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Hawksbill Turtle - A Critically Endangered Species
Hawksbill turtles are one of the most Critically Endangered (CR) species in the world and they are the only existent species in their genus. Their characteristics, habitat, food, breeding pattern, threats, conservation efforts and other information have been discussed here.
The IUCN has been reassessing the status of these species since 1982 when it started off as a threatened species and then was upgraded to critically endangered in 1996. This was due to an eighty percentage decline of the turtle population within three generations with no satisfactory increase in population. They are found in the tropical oceans all over the world and can be seen mostly near the coral reefs.
Their scientific name is Eretmochelys imbricata
Abbreviations and terms explained:
CITES – Convention on International Trade in Endangered Species
IUCN - International Union for Conservation of Nature
WWF – World Wildlife Fund
MPA - Marine Protected Areas
TRAFFIC - Wildlife trade monitoring network
Carapace – Hard outer covering or case of certain organisms such as arthropods and turtles
By-catch - Unwanted marine creatures that are caught in the nets while fishing for another species
Scute - Large bony plates as on a turtle
Scientific Classification (Taxonomy):
Characteristics and Behaviour of the Hawksbill Turtle:
- The Hawksbill turtles resemble other marine turtles and have a narrow pointed beak resembling the bird “Hawk” that gives them this name.
- The scales on their shells overlap and this gives a serrated look (saw-like) on the margins of the scales.
- Their body is flat with a protective carapace that has an amber background with irregular light and dark streaks all over. The carapace has five scutes in the central part and four pairs of scutes on the lateral part (please see diagram to the right). The posterior scutes overlap and give a serrated look that resembles a saw. Their shells change colour slightly depending on the temperature of the water.
- The pattern and colours on their shell are strikingly beautiful. The top shell is dark to golden brown with streaks of orange, red or black and the bottom shell is yellow. Males have brighter colouring than the females.
- There are two pairs of prefrontal scales on the top of their head (it can be seen clearly in the pictures).
- They have arms like flipper that help them to swim in the ocean and each flipper has two claws (please have a look at the pictures).
- They have a tail.
- An adult hawksbill turtle grows up to 1 m long (males mature when they are around 70 cm long and females mature when they are around 80 cm long) and weighs around 45 to 70 kg. Some huge hawksbill turtles can weigh up to 90 to 120 kg.
- They need to come to the surface of water in order to breathe
Habitat and food of the Hawksbill Turtle:
- The hawksbill turtles are found in the tropical oceans (Indian, Atlantic and Pacific) near the coastlines (helps with nesting process easy) all over the world, but mostly near the coral reefs. For example, the Mesoamerican reef, Coral Triangle, Coastal East Africa
- It spends more time in coral reefs and lagoons than in the open ocean and can be usually seen resting in caves and ridges that are in and around the reefs. They mostly rest in the same spot every night.
- They have a wide range of habitat from open oceans to lagoons and mangrove swamps as they are highly migratory.
Food of the Hawksbill TurtlesClick thumbnail to view full-size
- It is assumed that the young ones remain at sea till they completely mature.
- The hawksbill turtles are omnivores and they feed on sea-sponges which are their main food (70 to 95%) and sometimes feed on algae, molluscs, crustaceans, sea urchins, fish, cnidarians like sea anemones and jellyfish, soft corals, sea squirts, sea grass, sea weeds, squids and shrimps. Their pointed beaks help them to extract these from the crevices of the coral reef. They sometimes also feed on dangerous jellyfish like hydrozoan and Portuguese man o’war. Due to it feeding on venomous cnidarians, its flesh can be toxic, but the hawksbills themselves are resistant to the toxicity of their prey.
- Hawksbill turtles are solitary and they meet only during mating period.
- They do not have many predators due to their hard and serrated carapaces and the few predators are sharks, octopus, some fish, humans and crocodiles in estuaries.
Reproduction in Hawksbill Turtle:
- Mature hawksbill turtles breed and nest every two to three or four years in lagoons (shallow waters near the coast) that are in remote islands within their range. They also look for remote areas in the islands.
