Scotland’s animal welfare charity has rescued 13 puppies from an illegal dealer at Cairnryan Port in Dumfries and Galloway.
The Scottish SPCA’s special investigations unit caught the individual, who had travelled from Belfast in Northern Ireland.
One puppy was so ill it had to be put down and another required emergency vet treatment for breathing problems.
The animal welfare charity said the puppies were in poor body condition and “filthy” when found, carrying diseases “consistent with being bred in horrendous circumstances”.
The rest are receiving urgent vet treatment and round-the-clock care at a Scottish SPCA animal rescue and rehoming centre.
Most are now said to be “lively and bright”.
Every year, thousands of pups are dying alone and in pain, at just days or weeks old, to fuel the tradeMike Flynn
Two Maltese terriers, four miniature Jack Russells and seven Jack Russell/cocker spaniel cross puppies were recovered.
The Scottish SPCA said the dealer transporting the dogs agreed to pay veterinary bills and was given a warning.
Since the Covid-19 lockdown, the port has been quiet but the charity believes puppy traders are beginning to move dogs again with the aim of selling them.
Chief superintendent Mike Flynn said while the lockdown lead to a dramatic decrease in the puppy trade, things are becoming more active again.
“We cannot stress this enough: the supply for badly-bred puppies will only disappear if public demand stops,” he said.
“Every year, thousands of pups are dying alone and in pain, at just days or weeks old, to fuel the trade.
“We will continue to fight the puppy trade every step of the way but we need each and every person to do their bit to help us stop it.”
He added: “Many responsible breeders put a hold on breeding during the pandemic but we are aware of some breeders ramping up prices due to lack of supply.
“This could drive people to buy a puppy without doing their homework on where they are getting it from.”
“There are thousands of adverts on [free listings] websites for puppies but there is no guarantee you are buying from a responsible breeder when you shop online.
“Many dealers will use false names and phone numbers to sell a dog, making it impossible for a buyer to get a hold of them when the pup falls ill.”