International Maritime Bureau's report for 2011 records a marginal decline in acts of piracy across the globe, the number of pirate attacks and armed robbery reported in 2011 being 439 against 445 in 2010.

“The falling numbers come after four consecutive years of increased piracy and armed robbery worldwide,” says the report, which recorded that 275 of the 439 attacks were carried out from the shores of Africa - Somalia in the east and the Gulf of Guinea on the west.

Eight crew members were killed during 2011, the same number as in the previous year, though the number of hostages held by pirates fell to 802 in 2011 from the four-year high of 1,181 in 2010.

Calendar year 2011 saw 45 vessels hijacked; 176 vessels boarded; 113 vessels fired upon, and 105 vessels coming close to being attacked.

One bright spot in the report is that the number of successful hijacking of vessels declined from 49 to 28 during 2011. Somali pirates accounted for 54 per cent of the incidents during 2011 and the overall figures for Somali pirates increased from 219 in 2010 to 237 in 2011.

The IMB report is a pointer to the success of international naval forces deployed against the pirates in the afflicted areas.

Had it not been for the pre-emptive strikes by some of the naval forces, the number of Somali pirate attacks would have been higher, the report said.

In the last three months of 2011, pre-emptive strikes resulted in the disruption of at least 20 pirate action groups before they became actual threats to cargo carriers.

The presence of the navies is the key reason why the last quarter of 2011 saw a drastic fall in piracy-related incidents.

These incidents dropped to 31 from 90 during the last three months of 2011 and 2010 respectively.

The number of vessels hijacked during the last quarter of 2011 fell to four from 19 in the last quarter of 2010.

The types of ships that came under attack during 2011 included 100 bulk carriers; 71 chemical tankers; 62 container ships; 61 tankers; 35 general cargo vessels; 32 tugs; 29 product vessels; and 11 fishing vessels.