Manta rays (Manta birostris and Manta alfredi) are the largest rays in the world. Reaching a disc width of seven meters for M. birostris (the average height of a two-story house) and five meters for M. alfredi, these rays are one of the few large marine animals that are safe for divers to interact with. They are a major draw for the thriving eco-tourism industry around the world. Both M.birostris and M.alfredi are listed as globally Vulnerable on the IUCN Red List. Scientists only recently discovered that M. alfredi is a second separate species, so its biology and population status is poorly understood. Mantas are under threat from fisheries around the world, often caught for their meat, fins, liver, and branchial filaments. Mantas are particularly susceptible to threats because they live long, mature late in life, and have low reproduction rates.
Mantas eat by “filter-feeding” on zooplankton. As such, they are likely to be one of the first vertebrates globally to be directly impacted by changes in ocean currents that may result from climate change. Why? The currents affect the population of the zooplankton, its main food source. For example, a warming ocean would alter the abundance and distribution of zooplankton—which could impact the manta ray’s feeding habits and overall behavior. Changes in manta ray behavior will impact eco-tourism industries that rely on the predictable occurrence of these animals within this region.