A Historical Perspective of the Biology and Conservation of the Kemp’s Ridley Sea Turtle
The history of the critically endangered Kemp’s ridley sea turtle (Lepidochelys kempii) has presented scientists and conservationists with a variety of questions and challenges originating in part from the species’ limited distribution and single primary nesting beach. Although the species was initially brought to the attention of the scientific community in 1880 by Richard Kemp, more than 80 yr passed before Henry Hildebrand revealed the location of its primary nesting beach at Rancho Nuevo, Mexico in the western Gulf of Mexico. By the time scientists began estimating the number of females nesting at Rancho Nuevo, it appeared that the species had declined when compared with the relatively large mass nesting (a.k.a. arribada) filmed by Andres Herrera in 1947. This decline appeared to be due to historic exploitation of turtles and their eggs on the nesting beach and accidental capture in the Gulf of Mexico shrimp fishery. Despite the implementation of conservation measures at Rancho Nuevo, the species continued to decline until the mid-1980s. The continued protection of females and nests on the nesting beach, the decline in shrimping effort in the Gulf of Mexico, and the implementation of turtle excluder devices resulted in a significant increase in the number of females nesting during the 1990s, and an exponential recovery rate. Since 2010, the recovery rate has unexpectedly deviated from its exponential trend and sharp declines have been documented in some years. The underlying cause(s) of the recent decline is unclear.