13 Nov Surveying Reef Health in the Banda Islands
From October 23 – November 3, CTC conducted reef health monitoring (RHM) and dive tourism carrying capacity surveys in the Ay-Rhun Islands MPA and Banda Islands. The dive team, including individuals from the CTC field team, TWP Laut Banda, and several students from the University of Banda Neira, conducted reef health monitoring at 15 sites and collected carrying capacity data at 11 monitoring sites that are also dive tourism destinations.
RHM was conducted using multiple methods, including the Point Intercept Transect (PIT) method, the Underwater Photo Transect (UPT) method, the Underwater Visual Census (UVC) for fish biomass and abundance, and a carrying capacity survey which measures the number of visits an area can support in a given time and includes both the Physical Carrying Capacity (PCC) as well as Real Carrying Capacity (RCC). The PIT method focuses on monitoring benthic reef conditions by examining conditions along transects at both depths (3 and 10 meters) to record the percentage of, among others, live hard coral, soft coral, algae, coralline algae, and other benthic categories. The UPT method also records benthic cover and creates a verifiable record via photographs taken at the same depth and transects as the PIT method. Data from the PIT and UPT methods can be compared to assess monitoring methods in terms of accuracy and consistency. The UVC method, meanwhile, records data concerning fish biomass and abundance for target fisheries and key species. Data on the carrying capacity of each dive site is needed to make diving regulations that ensure the sustainability of marine resources in the Banda Islands.
The results of the RHM indicate high numbers of juvenile fish, such as species of surgeonfish (Achanturus sp), unicornfish (Naso sp), fusilier species, and bluefin trevally (Caranx melampygus) as well as some species showing signs of spawning behaviors, such as peacock hind (Cephalopholis argus), humphead wrasse (Cheilinus undulatus), and surgeonfish species (Achanturus sp.). However, there were few fisheries target species present, especially larger or more mature fish belonging to fisheries target species. Charismatic species, including a scalloped hammerhead shark (Sphyrna lewini), a mangrove whipray (Himantura granulata), green and hawksbill turtles (Chelonia mydas, Eretmochelys imbricata) and three sperm whales (Physester macrocephalus) were observed during monitoring activities.
In addition, the RHM showed the coral reefs are generally healthy and in good condition, containing no mass coral bleaching and few instances of coral disease. The average Live Hard Cover Coral (LHCC) was 49.9 percent, a 4.9 percent reduction from the 2021 monitoring data LHCC of 54.8 percent. Eleven of fifteen RHM sites were assessed for dive tourism carrying capacity. Diving tourism activities were observed at Rhun, Ay, and Hatta Islands with dive boats originating either from liveaboard operators or dive operators based on Banda Neira.
CTC has supported the collection of coral health data since 2012. These data are used as one indicator to evaluate marine protected area (MPA) management effectiveness in the Banda Islands. Further, data from reef health monitoring is instrumental in supporting policy development and sustainable marine resource management.
Writers: Giselle Schmitz, Purwanto
Photos: Kasman/CTC, Tabitha Rudang/CTC