OLIVE RIDLEY TURTLE 



Common Name: OLIVE RIDLEY TURTLE 

 Scientific Name: Lepidochelys olivacea 



Listing Date: 07/28/78 



Species Status: Endangered 



Species Trend: Decreasing 



Current Estimated Population: Unknown 



SPECIES POPULATION STATUS 



Because of the continued existence of several large nesting aggregations or "arribadas", it is 

 probable that the olive ridley is, in terms of absolute numbers of adult individuals in existence, 

 the most abundant sea turtle species in the world. Nevertheless, there is evidence of downward 

 trends at several arribada beaches. The various populations are under considerable stress, and the 

 concentration of such a large proportion of the reproductive animals into a few arribadas may be 

 a liability, not only in that such aggregation facilitates industrial-scale exploitation, as it has in 

 Mexico as well as on the feeding grounds in Ecuador, but also because arribadas do not seem to 

 be an efficient method of guaranteeing maximum reproductive efficiency. Indeed, at the 

 relatively undisturbed arribada beach of Nancite. within Santa Rosa National Park, Costa Rica, it 

 has been estimated that only about 5 % of eggs laid actually produce hatchlings. 



Because nesting in successive years is commonplace for olive ridleys, and may well be the norm 

 for the species, the erratic nesting population trend lines often shown by loggerhead or green 

 turtle populations, that very rarely nest in successive years, are not shown by olive ridley 

 populations. It is thus much easier and more justified to draw conclusions about overall ridley 

 population trends from a few years of comprehensive nest counts than it is for those species with 

 multi-year nesting cycles. 



Olive ridley populations in the western Atlantic are very low and continue to decline, almost 

 certainly as a result of long-standing incidental capture in shrimp trawls. Available data are too 

 few to assess the survival status of the species in the eastern Atlantic and northern Indian Oceans; 

 however, these populations appear to be stressed. In the eastern Pacific, data indicate that some 

 nesting aggregations are in decline, while others appear relatively stable. 



SPECIES BIOLOGY 



The olive ridley is the smallest of the sea turtles and named for the olive color of its heart-shaped 

 shell. The species may be identified by the uniquely high and variable numbers of vertebral and 



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