Hawksbill Turtle laying eggs. Nesting Turtle
- After mating, the females go into the beach during the night, clean up an area and dig a hole with their rear flippers. This is called the nesting hole. They sometimes travel up to 2400 km between feeding and breeding grounds
- They lay batches of eggs (up to 140 eggs and very rarely up to 200 eggs) and cover them with sand and then return back to the sea. This happens every 14 to 16 days during the nesting season with generally 3 to 5 nests every season.
- Nesting takes between 1 and 1.5 hours. Nesting period is usually between April and November, but can sometimes change for different locations across the world.
- Baby turtles hatch after around two months and they hatch in the night. They are around 4 cm long (carapace length), weigh around 24 gm and are dark coloured. Their carapace is heart shaped and increases in length as they mature. They crawl into the sea and any baby turtles left on the beach at daybreak are preyed upon by shorebirds like sea gulls, crabs and other predators.
- Their life history can be divided into pelagic (oceanic) phase (lasts for 1 to 4 years and this phase starts from the time of hatching to when they are about 20 to 35 cm long), benthic (relating to or happening on the bottom under a body of water, where they move to areas in search of food) phase and reproductive phase (when they are mature and ready for reproduction).
- During the pelagic phase, they take shelter in the floating algae and also mostly feed at the surface on plankton, fish eggs, barnacles (Marine crustaceans), tunicates (Primitive marine animal), algae.
- During the benthic phase, the immature turtles move to coastal areas and start feeding below the surface on animals in the coral reef environments.
- When the young ones are around 35 cm long, they switch from pelagic lifestyle to benthic lifestyle by living in coral reefs.
- Various factors are responsible for a hawksbill turtle’s maturity, like the habitat, individual genetics, quantity and quality of food, population density in that particular habitat, etc. Size and age do not matter.
- Once they are mature, they enter the reproductive phase and are ready for reproduction.
- The lifespan of these turtles in the wild is estimated to be between 30 to 35 years.
Note: Turtles in Caribbean area are known to attain maturity between 10 to 25 years while the ones in the Indo-Pacific region attain maturity between 30 to 35 years.
Importance of the Hawksbill Turtle:
- They are a source of income through tourism.
- The health of the coral reef and sea grass beds are maintained by the hawksbill turtles.
- They remove the sponges that they feed on from the coral reef surface and this helps the reef fish get better access to food.
Main threats and endangerment for the Hawksbill Turtle:
- The most dangerous threat is fishing by humans. They are highly susceptible to getting entangled in gill nets
- Getting caught in fishing hooks accidentally, they get drowned as they cannot reach the surface of the water to breathe.
- Their shells are sold as “tortoiseshells” in the market (Wildlife trade or shell trade).
- Decrease in the nesting areas, excessive egg-collection and decrease in feeding habitats are another threat
- Global climate change is impacting coral reefs in a negative manner, with increased chances of coral diseases.
- Toxic spills and vessel groundings, pollution, coastal development, etc., are all leading to the degradation of habitat quality
- Fishery related mortality in the process called by-catch which is a serious threat to hawksbill turtles
- Their beautiful brown shells and yellow carapace plates are manufactured into jewellery and ornaments and they are of high demand in the market. For example, Chinese use these shells for decoration; Japanese harvest these for their shell scutes and also use them in making eye-glass frames and frames for a traditional Japanese musical instrument. Ancient Greeks and Romans used these shells to make jewellery, combs, brushes and rings.
- There is still demand for other hawksbill products like leather, oil, perfumes, cosmetics, etc.
- Whole stuffed turtles were sold as rare collections to the tourists.
- Their flesh and eggs are eaten as delicacies in some parts of the world, although it is illegal to hunt them. Also the flesh have toxic chemicals which are not good for the humans and consuming this can cause serious illness and can be lethal.
- Using the nesting beaches for recreations and commercial purposes, camping, fires, litter and other human activities affect nesting of hawksbills.
