![]() These encounters always reminded us how intelligent these animals truly are. ‘Our team members could spend entire dives cutting away at the nets and lines- the mantas patiently cooperating, remaining calm, barely swimming, the whole time. ‘There were times I would find myself hooked and entangled myself as I tried to rescue the mantas, and I constantly worried about getting pulled into the depths once connected to the mantas and the lines. ‘Some of the mantas were so badly entangled with heavily fouled nets that the lines would embed into their skin, making rescue extremely difficult and dangerous,’ added Dr Marshall. ‘Every year we would spend dive after dive removing fishing lines, hooks, and, worst case, large fishing nets from the mantas. ‘I was shocked to see how prevalent entanglements were in the region,’ said Dr Marshall. MMF co-founder and the world’s principal giant manta ray researcher, Dr Andrea Marshall, found herself having to regularly free entangled manta rays during her research dives. ![]() The 12 best places to dive with manta raysĭr Andrea Marshall freeing ain injured giant oceanic manta ray from heavy fishing lines (Photo: Andrea Marshall/MMF)Ī total of 563 animals were found to have injuries, 348 – one in eight of all the manta rays identified – were either entangled or ‘showed evidence of previous line scarring’.While it has been illegal to catch the rays in Ecuadorean waters since 2010, their presence and tendency to swim near the surface of the water for long stretches make them vulnerable to being caught by abandoned, lost or discarded fishing gear, accidental boat strikes and bycatch. Unfortunately, the same conditions which attract giant oceanic manta rays to the area also create perfect conditions for industrial-scale fishing. The population is driven to the region by the convergence of equatorial currents and strong upwellings which drive nutrient-rich water to the surface between June and September each year, providing sustenance for the krill and plankton which in turn become food sources for the filter-feeding manta rays. Identification of giant manta rays for the study was provided by photographs taken by scuba divers, guides and instructors, from as early as 2005 – before dedicated research expeditions to the region had begun – using the spot markings present on the mantas’ ventral side, which are unique to each animal. Marine Reserve off the coast of Ecuador Ecuador in 1996, and research has been focused on these areas since 2010. Seasonal, predictable aggregations of giant mantas were discovered at Isla de la Plata in the Machalilla National Park, and the Bajo Copé They are distributed circumglobally in tropical and temperate waters, but, unlike their near-shore resident cousins, the reef manta ray ( Mobula alfredi), giant mantas spend most of their time in the open ocean, congregating around sea mounts and oceanic islands, which makes them especially difficult to study. ![]() Giant – or oceanic – manta rays are the largest known species of ray, with a disc width (wingspan) that can measure up to 7m across, although the average disc width of an adult is approximately 4.5m. Data modelling estimates the overall size of the ‘super-population’ to be in excess of 22,000 oceanic manta rays – more than ten times the size of any other population so far known to science. The world’s largest population of giant oceanic manta rays ( Mobula birostris) has been formally identified off the coast of Ecuador, according to new collaborative research by the Marine Megafauna Foundation, Fundación Megafauna Marina del Ecuador, the Manta Trust and the Ocean Ecology Lab at Oregon State Univerity’s Marine Mammal Institute.Īccording to the study, recently published in the journal Marine Ecology Progress Series, more than 2,800 individual animals were identified between 2005-2018. MMF Co-founder Andrea Marshall with a friendly giant oceanic manta (Photo: Andrea Marshall/MMF) Revillagigedo Archipelago & Guadalupe Island. ![]()
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