Kemp's ridley sea turtle

Kemp's ridleys live in the sea near Mexico and the United States.

They like shallow water with sandy or muddy bottoms.

Kemp's ridleys live mostly in the gulf between Mexico and the United States. Young turtles also live along the Atlantic coast of the United States, some as far north as Nova Scotia in Canada. Grown-up turtles stay mostly in shallow coastal water with sandy or muddy bottoms, where crabs live.

A few have turned up much farther away, near Europe and in the Mediterranean Sea, but that is rare.

The IUCN calls its distribution one of the most restricted of all sea turtles: coastal areas throughout the gulf between Mexico and the United States and along the US Atlantic coast, with rare occurrences off Atlantic Canada and Europe, Bermuda, the Azores, Madeira and in the Mediterranean Sea. Coastal waters of the gulf are developmental and foraging habitat and migratory corridors for adults, juveniles regularly use the US Atlantic coast, and offshore oceanic waters hold hatchlings, post-hatchlings and juveniles.

NOAA Fisheries adds that adults mainly use nearshore waters with muddy or sandy bottoms, that juveniles reach Nova Scotia, and that females migrate after nesting to foraging areas from the Yucatán Peninsula to southern Florida. In Texas, the National Park Service says they occur in nearshore waters, bays and passes.

Kemp's ridleys love crabs.

They also eat fish, jellies and shellfish.

Grown-up Kemp's ridleys hunt mostly crabs on the seafloor. They also eat some fish, sea jellies and mollusks.

Baby turtles eat something different. For their first one or two years they drift among floating seaweed called sargassum far out at sea, where they rest, hide and feed on small animals and plants.

NOAA Fisheries says that once Kemp's ridleys settle in shallow coastal areas, crabs are their preferred food, and that adults use muddy or sandy bottoms where that prey is found. Padre Island National Seashore lists the diet as primarily crabs, with fish, sea jellies and mollusks (Shaver 1991; National Marine Fisheries Service 2020).

Hatchlings swim rapidly offshore; some stay in currents within the gulf while others are carried around Florida into the Atlantic by the Gulf Stream. Juveniles shelter and feed on small animals and plants in floating Sargassum algae for 1 to 2 years, or until they are about 8 inches (20 centimeters) long, before moving to nearshore waters (NOAA).

Many mother turtles come to the beach together.

This big group is called an arribada.

They nest in the daytime!

Kemp's ridleys have a surprising way of nesting. Female turtles gather offshore, then crawl onto the beach together in big groups called arribadas, a Spanish word meaning "arrivals." Only one other turtle, the olive ridley, does this. Scientists still do not know for sure what starts an arribada.

Kemp's ridleys are also the only sea turtles that usually nest during the day. Scientists think that when so many babies hatch together, predators may not be able to catch them all, so more of them survive.

NOAA Fisheries describes arribada nesting, in which large groups of females gather offshore and come ashore together; it is found only in the genus Lepidochelys (Kemp's and olive ridleys). Proposed triggers include offshore winds, lunar cycles and female pheromones, but none is confirmed. Group nesting may defend against predators, or reflect environmental factors, and large numbers of hatchlings entering the sea together may overwhelm predators. NOAA calls Kemp's ridley the only sea turtle that routinely nests during the day; the National Park Service suggests daytime nesting may make it harder for nocturnal predators such as raccoons to find nests.

At sea, some males migrate each year between feeding and breeding grounds while others do not migrate at all, and some females return to the same foraging grounds year after year (NOAA).

Kemp's ridleys almost disappeared.

People protected their nests and changed fishing nets.

Now there are more of them, but they still need help.

Kemp's ridley is critically endangered. In 1947, a film showed tens of thousands of females nesting on one beach at Rancho Nuevo, Mexico, in a single day. By 1985 only 702 nests were found all year. People had taken many eggs, and many turtles were caught by accident in fishing nets.

Mexico and the United States worked together: they guarded nests and required special escape hatches, called turtle excluder devices, in shrimp nets. Nest numbers rose about 15% a year until 2009, then stopped rising in 2010. Fishing gear, pollution, oil spills and cars driving on nesting beaches are still dangers.

Wibbels and Bevan assessed Lepidochelys kempii as Critically Endangered (A2bd) for the IUCN Red List (assessed 14 January 2019, published 2019): a single population, about 71.2% of nesting on 30.4 kilometers of beach at Rancho Nuevo, Tamaulipas, and a reduction of 82.6 to 88.3% over three generations from the numbers estimated from a 1947 film. Egg collection, fisheries bycatch and nest predation drove the 1947 to 1985 collapse; nest protection and turtle excluder devices in trawl gear brought exponential growth from about the mid-1990s to 2009, and whether the post-2010 slowdown is temporary is unknown. The IUCN estimates 22,341 mature individuals from 2016 to 2018 nest counts and lists threats led by fisheries, predation, cold stunning, pollution and debris, climate change and oil spills.

NOAA Fisheries records a low of 702 nests in 1985, about 15% annual growth through 2009, and bycatch as the biggest continuing threat; the species has been listed as endangered under US law since 2 December 1970 (IUCN).