Achatina Snail: An invasive species in Hong Kong 1. History

The first animals I saw on arriving in Hong Kong on a dark November night in 1965 were giant snails, Achatina or Lissachatina fulica. They were in the dank area around the entrance to the block of flats in what was then called the University Compound. Even after twenty hours (including refuelling stops at Athens, Tehran and Delhi) on a Qantas Boeing 707 and the first sight of Hong Hong harbour from the vehicular ferry, the snails registered. They were big.

by Alexander C Jenner (Wikimedia Commons)

I soon discovered that these East African snails had spread widely in the tropics and were a considerable pest to farmers and gardeners. They were first noticed in Hong Kong in 1941 shortly before the Japanese Invasion in December. Since adults were found it was estimated that introduction occurred around 1937. Laying thousands of eggs over a lifespan of 10 years it is not surprising that its population and range increased rapidly.

The photograph in Jarrett's article
Hong Kong Naturalist vol. 2, 1931

They were first noticed by Vincent Hubert Charles Jarrett (1895-1973), a journalist on the South China Morning Post who was also a naturalist. At the time of the Japanese invasion he was Assistant Editor. Gwulo has a photograph of Jarrett in the 1941 here. He wrote numerous articles, including nature notes, for the newspaper and also for the Hong Kong Naturalist. He described the spread  of Achatina through Malaya and Singapore (he was born in Malacca) where it seems to have been introduced as a food for ducks. He also noted that it had been found in China by Herklots while on a visit to Amoy (now Xiamen) in 1931. Before the snail’s arrival in Hong Kong he raised a vital question:

Latest information from Malaya is that the snails are now found in increasing numbers everywhere, and even wander over the golf courses, where the chagrin of a player whose ball is stopped by a giant mollusc in the grass may be imagined. It is not known whether the question has yet arisen about counting Achatina fulica a natural or artificial hazard. It may be hoped, as a conclusion to this note, that the question will never have to be debated on one of this Colony's courses!

After release from internment at Stanley, Jarrett travelled to Britain in October 1945. I do not know whether or not he returned to Hong Kong. In 1959 he was appointed OBE for his services as ‘Editor of Press Summary’ at the British Embassy in Oslo. He died in Norway in 1973.

Geoffrey Herklots, who remained in Hong Kong as a member of the government after internment, brought Hong Kong up to date with the Achatina pest in an article for the South China Morning Post on 22 May 1946. He reported the snail was now well established on Hong Kong Island. He proceeded to give advice on how it could be killed by gardeners. With characteristic energy he held snail hunts:

On May 19, 126 snails weighing 6-lbs. were collected at Sookunpo; on May 18 and 19 330 snails weighing 20-lbs. at the Protestant Cemetery, and on May 18, 94 weighing 4-lbs. at Government House.

He ended:

These snails are edible. There is a pile of hundreds of empty snail shells at Government House. The obvious inference is that the former Japanese Governor or his staff, regarded them as a delicacy…

It is now known that Achatina snails carry a whole host of human parasites. There will be survivors of the Japanese occupation and their families hoping that a few of the more nasty ones attached themselves to the intestinal walls of the then occupiers of Government House.