Promoting the use of low-density fishing nets could enhance corals' chances of survival.

Coral reefs are crucial to marine ecosystems. However, as human activities intensify, abandoned fishing nets, a major form of marine debris, pose a significant threat to coral reef ecosystems. This study simulates the stress induced by abandoned fishing nets on corals in a coral nursery, examining how different net densities affect the growth, physiology, and microbial communities of Acropora hyacinthus and Acropora microphthalma. The results demonstrate that both coral species exhibit some adaptability under low-density fishing net stress. Additionally, A. microphthalma, which can grow upwards, appears more adaptable to fishing net stress across different densities. High-density fishing nets significantly hinder coral growth, primarily due to reduced energy availability caused by shading and intense competition between algae and corals. Moreover, high-density fishing net stress altered the microbial community structure of the corals. In A. hyacinthus, the dominant microbial group Endozicomonas decreased significantly under net stress, suggesting that high-density fishing net stress may disrupt the microbial community balance in corals. During recovery monitoring after the removal of fishing net stress, both coral species in the low-density group recovered more quickly in terms of physiological status and microbial communities. In contrast, A. hyacinthus in the high-density group recovered slowly, reflecting the lasting impact of high-density fishing net stress. This study highlights the multifaceted impact of abandoned fishing nets on coral growth, physiology, and microbial communities, providing preliminary insights for the development of future coral reef conservation and restoration strategies.