Ghost fishing impacts on hydrocorals and associated reef fish assemblages

Area of Science:

• Marine Biology
• Ecology
• Conservation Science

Background:

• Ghost fishing, caused by lost or discarded fishing gear, poses a significant threat to marine ecosystems.
• Branching corals, like Millepora alcicornis, are particularly vulnerable to entanglement, impacting reef structure and associated species.
• Coral reefs provide critical habitats for fish, making their structural integrity vital for associated fish populations.

Purpose of the Study:

• To investigate the impact of entangled fishing lines on Millepora alcicornis colonies.
• To assess changes in fish abundance, richness, and behavior associated with entangled corals.
• To understand the broader ecological consequences of ghost fishing on tropical shallow reef ecosystems.

Main Methods:

• Field study quantifying Millepora alcicornis colony volume and mortality.
• Video analysis to determine fish abundance, richness, and behavior.
• Observation of feeding attempts in herbivorous fish species.

Main Results:

• Coral mortality significantly increased with the amount of entangled fishing lines.
• No significant changes were observed in the abundance and richness of fish assemblages.
• A notable decrease in feeding attempts by two herbivorous fish species was recorded.

Conclusions:

• Ghost fishing directly damages branching corals and disrupts crucial coral-fish interactions.
• Impacts on herbivorous fish feeding behavior can affect algal dynamics and overall reef health.
• Effective management of coastal fisheries and monitoring are essential for maintaining tropical reef integrity.