Loggerhead turtle - Threats

A dangerous cocktail of habitat loss, fisheries bycatch and pollution

Loggerheads are less likely to be hunted deliberately than other marine turtles: their meat is considered less desirable than that of the green turtle, and the shell is less prized than that of the hawksbill. However there is some direct exploitation in Cuba, and loggerheads' eggs are collected and eaten in many parts of the world.

The main cause of mortality is attributed to fisheries bycatch, and abandoned drift nets continue to drown loggerheads in unknown numbers. In the Mediterranean and the USA, habitat loss or disturbance and pollution are the main threats to this species. In Florida for example, beach "armouring" to prevent erosion, increase in human beach activity, and beachfront lighting have all affected nesting turtles.

Indirect take
In 1987, some 32,000 juvenile and adult loggerheads were captured as bycatch in the Atlantic, and 10,500 in the Gulf of Mexico. Assuming 20% mortality, this was equivalent to 640 tonnes in a year. Shrimp boats catch large numbers in their funnel-shaped nets. Many of these animals then drown.

Before the introduction of Turtle Excluder Devices (TEDs) approximately 50,000 loggerheads were killed in shrimp nets in the Gulf of Mexico and the Atlantic Ocean, perhaps ten times as much mortality as all other fisheries (seines, gill nets, traps, and longlines) combined. Although the requirement for TEDs has been legally challenged, it remains in force, and the lessons learned may develop into a model for certifying turtle-safe shrimp.

Loggerheads also drown after taking baited hooks, or are severely wounded after becoming entangled in longlines. In 1991 between 10 and 40% of swordfish longline fishing trips in the Ionian Sea, Greece, snared between 1 to 3 loggerhead turtles.

Although the use of drift nets on the high seas has declined worldwide since a 1992 United Nations ban, they have killed thousands of loggerheads which are particularly vulnerable given their migratory behaviour.
Find out more about bycatch