The following diagram is a model of how a dramatic decrease in egg numbers may continue for decades before it manifests itself at the nesting beach. There may be no visible signs of population decline on the nesting beach because while no new hatchlings would enter the population, adults having reached sexual maturity would continue coming to nest for a number of years. As a result, the general public often remains ignorant of the fact that loss is occurring.

The destruction of nesting habitat makes it increasingly difficult for nesting female sea turtles to sustain the population.

This figure represents the destruction of a green turtle nesting population through over-harvest of eggs — as is occurring in many parts of south-east Asia and elsewhere. For this model, females are assumed to take 20 to 50 years to reach adulthood (National Research Council, 1990) and then to remain reproductively active for about 20 years (Carr et al., 1978). The diagram illustrates how harvesting 100% of the eggs would destroy the population “from the bottom up” because no new hatchlings would enter the population.