First Survey on Sea Turtles' Interactions in Mussel Farms in Italy

Area of Science:

• Marine Biology
• Aquaculture
• Conservation Science

Background:

• Sea turtle interactions with mussel farms are a growing concern, particularly loggerhead turtles (Caretta caretta).
• Significant damage to aquaculture operations is reported, yet comprehensive national data are lacking.
• Mediterranean mussel (Mytilus galloprovincialis) farming is widespread in affected areas.

Purpose of the Study:

• To quantify sea turtle disturbance in Italian mussel farming.
• To analyze the dietary habits of loggerhead sea turtles concerning Mediterranean mussels.
• To assess the impact of these interactions on shellfish aquaculture.

Main Methods:

• Nationwide survey of Italian mussel farmers regarding turtle sightings and interactions.
• Analysis of gastrointestinal contents from stranded sea turtles along Adriatic and Tyrrhenian coasts.
• Correlation of turtle sightings with geographical location and seasonal water temperatures.

Main Results:

• Frequent loggerhead turtle sightings reported in northern Adriatic (summer) and southern regions (autumn).
• Mediterranean mussels identified as the most common mollusk ingested by sea turtles in the Adriatic.
• A notable increase in mussel ingestion by turtles was observed from 2018 to 2021.

Conclusions:

• Mussels are an increasingly consistent dietary component for sea turtles, indicating adaptive feeding behavior.
• Sea turtle interactions present significant management challenges for mussel aquaculture.
• A broader assessment of sea turtle impacts on Mediterranean shellfish aquaculture is recommended.