The National Council of SPCAs (NSPCA) this week found a shipment of around 5 300 crabs at an OR Tambo International Airport cargo facility that had been forgotten about for nine days.
They had been left in the sun, were either dead or dying, infested with maggots and had gone without food and water, it said in a statement.
More than half of the crabs that were still alive had to be euthanised.
The crabs had arrived last Sunday from Mozambique and were meant to be sent to Hong Kong.
Due to the unrest there, the flight was cancelled and the crabs were forgotten about, it said.
According to the NSPCA, the company that sent the crabs had not adhered to International Air Transport Association Regulations, in that it packaged and restrained the crabs in an inhumane manner.
The cargo facility had also disregarded these regulations by leaving these creatures in the sun, it added.
"It is disheartening that these living creatures would be treated so horrifically and that the attitude towards crabs is that of 'perishable cargo' as opposed to live animals," said NSPCA Special Projects Unit manager Arno De Klerk.
The NSPCA was investigating the matter and said it would not hesitate to lay charges.
GET THE NEWS at your fingertips and download the News24 app for Android here now. Get it for your iPhone here.
KEEP UPDATED on the latest news by subscribing to our FREE newsletter.
- FOLLOW News24 on Twitter