Dr Anjani Ganase provides a review of recent scientific studies on manta rays, tropical forests, Antarctic sea ice and coral reefs.
Manta ray nursery off Florida
Monitoring of the giant oceanic manta ray (Mobula birostris) populations along the southeast coast of Florida has led scientists to believe that there is a manta ray nursery. Most of the mantas observed in the area were immature. This nursery would be one of three identified globally. The tracking of manta species over the years within this specific area reveal a high return to the area; some individuals were recorded multiple times over the four-year window.
Manta rays are relatively understudied yet the giant oceanic manta ray is endangered according to the IUCN (International Union for Conservation of Nature) red list. Genetic research also indicates the Western Atlantic rays may be a distinct species, referred to as the Caribbean Manta Ray (Mobula cf birostris). Research conducted in the area reveal a population of a lesser-known species of manta, the sickle fin devil ray (Mobula tarapacana), an olive-green variant occurring in the waters off the east coast of the US and Gulf of Mexico. This elusive species can be found in tropical water around the world, and yet little is known about their ecology. Mantas are long-lived species (45 years at least) with a slow reproductive cycle, rearing one pup every two to three years. The identification of their nursery grounds and protection of these habitats are critical to the conservation of the majestic creatures. Industrial and fishing activities overlap with the nursery and range of the mantas. Surveys carried out among the fisherfolk highlight that while that many fishers do support the protection of mantas, many struggled to identify manta species, and do not know techniques to safely remove fishing line and hooks from the manta. Engagement with the fishing community would boost the conservation effort.
Human exploitation and consumption study
A study done by the University of Victoria, Canada reveals that 31 per cent of all vertebrate species are exploited by humans. Exploitation broadly refers to any animal harvested from the wild for food, clothing, poisons, pharmaceuticals, pet trade, chemical manufacturing, fuels, fibres, jewellery, display, sport hunting and research. The research group used data collected on 47,000 species from the IUCN and revealed that up to 15,000 species were being exploited by humans. A comparison with other non-human predators shows that humans exploit as much as 300 times above the average number of species exploited by other animals for any given geographic area. The predator closest in numbers to humans with respect to the diversity of prey is the Eurasian-eagle owl (552). While 55 per cent of the vertebrates were exploited for food consumption, exploitation for the pet trade and for medicine were just as high. Fish (marine and freshwater species – 78 per cent) make up the largest proportion of consumed species, while birds, amphibians and reptiles were mostly ex
