Sea turtles are considered to be what is called a “keystone species”. The herbivorous green turtle and the sponge-eating hawksbill turtles are integral keystone species to any tropical marine ecosystem by performing critical ecological roles that are essential for the structure and function of these ecosystems.
For example, it has been suggested that the dramatic decline of these species in the Caribbean has radically reduced, and qualitatively changed, grazing and excavation of seagrasses, as well as depredation on marine sponges. This has in turn resulted in loss of production to adjacent ecosystems, such as coral reefs and disrupted entire food chains.
The leatherback turtle, which feed mainly on gelatinous prey such as jellyfish and salps, may consume the equivalent weight of an adult lion in jellyfish (440 lbs.) in a day. Recent studies show that jellyfish population’s blooms are more frequent and are continuously increasing in size and therefore have become problematic and are in fact a threat to the natural balance of marine ecosystems and towards human beings.
For this reason, the Leatherbacks play an essential role in controlling jellyfish population numbers and prevent the take over from a once fish populated ecosystem to a jellyfish abundant ecosystem in locations where fish stocks are already depleted.
References:
- Eckert, K. L., & Hemphill, A. H. (2005). Sea turtles as flagships for protection of the wider Caribbean region. Maritime Studies, 3(2), 4.
- Jackson, J. B. (1997). Reefs since columbus. Coral reefs, 16(1), S23-S32.
- Williams, J. (2015). Are jellyfish taking over the world. Journal of Aquactic and Marine Biology, 3, 00026.
- Wilson EG, Miller KL, Allison D, Magliocca M (2010) Why healthy oceans need sea turtles: the importance of sea turtles to marine ecosystems. Oceana protecting the world’s oceans, p.9.
