5: Respect ecosystem integrity

Keeping all the parts of an ecosystem and not adding new ones is a critical part of having a healthy working ecosystem. Taking actions that help to keep important parts (like whales or certain habitats) and not introducing new parts (like non-native species) is part of designing a healthy ecosystem.

Keeping all of the parts of an ecosystems means not just keeping all the species, but also a full range of size and age classes of those species. Removing large adult female rockfish removes those animals with the greatest reproductive capacity. Photo: J. Nichols

Intact ecosystems are more than the sum of their parts. Processes and forces that bind the parts into a system produce synergies and properties that the individual parts do not possess when simply collected together.

Ecological integrity, in which a system has all its parts and no "extra" ones, is a hallmark of environmental health. An intact ecosystem has a complete suite of species, and a full range of size and age classes of each component species.

Ignoring the ecological integrity and the power of biological interdependence in marine systems has been catastrophic. Historically, fishery practices targeted predators and preferentially removed old, large organisms (those with the greatest reproductive capacities), while relying on smaller, rapidly growing and barely reproducing younger animals for replenishment. As a consequence fishery collapses became widespread. But the ecosystem wide impacts were just as disastrous. Because predators mediate competition among prey species and help assure that a few, fit individuals of all kinds survive to produce another generation, such single-species management strategies not only doomed targeted populations to death spirals, but also triggered trophic cascades with ecological effects that persisted for decades and involved hundreds of species.

Adding, or introducing, invasive species, toxic materials, and pathogens also reduces ecological integrity. In the Salish Sea, non-native species like the purple varnish clam likely were introduced in ballast water. Other species, like the Japanese seaweed Sargassum muticum, likely were introduced with the intentionally introduced Pacific oyster, and now compete with native kelp, impacting benthic subtidal communities.

The ocean, a historical out-of-sight-out-of-mind dumping ground for industrial waste, now bears the burden of tonnes of organochlorines and other persistent organic pollutants that have bioaccumulated in the food chain and impacted the health of top predators.  The Salish Sea’s resident and transient killer whales are considered some of the most contaminated cetaceans in the world.