The number of ridleys nesting during an arribada is difficult to count, although methodologies to estimate arribada size have been developed that are useful if nesting is well supervised by competent biologists. On the other hand, estimates by laymen of numbers of turtles in a given arribada are probably so inaccurate as to be useless. 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. Human Impacts on Olive Ridley Sea Turtles Pesticides, heavy metals and PCB's have been detected in turtles and eggs, but the effect on them is unknown.
Marine turtles are at risk when encountering an oil spill.
Respiration, skin, blood chemistry and salt gland function are affected. Olive ridley turtles eat a wide variety of marine debris such as plastic bags, plastic and styrofoam pieces, tar balls, balloons and raw plastic pellets. Effects of consumption include interference in metabolism or gut function, even at low levels of ingestion, as well as absorbtion of toxic byproducts. In areas where recreational boating and ship traffic is intense, propeller and collision injuries are not uncommon. All rights reserved.