Sea Turtle Species Profiles

Hawksbill Sea Turtle

Scientific Name: Eretmochelys imbricata

 

IUCN/Conservation Status: Critically Endangered - Hawksbill sea turtles are considered to be Critically Endangered by the International Union for the Conservation of Nature (IUCN). This means this species is at high risk of extinction in the wild. In the United States, the hawksbill is considered Endangered under the Endangered Species Act and is also protected from harvest in Cuba, Mexico, The Bahamas, and Bermuda. Hawksbill sea turtles are protected from commercial trade under CITES, the Convention on International Trade in Endangered Species. Protections from commercial trade are critical for this species due to the trading of hawksbill shells that still occurs in some countries today. Hawksbills do not typically nest on any beaches of the U.S. Because hawksbills in U.S waters have traveled from the waters of other countries, the Inter-American Convention for the Protection and Conservation of Sea Turtles (IAC) is important in protecting this species (Witherington & Witherington, 2015).

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Habitat and Distribution: Hawksbill sea turtles are mainly spongivores, having a diet consisting largely of sea sponges. Because of their diet, the distribution of hawksbills follows that of coral reefs. They are found in tropical and subtropical areas. Most hawksbills near the U.S. are found in the waters of South Florida (Witherington & Witherington, 2015).

Diet: Hawksbills spend their first few years as opportunistic feeders, eating things such as dead insects, blue buttons, copepods, and hydroids. As they age, they use their specialized beak and long neck to eat mainly sponges and invertebrates from crevices on coral reefs. It is estimated that once they reach adulthood, sponges may comprise up to 95% of their diet. Fun Fact: The sponges that hawksbill sea turtles feed on are toxic, however, these toxins do not harm the turtles but instead bioaccumulate in their bodies, making their meat toxic to potential predators and humans (Witherington & Witherington, 2015).

Size: The carapace of an adult female hawksbill is between 76 to 89 centimeters (30 to 35 inches) and she will weigh between 100 and 150 pounds (Witherington & Witherington, 2015).

Distinguishing Characteristics: Hawksbill sea turtles can be identified by their 4 lateral scutes, which slightly overlap, similar to shingles on a roof. The scutes of a hawksbill are known for their colorful, plastic-like appearance and a wide variety of colors. Their scutes can have quite a bit of variation and can range from dark brown with lighter markings to lighter shades of brown. The beak of a hawksbill is where this turtle gets its name. It is narrow and strong, used for scraping sponges and other invertebrates off of reefs and crevices on coral reefs (Witherington & Witherington, 2015).

Maturity and Reproduction: Hawksbills reach maturity at about 25 years of age. Males and females mate along migration pathways and most hawksbills clutches have a single paternity (Witherington & Witherington, 2015).

Nesting: In our region of the world, hawksbill nesting takes place on tropical beaches in the southern Gulf of Mexico and the Caribbean. Hawksbills do not nest in incredibly high densities anywhere in the world. A female hawksbill will lay on average around 140 eggs, which will incubate for about 2-2.5 months. Females nest every 3 to 4 years and return to their natal beach to lay 3 to 5 nests. Hawksbill sea turtles do not nest in Florida. Hawksbill nesting season is from May to October (Witherington & Witherington, 2015).

Conservation and Specific Human Impacts: It is estimated that hawksbill nesting has decreased about 80% in the past century. The major reason for the serious decline in hawksbill populations is commercial harvesting. In the past, hawksbills have been harvested commercially for their unique shells and scutes. Originally, the tortoiseshell pattern we often see in glasses, jewelry, and other accessories came from harvested hawksbill shells but has now been replaced by plastic. These scutes are malleable and can be heated to be crafted into unique shapes. These items, as well as taxidermied hawksbills, used to be sold in tourist gift shops, which still happens in some countries today. Because of the Convention on International Trade in Endangered Species, trade of tortoiseshell has decreased. However, it has not completely stopped and illegal harvest and trade still do occur (Witherington & Witherington, 2015).

 

Citations:

Witherington, B., & Witherington, D. (2015) Our Sea Turtles: A Practical Guide for the Atlantic and Gulf, From Canada to Mexico. Pineapple Press, Inc.