The marine science department at Chulalongkorn University leverages longline transect methods to monitor pelagic and coastal ecosystems across the Gulf of Thailand. These standardized line transect surveys generate robust abundance and distribution data for species from seabirds to marine mammals.
By integrating ship-based visual surveys with GPS logging and GIS mapping, the department supports evidence-based policies for sustainable fisheries, protected areas, and ocean conservation in Thailand.
| Project Title | Region | Primary Objectives | Key Outputs |
|---|---|---|---|
| Gulf of Thailand Seabird Survey | Eastern Gulf, Thailand | Estimate density and distribution of seabirds | Annual density maps, species lists, methodology paper |
| Cetacean Monitoring Along the Andaman Coast | Andaman Sea, Thailand | Assess occurrence and relative abundance of cetaceans | Seasonal abundance indices, habitat use reports |
| Longline Transect for Pelagic Fish | Central Gulf of Thailand | Track trends in tuna and billfish groups | Length-based indices, bycatch analysis, management advice |
| Collaborative Marine Mammal Stranding Network | National coverage | Document strandings and live sightings | Database, emergency response protocol, training workshops |
Survey Design and Standard Protocols
Transect Layout and Stratification
The marine science department designs longline transect routes to balance spatial coverage and vessel safety. Stratification by depth, distance from shore, and historical encounter rates ensures representativeness across habitats.
Observer Training and Data Collection
Field teams follow strict protocols for timing, visibility, and angle correction. Training modules cover species identification, group size estimation, and noise minimization to reduce bias during surveys.
Data Analysis and Population Modeling
Distance Sampling and Density Estimation
Using specialized software, the team fits detection functions to perpendicular distance data. Density, abundance, and probability of detection are estimated with precision metrics for management reference.
Trend Analysis and Indicators
Time series from repeated surveys reveal population trends for key species. Indicators such as encounter rate per unit effort support early warnings and adaptive management.
Conservation and Policy Applications
Bycatch Reduction and Spatial Management
Results inform spatial closures, seasonal restrictions, and gear modifications. Recommendations align with national frameworks and regional agreements on marine biodiversity conservation.
Integration with Marine Spatial Planning
Maps of habitat use and relative abundance feed into coastal zone planning, offshore wind siting, and sustainable fisheries zoning. The department collaborates with government agencies to translate science into policy.
Operational Excellence and Future Directions
- Standardize protocols across vessels and seasons for consistent time series
- Integrate passive acoustic data to complement visual detections
- Expand collaboration with regional monitoring networks
- Develop open-access dashboards for managers and stakeholders
- Embed uncertainty quantification into all decision support products
FAQ
Reader questions
How are longline transects conducted safely in busy shipping lanes?
Survey protocols include time-of-day restrictions, lookout procedures, and communication plans with vessel traffic services to minimize conflict and ensure safety.
What species are most reliably detected during transect surveys?
Seabirds and larger cetaceans with consistent surfacing behavior are monitored with high reliability, while cryptic or deep-diving species may require supplementary methods.
Can these transect data inform bycatch mitigation strategies?
Yes, bycatch indices and species interaction maps derived from transects support the design of spatial closures and gear modifications to reduce unintended catch.
What training do field teams receive before going to sea?
Modules include species identification, distance sampling theory, safety at sea, and data logging standards to maintain consistency across surveys.