Simulating drifting fish aggregating device trajectories to identify potential interactions with endangered sea...

Area of Science:

• Marine Biology
• Fisheries Science
• Conservation Ecology

Background:

• Drifting fish aggregating devices (dFADs) are widely used in purse-seine fisheries in the Pacific Ocean, with 46,000-65,000 deployed annually.
• Concerns include entanglement of marine fauna, marine pollution, and habitat damage from dFADs stranding on sensitive ecosystems.

Purpose of the Study:

• To assess and quantify the connectivity between dFAD deployment zones and critical habitats of endangered leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles in the Pacific.
• To identify regions where dFADs may interact with sea turtle migration, feeding, and coastal habitats.

Main Methods:

• Conducted passive-drift Lagrangian experiments using simulated dFAD drift profiles.
• Compared simulated dFAD trajectories with known important sea turtle areas in the Pacific Ocean.

Main Results:

• Simulations indicated that up to 60% of dFADs deployed in equatorial regions can reach essential sea turtle habitats.
• Connectivity was lower when considering only current dFAD deployment areas.
• Identified specific regions in the southeastern Pacific, western Pacific (Indonesia, PNG, Solomon Islands), and equatorial Pacific (south of Hawaii) with potential dFAD-sea turtle interactions.

Conclusions:

• dFADs pose a significant risk of interaction with critical habitats of endangered sea turtles in the Pacific.
• Further research is essential to quantify sea turtle entanglements and the impact of new management strategies, such as biodegradable or non-entangling dFAD designs and adjusted deployment locations.