Larribada

Larribada, from the Spanish term meaning arrival, is the name given to a mass nesting event in which large numbers of sea turtles come ashore to nest on the same beach within a short period. The phenomenon is most closely associated with the olive ridley sea turtle (Lepidochelys olivacea) and is particularly well documented on Pacific coast beaches of Central America and Mexico, such as Ostional in Costa Rica and Rancho Nuevo in Mexico.

During an arribada, hundreds to thousands of females may emerge from the sea on successive nights to dig nests, lay eggs, and return to the ocean. The timing and duration of the event can span several days to a few weeks, and nocturnal activity often coincides with favorable tides and sea conditions. Eggs incubate for roughly 50 to 60 days, after which hatchlings emerge in waves and head toward the open ocean. The high-density nesting is thought to be an adaptive strategy that can increase hatchling survival through predator satiation, though it can also heighten vulnerability to nest disturbance and human pressures.

Conservation and management contexts vary by location. Olive ridley populations are affected by threats such as habitat loss, bycatch in fisheries, and climate-related changes in nesting beaches and hatchling sex ratios. Some beaches are subject to regulatory egg collection by local communities, a practice balancing subsistence needs with conservation goals. Larribadas remain a focus of ecological research and coastal wildlife management and are a striking example of a reproductive strategy in sea turtles.