A species is classified as endangered when there are fewer than 2,500 mature individuals or when the population declines by at least 20% within 5 years or two generations.
Currently, 7,079 species are classified as critically endangered, thus facing an extremely high risk of extinction in the wild.
The current state of crisis for many of these species is mostly because of human impacts on the ecosystem; we are responsible for the survival of these species and this blog argues that we have an ethical imperative to intervene to help them.
An example of a species that is endangered mostly because of direct human impact, combined with the problems of global warming, is the Hawksbill Turtle (Eretmochelys imbricata). This turtle species is known in particular for its beauty. Hawksbill turtles have a heart-shaped carapace, a tapered head that ends in a sharp point resembling a bird’s beak (hence its name), and a pair of claws adorning each flipper.
Image Credits: [Left image from https://www.fisheries.noaa.gov/species/hawksbill-turtle] [Right image from https://www.earth.com/news/endangered-turtle-poached-jewelry/]
These migratory reptiles help maintain a healthy coral reef ecosystem in the tropical waters of the Atlantic, Pacific and Indian oceans as they remove prey, like sponges, from reefs’ surfaces to provide better access for reef fish to feed. They are mainly found near coastlines with an abundant supply of sponges and sandy nesting sites within reach.
Why are they endangered?
Turtle shells have been prized amongst humans since ancient Egyptian times because of their stunning beauty. The International Union for Conservation of Nature estimates that millions of hawksbills have been killed within the last hundred years for the shell trade, although it became illegal in 1993. Also, Hawksbill eggs are still eaten around the world despite the turtle’s current protected status.
Habitat loss is another serious threat: coastal development has reduced the space for nesting, while global warming has been weakening coral skeletons through ocean acidification because of excess carbon dioxide in the atmosphere dissolving in the oceans, thus killing the coral reefs that Hawksbill turtles rely on for food. In addition, turtles have been dying because of increasing water pollution caused by plastic disposal into the ocean. In fact, turtles often ingest plastic as they mistake it for jellyfish or they get entangled in abandoned fishing nets, which can easily kill them through drowning or preventing them from escaping predators.
Image Credits: [Left image from https://sites.psu.edu/sracivic/2016/04/08/hawksbill-sea-turtle/] [Right image from http://www.bonaireturtles.org/wp/explore/why-are-sea-turtles-endangered/]
In response to the population decline, Hawksbill turtles are currently protected by international agreements like the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Convention on Migratory Species (CMS). While the CITES regulates or bans international trade of species under threat, the CMS provides a global platform for the conservation and sustainable use of terrestrial, aquatic and avian migratory animals and their habitats. Through these agreements, over the past 30 years, the population has slightly increased from 15,000 to approximately 25,000 individuals, but this improvement was not significant in comparison to the decline from 48,000 to 15,000 individuals that happened between 1960 and 1990.
What could we do to help?
Although shell trade has decreased significantly, we should avoid turtle-based cuisine. We can also contribute to a population recovery by reducing ocean pollution and contributing to controlling global warming. This is already being done through recycling and avoiding the use of vehicles or machines that emit greenhouse gases, such as carbon dioxide. Yet, it would be optimum to also avoid using pesticides and herbicides, and to avoid disposing of chemicals, cleaning agents and grease down the toilet, since these substances can dissolve in the ocean, affecting algae growth. This, in turn, negatively impacts the ecosystem, as they act as toxins for the aquatic species of the ecosystem.
These small and easily achievable changes may decrease water pollution if done by many, thus improving the environment of the Hawksbill turtles and other aquatic species.