It should be stated at once that there is no established industry in sponge-fishing in Malaya... local sponges were occasionally fished and cleaned by the Malays for toilet use by the Asiatic population generally. It is noteworthy that cleaned and bleached Malay sponges, cut into small pieces and packed in cellophane, can be seen exposed for sale in a number of Chinese shops in Singapore, and retail sales appear to be increasing. Local sponges are obtained from the coral reefs and islands adjacent to Singapore, such as Sudong, Rhio and Ubin, and from the more distant Dutch islands.
The winning of sponges from the sea and their preliminary cleaning is almost entirely in the hands of Malays from the islands who have always shown skill as fishermen and seamen. But it is perhaps significant that there is no specific word in Malay for sponge, the term 'gabus' being used also for a cork or stopper. On the other hand the collection, sorting, trimming and marketing in Singapore – still the entrepôt of so many tropical products – is exclusively in the hands of the Chinese. Malayan sponges are usually found on coral flats in water which is about one foot deep at low tide. The Malays believe that a depth of one to six feet is the most favourable for the growth of sponges. At Pulau Sudong the Malays go as far as to state that at depths greater than two fathoms sponges cannot be located.
In Malaya the method of collection being by hand, the Malay is able to take a catch of sponge from the reef only at favourable low tides, which may occur two to four times a month. The system of wading in to the sea up to the neck is not practised in the Malay Archipelago. The opacity of the water, the existence of strong currents, the confused and uneven bottom, and the possible presence of sharks render this method impracticable. Even with the beds uncovered as at low tide it requires not a little experience to be able to recognise a true sponge in amongst the varied flora of the coral reef. In its natural habitat the sponge appears black, is of the consistency of tough beef liver, and exudes a characteristic but not unpleasant odour.
– Stanley G. Willimott, 'Malayan Sponges'. Journal of the Malayan Branch of the Royal Asiatic Society, October 1939.