Assessment of seawater quality : do public perceptions of seawater quality match indications given by macroalgae?

Abstract

Determination of seawater quality is an essential activity in coastal areas especially in ones that attract bathers. This study aims to investigate whether the Ecological Quality Status (EQS) of seawater in bathing areas in the Maltese Islands differs across sites. The study also aims to investigate the correlation between public perceptions and objective measures of seawater quality as well as factors affecting perception of seawater quality. Another objective of this study is to investigate the public's knowledge about macroalgae and opinion on macroalgae. The EQS of seawater in six coastal sites in the Maltese Islands is investigated using the EEI-c method of Orfanidis, Panayotidis and Ugland (2011) by assessing the presence and abundance of macroalgae. Stakeholder perceptions of environmental quality are assessed by polling the opinions of 198 questionnaire respondents in the same study sites. Statistical analysis is used to analyse the data from the questionnaires and the data from the macroalgal fieldworks. The results show that the EQS values differ across the study sites with St George's Bay scoring lowest and Dwejra scoring highest, with subjective scores given by stakeholders generally being higher than objective assessments based on macroalgal populations, even though there is a correlation between the two. Nitrate levels in seawater do not differ significantly across sites. Stakeholder opinions on seawater quality and on educational activities do not differ with age, gender, level of education, nationality, and bathing frequency. Conversely, seawater quality rating scores are affected by respondents' preference of bathing site and coastal area type (whether they preferred a rocky coast or a sandy beach). The study shows that using macroalgae for rapid assessment of environmental quality is an approach that can give reliable results in the Maltese Islands. Given that it has been calibrated with stakeholder perceptions and other indicators, this approach may be used to inform beach management strategies regarding seawater quality. The public's opinions may be used to inform educational initiatives to raise awareness of the importance of such habitats amongst other educational activities (since the majority of the respondents wish to see more educational activities on general environmental issues at the coastal areas).