- Hawksbill turtles grow, mature and reproduce slowly.
- Small mammals like mongooses and other predators including humans raid the nest and dig up eggs right after they are laid.
- Increase in levels of oceans can also affect the nesting habitat as it leads to beach erosion.
- Beach lightings can disorientate the hatchlings from going into the ocean
Conservation efforts for the Hawksbill Turtle:
- Conservation efforts are taken and protected by international treaties and agreements as these hawksbill turtles are not native to just one country, but widespread over the world.
- In many areas, satellite tags (do not harm turtles and they are fall off after some time) are placed on marine turtles (Satellite telemetry) by the WWF to collect information about them, like their feeding areas, migration patterns, contact with fisheries and fishery equipment. This helps them to develop management strategies, create protected areas and to identify threats.
Critically endangered Hawksbill Turtle
- They are under the protection of the CITES of Wild flora and Fauna, but still there is a large amount of illegal trade related to hawksbill shells and products.
- WWF is working with the communities to help reduce turtle harvesting and other turtle trades in the Coral Triangle.
- Awareness workshops are conducted in Malaysia to inform people about the threats for the hawksbill turtle and the importance of protecting them.
- Local people are helped with alternate livelihoods, so that they no longer depend on turtle trading for their income.
- WWF works alongside TRAFFIC to stop illegal trade of hawksbill products and to train and equip local rangers about protecting these turtles and their nesting beaches from poaching and egg-collecting.
- They also help conservationists with equipment for monitoring and patrolling turtle nests in many parts of the world.
- WWF is working with the fisheries industries on reducing by-catch by using turtle friendly hooks and gillnets that have devices to exclude turtles.
Books on Hawksbill turtles
- Turtle movements are monitored by the WWF with the aid of satellites and these help reduce fisheries processes interaction with the turtles.
- WWF also helps fishermen in saving turtles that get caught in fishing equipment
- MPAs are created all around the world by the WWF so that the turtles can feed, nest and migrate safely and without any trouble.
- WWF is working on protecting nesting sites and takes actions to handle climate changes.
- It is now illegal to import or export turtle products, to kill turtles, capture turtles or harass them.
- The US government has laid recovery plans to protect the hawksbill turtles. Citizens are also helping to protect their eggs from predators.
Facts about the Hawksbill Turtle:
- The picture of the hawksbill turtle appears in the banknotes in the 20 bolivar Venezuelan banknotes and the 2 reais Brazilian banknotes.
- A fountain sculpture of a boy riding a hawksbill (Turtle boy) can be found in Worcester in Massachusetts.
- There are only 5 populations of hawksbill turtles worldwide.
- About 15,000 females are estimated to be nesting every year around the world.
- The largest hawksbill population in the world is the nesting colony on Milman Island in Queensland, Australia.
- Hawksbill turtle shells are the sole source for commercial tortoiseshell
- Japan imported around 33 tonnes of hawksbill (2 million in total) shell per year between 1950 and 1992, which amounts to the death of 31,000 turtles every year.
- Less than one out of 1000 eggs will survive and become mature adults.
- Gender of the hatchling is determined by incubation temperature and hence climate change will have a great impact on hawksbill turtle populations
- One hawksbill turtle can consume over 1000 pounds of sponges per year.
What can you do to help conserve the Hawksbill Turtle?
- Send a turtle to rehab
- Donate to the WWF or adopt a sea turtle
- Find your local office for the WWF here
- Help with recovery process for the thousands of sick and injured turtles
- Please do not buy products made of sea turtle parts.
- If you find a turtle report to the WWF or to the nearby environment conservationist
I hope you enjoyed reading about these beautiful turtles, as much as I enjoyed reading while researching and writing about this.
Let us all join hands and help save the turtles and our planet. There are so many other critically endangered, endangered, and threatened species all over the world. We have also lost so many species due to the destruction caused by humans.
We need to work together to stop all these destructive activities and educate our children and the younger generation about the importance of conserving and protecting our environment.