![]() They also offer protection from predators like big sharks. Lagoons provide calm water suitable for the baby rays that are just starting to swim. It is also important to maintain the conservation efforts to minimise threats, allowing manta ray populations to survive and thrive.For newborn manta rays, using shallow sheltered habitats like lagoons as a nursery is crucial to ensure their survival. Given massive efforts to monitor the vast and remote areas of Raja Ampat archipelago, continued monitoring efforts and contributions from citizen scientists for the growing manta sighting database are required. In the sanctuary, the vast development of manta tourism have pushed down fisheries-related threats to manta rays to minimal.įinally, favourable environmental conditions affected by the El Niño events have helped manta rays continue to thrive. All of these have minimised shark fishing and the resulting potential of manta rays unintentionally being caught.įurthermore, the designation of Southeast Asia’s first shark and ray sanctuary in 2012 has given significantly stronger protection to manta rays. The use of fishing gear like gillnets and longlines has been restricted throughout Raja Ampat waters. The creation of a network of nine marine protected areas actively patrolled by local communities and authorities have forced sharks fishers to relocate to areas outside Raja Ampat, or change their livelihood. The series of conservation and management efforts implemented since 2007 by the Raja Ampat government has successfully minimised fisheries-related threats to manta ray populations. This research shows that it is not impossible to conserve large and highly migratory species such as reef manta rays. They stay there for a few years – which could increase their chance of survival – before they are large enough to join adult populations, like those in the study areas. Following this period, many of the expected baby manta rays likely live in sheltered nursery areas like Wayag lagoon or Fam Islands, both situated in Raja Ampat. (Author provided)ĭuring and shortly after the El Niño events, we observed high number of pregnant rays in the populations. These then increased opportunities for manta rays to feed in large feeding groups, enabling the manta rays to store much energy for reproduction and for mating.Ī reef manta ray with its mouth wide open and unfurled cephalic lobes to gorge as much zooplankton as possible. We also found that El Niño events generated more intense upwellings (upward motion of seawater) – bringing cold and nutrient-rich water to the surface. These sites, where manta rays frequently visit and gather for feeding and to be cleaned of parasites by cleaner fish, are important for their survival and health. Almost all known feeding and cleaning sites are located within the 2 million hectare marine protected area network. The thriving populations of reef manta rays strongly suggest this species is well protected in Raja Ampat waters. These resulted in the increase in manta ray populations in both marine protected areas. Furthermore, the populations typically saw a 20% boost from new individuals annually, which can be from newborns and/or larger rays from outside study areas. Each year, up to 93% of individuals in the populations survived. ![]() The manta rays were estimated to have high survival rates. In the 1990s and early 2000s, sharks were heavily caught in Raja Ampat using large gillnets and longlines, not to mention other illegal and destructive fishing practices by outsiders.Ī network of nine marine protected areas in Raja Ampat (Indonesia), including Dampier Strait and South East Misool. In Raja Ampat, there were anecdotal reports from the local community suggesting that reef manta rays were often caught unintentionally by non-local shark fishers. Some of these include East Nusa Tenggara and North Sulawesi (Indonesia), the Philippines, Papua New Guinea and Mozambique in Africa. ![]() Their populations have been depleted due to overfishing in many regions in Indo-Pacific. A female gives birth to only one pup every 2 to 6 years after about one year of pregnancy. Males start to sexually mature at 9 to 13 years old, while females require 13 to 17 years to mature. This species is characterised by late maturation and extremely low fertility, which make their populations especially vulnerable. They are not mammals, but cartilaginous fish that are related to sharks. Raja Ampat archipelago in West Papua is home to Indonesia’s largest population of reef manta rays, Mobula alfredi.
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