Abandoned, lost, or otherwise discarded fishing gear (ALDFG) poses a significant threat to Mediterranean coralligenous habitats. Such threat stems from the gear's presence on the seafloor and the mechanical harm it causes during its persistence and removal. This is particularly concerning given the slow growth rate of coralligenous species, which limits the habitat's capacity to recover from extensive damages. This work describes a standardized monitoring protocol to assess the ecological impact of ALDFG removal on coralligenous habitats, first applied within the Capo Carbonara Marine Protected Area (SE Sardinia, Italy). Seven sites affected by ALDFG were surveyed using a BACI (Before-After/Control-Impact) design at three time periods: before, immediately after, and one-year post-removal. Data collection followed the STAR protocol (STAndaRdized coralligenous evaluation procedure) to apply the COARSE index (Coralligenous Assessment by Reef Scape Estimate) for the evaluation of changes in ecological status in the three structural layers (i.e., basal, intermediate, upper) of the coralligenous habitat.

The results showed limited short-term impacts from ALDFG removal, with only two impact sites exhibiting a temporary decline in ecological status, followed by recovery after one year. Notably, the three layers of coralligenous habitat responded variably to the removal. The intermediate layer was the most affected, probably due to the loss of fast-growing species that colonized the ALDFG. The basal layer remained stable, while the upper layer exhibited localized declines in structural complexity with minimal recovery. Community composition analyses confirmed minor shifts attributable more to external environmental drivers than to the removal itself.

This protocol offers a replicable framework for evaluating the consequences of ALDFG removal and supports the importance of careful, site-specific assessments prior to intervention. When the removal is carried out by trained personnel, it is recommended to recover the integrity and the aesthetic value of the seafloor.