An international piracy watchdog on Thursday hailed a drop in the number of piracy incidents worldwide in the first six months of the year, largely due to a decline in attacks in the troubled Gulf of Aden, according to dpa. A total of 196 incidents were recorded from January to June, down from 240 incidents in the same period last year, the International Maritime Bureau (IMB) said in a statement released by its Piracy Reporting Centre in Kuala Lumpur. In the first half of 2010, a total of 31 vessels were hijacked, 48 fired upon and 70 boarded in global waters. Guns were reportedly used in 100 incidents and knives in 35, while 597 crew were taken hostage, 16 injured and one killed by pirates, the London-based IMB said. The highest number of attacks - 51 incidents - was recorded in Somali waters. IMB director Pottengal Mukundan welcomed a drop in incidents in the Gulf of Aden, from 86 in 2009 to 33, still the second-highest number of incidents. "The actions of the navies in the Gulf of Aden have been instrumental in bringing down the attacks there," he said. However, Mukundan said increasingly bold Somali pirates were terrorising the Indian Ocean region as well as the Gulf of Aden, adding that an alarming 544 sailors had been taken hostage in those areas. The IMB report also noted an increase in the number of incidents occurring in Indonesian waters, which recorded 16 attacks in 2010 compared to three in 2009. The watchdog continued to urge seafarers to maintain their vigilance at sea, and for navies to increase patrol surveillance at piracy hotspots.