Monitoring the Health and
Conservation of Marine Mammals,
Sea Turtles, and Their Ecosystems
A. Alonso Aguirre
Todd M. O'Hara
Terry R. Spraker
David A. Jessup
Marine ecosystem health is a relatively new and poorly defined concept. The enormous biological diversity harbored by the oceans and the lack of taxonomic and ecological studies limit our ability to define a healthy marine ecosystem. It is generally agreed, however, that healthy ecosystems are those that have stable, or at least not declining, species abundance and diversity; do not have obvious environmental degradation, frequent pollution events, or unsustainable harvests; do not have a high frequency of emerging or reemerging diseases/intoxications with negative implications for human and wildlife health; and do not have frequent die-offs or similar stochastic events, particularly those involving “indicator” or “keystone” species.
Marine ecosystems are undergoing multiple concurrent stressors that are clearly affecting marine vertebrate health. The relatively recent, drastic accelerated transformation of coastal ecosystems in most instances has not been quantified; however, the loss of critical habitat is apparent worldwide. As coastal areas are developed, marine species tend to concentrate in smaller feeding, mating, nesting, or haul-out areas, making them more susceptible to human fisheries interactions, infectious agents, algal blooms, and environmental pollution.
The scale of the oceans makes it impossible to assess the health status of the marine environment in its entirety. Even focal subsets of marine areas such as the Hawaiian Islands or the California coast do not diminish issues of scale. Adequate scientific investigations and monitoring programs are necessary on a global scale to assess the present and future health of these fragile ecosystems. Nationwide resource agencies, universities, and nongovernmental organizations are attempting to move toward the management of ecosystems and their health while incorporating the traditional concept of individual species management.