# Assessment of Ecological Quality Status in Shellfish Farms in South Korea Using Multiple Benthic Indices

## TL;DR

This study evaluates the ecological health of shellfish farms in South Korea using multiple benthic indices to guide sustainable management.

## Contribution

The study compares five benthic indices and a composite index to determine the best approach for assessing ecological quality in shellfish farms.

## Key findings

- The multivariate AMBI (M-AMBI) showed the best overall performance in assessing ecological quality status (EcoQs).
- Significant differences in macrobenthic community structure and EcoQs were observed between November and December in Gangjin Bay.
- Using multiple benthic indices and a composite index is recommended for a comprehensive assessment of EcoQs in aquaculture farms.

## Abstract

Using benthic indices to assess shellfish farms’ ecological quality status (EcoQs) can provide valuable scientific support for their environmental monitoring, impact assessment, and sustainable management. In this study, we applied five benthic indices (AZTI’s marine biotic index, BENTIX, benthic opportunistic polychaeta amphipoda index, benthic pollution index, and multivariate AMBI) and one composite index to assess EcoQs of shellfish farms in Gangjin Bay, South Korea. Results revealed apparent monthly variations in EcoQs, with the multivariate AMBI (M-AMBI) showing the best overall performance among indices. However, considering the ecological complexity and spatial variability of shellfish farm environments, the use of all five benthic indices and the composite index is recommended to comprehensively and accurately assess EcoQs in aquaculture farms.

South Korea is one of the world’s major centers for marine shellfish aquaculture. Since the industry’s rapid expansion began in the 1980s, concerns have grown regarding its environmental impacts on coastal marine ecosystems. Evaluating the benthic ecological quality status (EcoQs) of shellfish farms using benthic indices provides a scientific foundation for the sustainable management of aquaculture areas. In our study, five benthic indices (AZTI’s marine biotic index, BENTIX, benthic opportunistic polychaeta amphipoda index, benthic pollution index, and multivariate AMBI) and one composite index were selected to assess EcoQs of shellfish farms in Gangjin Bay, South Korea. Our results revealed significant differences in macrobenthic community structure and EcoQs between November and December in Gangjin Bay. Spearman correlation analysis and principal coordinates analysis (PCoA) demonstrated that the multivariate AMBI (M-AMBI) exhibited the best overall performance among indices. However, considering the ecological complexity, variability in farming practices, and site-specific conditions typical of shellfish aquaculture environments, the use of five benthic indices and a composite index is recommended to ensure a more comprehensive and robust evaluation of EcoQs in Korean shellfish farms.