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A long‑term study in Cabo Verde has found that female loggerhead turtles are breeding earlier but less frequently because warming oceans are altering their feeding grounds. The research highlights how climate change and declining marine productivity threaten the reproductive success of this already vulnerable species.
Background
The loggerhead turtle (Caretta caretta) is named for its large head and powerful jaws, which enable it to crush hard‑shelled prey like conchs and whelks. It is the world’s most widespread sea turtle, nesting across the Atlantic, Indian and Pacific Oceans and the Mediterranean Sea. Adults weigh about 200–350 pounds (90–160 kg) and measure 2.5–3.5 feet (80–110 cm) in shell length. Females reach sexual maturity at about 30 years and return to their natal beaches every 2–3 years to lay multiple clutches of eggs. The species is listed as Vulnerable on the IUCN Red List.
Habitat and threats
- Wide distribution: Loggerheads inhabit coastal bays, lagoons, estuaries and open oceans. Major nesting sites include the southeastern United States (especially Florida), the Cape Verde Islands, Oman, Western Australia, eastern Australia and Japan. Juveniles drift with floating Sargassum mats before recruiting to coastal feeding grounds.
- Threats on land: Coastal development, beach armouring and artificial lighting degrade nesting habitat. Eggs and hatchlings are preyed upon by raccoons, dogs and birds.
- Threats at sea: Loggerheads are harmed by pollution, marine debris, ship strikes and bycatch in fishing gear such as trawl nets and longlines. Climate change affects ocean currents, prey availability and sand temperatures that determine hatchling sex ratios.
- New research: The 17‑year Cabo Verde study found that warmer sea surface temperatures cause females to arrive and nest earlier, but declining ocean productivity forces them to wait longer between breeding seasons. The remigration interval has doubled from about two to four years, and turtles are building fewer nests with fewer eggs.
Conservation efforts focus on protecting nesting beaches, reducing bycatch through turtle excluder devices, and safeguarding feeding habitats. Addressing climate change and marine ecosystem health is critical to ensure the long‑term survival of loggerhead turtles.
Source: The Hindu
