But Surasak, who has been in this post for only nine months, has much larger and more pressing illegal substances to contend with on his waterways, such as yaba (crystal meth), cannabis and rosewood. On his iPad, he runs through images of previous raids, in which naval officers pose in front of their "bounty", then outlines a map to highlight the dog smugglers' route. "There are two major strategic crossings," he says. "The dogs are collected from village households, or stolen, sold for 200 baht [£4] each, then sent to Tha Rae. From there, the bigger dogs are sent to a northern district, Baan Pheng, to go to China, while the smaller ones go to Vietnam. Five minutes across the river and the price of the dogs can go up 10 times. That's why the incentive is so high.