A concerted effort by Malaysia, Indonesia and Singapore to tackle piracy and robberies in nearby waters saw the number of incidents nosedive in the first six months of the year.

The countries pumped more resources into patrol activities, and one even zeroed in on prime suspects and issued them with stiff warnings.

Their activities cut the number of such incidents in the Strait of Singapore and Strait of Malacca to just one in the first six months .

This was after a spike last year, with the number hitting 104, up from 48 in 2014, according to the Regional Cooperation Agreement on Combating Piracy and Armed Robbery against Ships in Asia (ReCAAP) Information Sharing Centre.

The Malaysian and Indonesian authorities have improved their capabilities to address such incidents, noted Dr Collin Koh, a research fellow at the S. Rajaratnam School of International Studies' (RSIS) maritime security programme.

For instance, by October last year, the Royal Malaysian Navy had set up a Rapid Deployment Team to tackle crimes such as ship hijackings quickly, according to the Bernama news agency. The team consisted of two groups comprising 14 members and was equipped with two helicopters and a gunboat, an official was quoted as saying.

And in January this year, Tempo news reported that an Indonesian warship, KRI Imam Bonjol-838, had been deployed to increase Indonesia's naval patrol presence in the Strait of Malacca.

Category 1 incidents last year FEB 13: LAPIN At about 7.55pm, six to eight perpetrators armed with pistols and knives boarded the product tanker Lapin while it was anchored near Malaysia's Port Klang. They gathered the crew and took control of the tanker. Then, a vessel came alongside and siphoned five tonnes of diesel from the tanker. The perpetrators destroyed the ship's communication devices and stole ship and crew property. Before leaving the vessel, they tied the crew up and said an improvised explosive package was left on board and threatened the crew not to move. The crew managed to free themselves and sailed towards Thailand. The ReCAAP Focal Point (Thailand) boarded the ship at a location north of Ko Tarutao. It reported that a Thai Explosive Ordnance Disposal team disarmed the "improvised explosive package" and found only an electric circuit with no explosive or detonator attached. MAY 2: OCEAN ENERGY At around 9.30pm, eight perpetrators armed with guns boarded the vessel named Ocean Energy when it was close to Malaysia's Port Dickson on its way to Myanmar from Singapore. They ordered the crew to anchor the vessel and a barge came alongside it. The crew were locked away and 2,023 metric tonnes of fuel oil was discharged to the barge using a fuel hose and pump. After damaging the ship's communication equipment and taking the satellite phone and the crew's cash and cellphones, the perpetrators left the vessel at about 4.30am the next day. There were no injuries to the crew. AUG 8: JOAQUIM At about 2pm, an unknown number of perpetrators boarded the bunker tanker Joaquim when it was travelling to Langkawi, Malaysia, from Tanjung Pinang, Indonesia. Systems on the ship that provide information on its whereabouts to the authorities were reportedly turned off. About 3,000 metric tonnes of fuel oil was reportedly siphoned and power to the generator of the boat was reportedly cut off by the perpetrators. The crew were safe, except for the officer responsible for navigating the ship and bunker crew who were assaulted.

The Maritime and Port Authority of Singapore (MPA) and local enforcement agencies - the Police Coast Guard and Republic of Singapore Navy - also contributed.

They "worked with regional enforcement authorities in Malaysia and Indonesia to deter incidents through regular sharing of intelligence and stepped up patrols", said the MPA.

The three countries also stepped up efforts to detect unregistered ships around ports, and intensified checks on ships entering and leaving ports, and this has deterred some would-be offenders, said ReCAAP deputy director Nicholas Teo.

Most of last year's robberies occurred around a privately run anchorage in the Nipa area south-west of Singapore, said Mr Tim Wilkins, regional manager for the Asia-Pacific at the International Association of Independent Tanker Owners.

There, large ships carrying oil from the Middle East often transfer it to stationary smaller tankers, which then transport it around the region. Mr Wilkins said: "There are a lot of vessels at anchor and that makes them a relatively easy target and relatively close to certain smaller Indonesian islands, where theft and robberies can be launched."

Also, during the transfer of oil, the crew of such ships are often focused on the activity and find it harder to set aside manpower to keep watch, he added.

Stern warnings to suspects in Indonesian islands were also a major factor for the improvement, noted Dr Sam Bateman, an adviser to RSIS' maritime security programme.

The majority of the cases last year took place in Indonesian waters, he said. The attacks were carried out mainly by a few gangs from villages in Pulau Karimun Besar, Pulau Batam and other Indonesian islands close to the south of the straits.

They strike when ships pass close to their islands, Dr Bateman said. In response, police tracked down the suspects with help from the villages and issued stern warnings to them. They were told to stop illegal activities or they could face arrest, Dr Bateman said.

But Mr Wilkins noted that the number of incidents of theft and robbery in the Strait of Malacca and Strait of Singapore may not be as low as reported. Some ship operators may not report crimes as it could take a day or two for investigations, potentially costing them and their customers revenue, he said.