Evaluating ocean health and restoration success: A comprehensive study of the benthic quality index in the Bilbao estuary

Abstract

Ocean health is a global concern, and effective protection and restoration of estuaries require robust ecological information and appropriate metrics for comprehensive assessments. This study used 16 years of hard-bottom macroinvertebrate data from the formerly polluted Bilbao estuary to calculate the Benthic Quality Index (BQI). The BQI, based on species sensitivity values derived from richness-disturbance associations, was a valuable tool for evaluating the health of the macroinvertebrate community. Our findings demonstrated the responsiveness of the BQI to both natural and anthropogenic stressors, making it a useful indicator for assessing overall community health. Significant increases in BQI values, averaging 47%, were observed in the central section of the estuary, indicating successful restoration efforts. Furthermore, the BQI values showed a positive correlation with distance from the river mouth, reflecting a gradient of improved health. Notably, the BQI reliance on data rather than species-specific knowledge makes it suitable for assessing benthic community health across large temporal and spatial scales, where ecological information may be limited. In conclusion, the BQI provides a standardized measure of health that facilitates a better understanding of the state of our oceans. Its application in assessing estuarine health, as demonstrated in the Bilbao estuary, underscores its value in conservation and restoration efforts. By utilizing the BQI, we can make informed decisions to protect and restore estuarine ecosystems for the benefit of marine biodiversity and the health of our oceans.