Development of the BioSentinel Health Index: A Proposed Framework to Support Sustainable Management of Marinas

Marinas support a range of recreational and commercial activities, but their enclosed hydrodynamics, and associated operations can generate diverse and rapidly changing environmental pressures. Conventional monitoring may miss short-lived events, previously unrecognized contaminants and the combined biological effects of multiple stressors. Valvometry, the measurement of bivalve shell behaviour, is an emerging biomonitoring technology that can provide continuous, integrated evidence of environmental variability and stress. This study developed and demonstrated the BioSentinel Health Index, a biologically informed framework combining bivalve-behaviour with assessments of data quality and management and response capability. Minute-scale valve-gape data from the mussel Mytilus galloprovincialis at Mandurah Ocean Marina, Western Australia, were used to derive ecosystem-health metrics. Mussels were classified as open for 87.9% of valid observations and exhibited broadly consistent rhythmic structure (spectral consistency score = 75.9%). Coordinated valve-closure events served as operational alarm indicators linked to a documented investigation and response pathway. At least three active mussels provided valid observations for 86.2% of the period. The single-station deployment only received partial spatial-coverage credit because it did not account for potential environmental variation across the marina. Under the proposed framework, Mandurah Ocean Marina received a preliminary score of 85.2%, placing it within the highest overall rating category.