User:Oderdul/ Endangered sea turtles

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There are seven species of sea turtles that current live in the oceans around us. The seven species of sea turtles that still reside in our oceans are; the Green turtle (Chelonia mydas), the Loggerhead (Caretta caretta), the Flatback turtle (Natator depressus), the Hawskbill sea turtle (Eretmochelys imbricata), the Leatherback turtle (Dermochelys coriacea), the Olive ridley (Lepidochelys olivacea), and the Kemp's ridley sea turtle (Lepidochelys kempii). Despite being nearly universally beloved, 6 of the 7 sea turtle species are endangered. The Green turtle, the Hawksbill, the Kemp's ridley turtle, the Leatherback turtle, the Loggerhead turtle, and the Olive Ridley turtle are the six sea turtle species that are currently threatened and endangered. These species are now protected under the U.S. Endangered Species Act for recovering their depleted populations.

Threats

Many threats to sea turtles are anthropogenic- caused by human activity. Humans have always been one of the biggest threats to sea turtles through poaching and overexploiting, as well as inducing climate change and pollution.

Overharvesting

Coastal communities harvested turtle eggs for a protein source and other products for many generations, some areas still harvest them today. Sea turtles have also been recorded to be harvested for their meat, skin and shells. The harvesting largely increased over the 20th century as commercialization of sea turtle products increased- creating an issue in overharvesting the sea turtle populations to where sea turtles are now recognized by the World Conservation Union (IUCN) are "critically endangered."

Bycatch

Image of a loggerhead sea turtle caught in a ghost net- a fishing net that has been abandoned, lost or otherwise discarded in the ocean.

Bycatch refers to the incidental capture of non-target species during fishing operations. It is a global issue for management of marine resources, as it occurs in virtually all fishing fleets an can lead to many marine life population declines. It is estimated that around 250,000 Loggerhead and Leatherback turtles are killed every year due to being entangled in fishing gear. Sea turtle bycatch occurs from trawling, longline fishing, the use of gillnets, pound nets, dredges and to a lesser extent, pots and traps

Trawling is a method of fishing where a large fishing net is dragged behind one or more boats. When sea turtles get caught in these trawling nets, they are unable to surface to breathe and suffocate if they are underwater longer than 30 minutes. Loggerheads are caught in trawls in greater numbers than other species, but Kemp's Ridleys, Greens, Leatherbacks and Hawksbills are also captured.

Longline fishing nets is a long line of netting trailing behind a boat with baited hooks at certain intervals to attract desired fish. Sea turtles can become hooked onto the baited hooks and trapped to the net. Air breathing turtles can often still surface after they are snared, therefore most deaths are not caused by drowning but by "injury related to hooking or entangling.

A gillnet is a wall of netting that hangs in the water column, typically made of monofilament or multifilament nylon. Gillnets along the Pacific coast of California and Mexico kill hundreds of Loggerhead sea turtles every year.

Climate change

Climate change would cause an increase in the temperatures of sea turtle nesting beaches- which could lead to big changes for sea turtles. Because sea turtles are reptiles, they rely on the temperature of the sand around them while their eggs incubate to determine the gender of the hatchling in a nest. Typically, the eggs in cooler temperatures will become males, while the eggs in warmer temperatures will become females. With increasing nest temperatures, scientists predict that there will be more female than male hatchlings, creating a significant threat to genetic diversity.

Climate change can also cause sea levels to rise which would impact where sea turtles can build nests and lay their eggs. Sea turtles lay their eggs on the sand and therefore, rising sea levels dwindling beach sizes would give sea turtles less room to lay their eggs. They may be forced to build their nests in areas where there is more human traffic. This could result in most eggs being broken or disrupted by humans walking around them- even if accidentally. Or, the diminished shoreline could have more may lead to more eggs having to be near the water line and getting inundated and drown before there are even hatched.

Potential solutions

A potential way to reduce turtles being caught in fishing nets is using visual cues. It has been found that visual cues could play an important role in sea turtle foraging behavior and likely influence their interactions with fishing gear. Altering these visual cues for the sea turtles may be a useful strategy to reduce the accidental bycatch of sea turtles in various fisheries. Green LED light sticks attached to gillnets can reduce sea turtle bycatch by about 64% — without affecting the catch of desired fish as well as using shark-shaped objects to scare the turtles away from the nets. However, the shark-shaped objects may also scare the desired fish away from the nets. The green LED lights would have a stronger affect on the deterring of sea turtles from fishing nets.

References

• Mazaris, Antonios D., et al. “A Global Gap Analysis of Sea Turtle Protection Coverage.” Biological Conservation, vol. 173, 2014, pp. 17–23., https://doi.org/10.1016/j.biocon.2014.03.005
  • This is a scholarly article.
• Valdivia, Abel, et al. “Marine Mammals and Sea Turtles Listed under the U.S. Endangered Species Act Are Recovering.” PLOS ONE, vol. 14, no. 1, 2019, https://doi.org/10.1371/journal.pone.0210164.
  • Scholarly article
• Pham, Alexander. “6 Sea Turtle Species Endangered by Climate Change and Human Activity.” Earth.Org, Earth.Org, 9 Nov. 2022, https://earth.org/sea-turtle-species-endangered/#:~:text=Green%2C%20Hawksbill%2C%20Kemp's%20Ridley%2C,except%20the%20Arctic%20and%20Antarctic.
  • Article from website dedicated to bringing awareness to Climate Change and conservation efforts.
• Sarmiento-Ramírez, Jullie M., et al. “Global Distribution of Two Fungal Pathogens Threatening Endangered Sea Turtles.” PLoS ONE, vol. 9, no. 1, 2014, https://doi.org/10.1371/journal.pone.0085853.
  • Scholarly article
• Eckert, K. L., K. A. Bjorndal, F. A. Abreu-Grobois, and M. Donnelly (Editors). 1999. Research and Management Techniques for the Conservation of Sea Turtles. IUCN/SSC Marine Turtle Specialist Group Publication No. 4.
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• “Sea Turtle.” WWF, World Wildlife Fund, https://www.worldwildlife.org/species/sea-turtle#:~:text=Over%20the%20last%20200%20years,as%20bycatch%E2%80%94in%20fishing%20gear.
  • Article to raise aware for sea turtle conservation
• Lewison, Rebecca L.; Crowder, Larry B.; Read, Andrew J.; Freeman, Sloan A. (2004-11-01). "Understanding impacts of fisheries bycatch on marine megafauna". Trends in Ecology & Evolution. 19 (11): 598–604. doi:10.1016/j.tree.2004.09.004. ISSN 0169-5347.
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• Fisheries, NOAA (2021-02-22). "Fishing Gear: Gillnets | NOAA Fisheries". NOAA. Retrieved 2023-04-06.
• Fisheries, NOAA (2022-01-24). "The Cost of Saving Sea Turtles from Gillnets | NOAA Fisheries". NOAA. Retrieved 2023-04-06.
• "Measuring Sea Turtle Casualties by Longline Fishing". Duke Today. Retrieved 2023-04-07.
• Chuenpagdee, Ratana; Morgan, Lance E.; Maxwell, Sara M.; Norse, Elliott A.; Pauly, Daniel (2003-12). "Shifting gears: assessing collateral impacts of fishing methods in US waters". Frontiers in Ecology and the Environment. 1 (10): 517–524. doi:10.1890/1540-9295(2003)001[0517:SGACIO]2.0.CO;2. ISSN 1540-9295.
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