Estimating spatial patchiness of a threatened marine snail based on movement behavior

Area of Science:

• Marine Ecology
• Conservation Biology
• Movement Ecology

Background:

• Spatial patchiness in animal distributions is often overlooked in management, which typically relies on mean population densities.
• Species like queen conch (Aliger gigas) that form dense aggregations are vulnerable to overexploitation due to their predictable locations.

Purpose of the Study:

• To investigate the drivers of spatial heterogeneity in queen conch distribution using biologgers.
• To quantify conch movement behavior, activity rates, environmental influences, and dispersal patterns.
• To model conch dispersal in breeding areas to inform management strategies.

Main Methods:

• Biologgers were used to track queen conch movement and quantify behavior.
• Distance to next encounter analyses were performed to measure spatial separation between conch patches.
• Field survey data were integrated with dispersal estimates to calculate patch characteristics and population densities.

Main Results:

• Most queen conch were found in aggregations (patches with multiple individuals).
• Areas with fishing pressure showed a lack of conch and aggregations, indicating mean density is a poor management indicator.
• Observed aggregation sizes and densities were consistent, with breeding aggregations rarely exceeding 330m in length.

Conclusions:

• Movement ecology provides a valuable alternative context for managing patchily distributed species.
• Small-scale spatial management interventions are feasible for protecting queen conch aggregations.
• Understanding species-specific aggregation needs is vital for effective conservation of spatially structured populations.