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Spatial and Temporal Patterns in Marine Resource Use within Raja Ampat Region from Aerial Surveys

Wilson, J.; Rotinsulu, C.; Muljadi, A.; Wen, W.; Barmawi, M.; Mandagi, S.

The Raja Ampat archipelago is located off the northwestern tip of Indonesia’s West Papua Province in the ‘heart’ of the Coral Triangle and encompasses four million hectares of small islands, coral reefs and open waters. This region is home to the world’s most diverse coral reefs and populations of endangered sea turtles and marine mammals including dugongs.

In 2006, the Government of Raja Ampat established six new MPAs bringing the total number of MPAs to 7 and encompassing close to 1 million hectares. The population of Raja Ampat Regency in 2006 was 32,055 but is rapidly expanding. Most people rely on natural resources as a source of food and income. Understanding existing patterns of resource use, distribution of key habitats and species is critical to inform management decisions and spatial planning for natural resource management and MPA planning. Aerial surveys are a well established and useful method to collect data across large spatial scales and have been used to collect information on the distribution and abundance of marine mammals and other large marine biota.

In January and September 2006, aerial surveys were done in Raja Ampat using a small fixed wing aircraft. Each survey lasted for 30 hours over 5 days and covered approximately 4,000 km. Observers noted and described all vessels and their activities, recorded fixed gear or structures and any biota such as turtles or marine mammals. GPS locations and photos were recorded for all observations. Data were mapped and analyzed graphically to determine differences in resource use or distribution of biota among areas within Raja Ampat and among MPAs.

The majority (>75%) of vessels seen were small fishing boats – canoes with small or no engines. This demonstrates a high level of use of coastal marine resources by local communities for artisinal fisheries. Although small vessels are more numerous,other studies in the region have shown that up to 80% of fisheries catch is taken by a few outsiders using larger vessels.

Fixed gears in Raja Ampat are predominantly used for fishing and are unregulated. However a significant amount of fish are likely to be caught by these structures or using these structures as support for fishing activities in remote areas (Bailey et al. 2008). Understanding the number, location and type of fixed gears is important in understanding the true amount of fishing effort in Raja Ampat and can be used as a basis for any future licencing or quota system to regulate these fishing gears.
Manta rays, whales and dolphins was significantly more abundant in January with more than twice the number of individuals seen compared to September. Most biota sightings were between Sorong and Salawati Island, in Dampier Strait and around Kofiau Island. The MPA network currently does not encompass many of the important areas for these species.

This study has shown that aerial surveys are a highly useful method to survey resource use and large marine fauna in remote and extensive areas. There is great potential to combine aerial surveys with vessel activities to assist in enforcement patrols and alert authorities to illegal activities. It is also an excellent method to assess the number, type and distribution of unregulated structures such as fishing traps and shelters.