Understanding the behavioural gap between perceived and actual environmental behaviour: Investigating the clam-harvesting pattern in Hong Kong SAR, China

At every given site with conservation value, there is a dilemma between conservation and the use of natural resources. Here we describe the first in-depth investigation of the differences between perceived and actual behaviour in clam harvesting, with a view to determine a more sustainable approach to conserve a previously unprotected tourist and clam-harvesting site, Shui Hau, in Hong Kong. We assessed harvesting pressure by conducting a clam-harvest photographic survey and collected self-reported questionnaires in 2018. More than 90% of visitors per sampling day were assessed for the survey, resulting in 86 sets of completed questionnaires and clam harvest photographs, in which we counted the number of clams harvested and recorded the shell length of each clam. We found that the clam-diggers had high self-reported environmental attitudes and behaviour, and a higher new ecological paradigm score was associated with a better clam-digging related attitude and perceived clam-digging behaviour. The low correlation between self-reported behaviour and actual behaviour indicated that most clam-diggers had different concepts or definitions of the appropriate size of the clam harvest and the size of a mature clam, even though each digger reported that he/she had the highest level of environmental attitudes and behaviour. This differentiation may imply a transition problem between environmental attitudes and actual environmental behaviour. An effective management approach is needed to foster clam-diggers’ sense of biodiversity to embrace the long-term sustainable use of coastal resources.