Variation in Sea Turtle Life History Patterns: Neritic vs. Oceanic Developmental Stages
In this chapter, three generalized sea turtle life history patterns are identified and evaluated with respect to phylogenetic relationships and reproductive traits. Characteristics of the developmental stages (oceanic vs. neritic) and adult foraging stage (oceanic vs. neritic) are the primary differences that distinguish the three patterns. These variations are reviewed, the consequences of oceanic vs. neritic developmental stages are discussed, and finally, speculation about how these differences may have evolved is presented. The dramatic decline in sea turtle populations and the extensive degradation of their ecosystems make it difficult to determine the functional roles of sea turtles in their ecosystems (see Chapter 10), and therefore, it is difficult to evaluate the selective factors that led to the present-day sea turtle life history patterns. It is particularly difficult, in the context of massive faunal declines and food web alterations, to speculate on the relative importance of the evolutionary pressures from competition for resources and predation that may have resulted in these observed life history patterns.