While positive environmental attitudes are commonly associated with environmentally responsible behaviour, this is not always the case. A new scientific paper jointly published by WWF Hong Kong, The University of Hong Kong (HKU), and The Education University of Hong Kong (EdUHK) in the Journal of Cleaner Production analysed the behaviour of people harvesting clams and found that while most clam-diggers have a high level of environmental awareness and self-reported behaviour, this may not reflect their actual behaviour, explained Dr Cheang Chi-chiu, Associate Professor at the Department of Science and Environmental Studies, EdUHK. This is the first in-depth study of the differences between perceived and actual behaviour of clam-diggers in Hong Kong. 

The Shui Hau sandflats on Lantau Island cover 30 hectares and include diverse ecological habitats high in biodiversity. However, this unprotected area currently faces severe human disturbance from unregulated clam-digging, which may lead to overharvesting, disturb the habitat and the creatures that live there, and have other related ecological consequences. 

The study assessed clam-harvesting pressure using a photographic survey of clam harvests, along with a self-reporting questionnaire to explore the behaviour of clam-diggers. The assessment found that they generally believe that their activities are environmentally friendly, as most of them have a positive environmental attitude and consider themselves to be environmentally responsible. Most prefer to keep only larger clams, but many have a poor understanding of the size of a mature clam, so many harvest those which are smaller than the recommended harvestable size. 

The fact that the reported perceived behaviour may not necessarily be environmentally friendly also indicates the insufficiency of using questionnaires alone to study environmental behaviour. It should, instead, be complemented with an independent assessment of how the clam-diggers behave. “Study of actual behaviour, in the fields of environmental and sustainability education, are relatively scarce. This clam-harvesting research has become a showcase study, providing empirical evidence to support the case that behavioural intention and real-life behaviour do not often align,” explained Dr Cheang.

To strengthen the protection of the ecologically important sandflat in Hong Kong, the researchers recommended (1) adding standard guidelines to the current management plan to regulate recreational clam-digging activities; (2) implementing a permit system limiting the clam-harvesting period to ease the current harvesting pressure and preserve the ecological value of Shui Hau; (3) using an independent assessment of clam-digging behaviour in addition to questionnaires; (4) adopting a comprehensive management plan, setting up core zones in the most ecologically sensitive areas, while allowing regulated recreational activities in less sensitive areas; and (5) designating a marine protected area in Shui Hau to preserve its ecological value.    

To learn more about the research, please click here.