Pristine Atoll Shows Hope for World’s Oceans

March 9, 2012

By Mark Tercek

Degraded coral reefs, depleted fish stocks, increasing competition for marine resources and space: the challenges facing our oceans can seem daunting.

The world’s oceans are heavily impacted by humans.  Despite being the largest habitat on earth, no ocean is without our presence. We are on our way toward losing up to 70 percent of coral reefs by 2050.  Entire food webs have been upended in our pursuit of big fish. Coastal development and destructive fishing practices have contributed to the loss of 85 percent of oyster reefs globally.

We have forgotten what an untouched ocean looks like.  

There are, however, a few spots on earth so remote that the oceans teem with life in conditions similar to pre-industrial times.

One of those places is Palmyra, an isolated atoll 1,000 miles south of Hawai’i. My organization, The Nature Conservancy, purchased the Atoll in 2000 after others tried to buy it to use as a nuclear waste dump and a casino. Other than a brief stint during World War II when the US Navy used it as an air refueling station, Palmyra has essentially remained free of people throughout history.

When much of our attention is focused on minimizing manmade threats to our oceans, what can we learn from an uninhabited spot like Palmyra?

A lot, it turns out. Free of most of the damage usually caused by people—pollution, overfishing, development, and nutrient runoff—Palmyra provides a baseline for what a healthy marine system looks like.

We’re discovering that healthy marine ecosystems have far more predators at the top of the food chain than had been previously realized, thanks to collaborative research with the U.S. Fish and Wildlife Service and the Palmyra Atoll Research Consortium. We now know that lots of sharks mean strong reefs and healthy fish populations.

Studies have shown that sharks and other large predators comprise more than half of the fish biomass around Palmyra. In contrast, marine systems that have been subjected to human development, pollution, and overfishing tend to be dominated by small plankton-eating fish and algae. 

Palmyra resets our thinking on what an intact marine system should look like. I experienced that realization firsthand while diving with research scientists on the Atoll and coming face-to-face with a 15-foot shark.  Dozens of smaller sharks surrounded us, yet they left us alone. 

Those sharks are an important reminder of the crucial role species at the top of the food chain—known as apex predators—play. The loss of top predators can set off a catastrophic chain of effects that reverberates through the entire food chain.  A recent study in the journal Science argues that the loss of apex predators like sharks, wolves, bears and foxes may be may be humankind’s most pervasive influence on nature.

The research that Consortium is doing at Palmyra can provide a baseline for both conservationists and fishery managers as they set goals for restoring degraded marine systems.        

Palmyra is also a good laboratory for studying the impacts of one threat the Atoll hasn’t been immune to: climate change.

For example, without pressures from human development, the 16,000 acres of coral reefs around Palmyra are doing better than those in populated areas, where climate change is “bleaching” and killing reefs around the world.

The research is encouraging.  While coral bleaching events have hit Palmyra, the bleached corals are recovering instead of dying, and new corals are quickly settling in.

Palmyra’s corals also appear to be more resilient to ocean acidification. As increasing carbon emissions change our oceans’ chemistry, corals are becoming brittle and weak. This cripples their ability to grow, reproduce, and resist disease. But Palmyra’s corals are showing less disease and are growing and reproducing more quickly than corals around developed areas.

If we can minimize threats such as overfishing and pollution, the trends we are seeing in Palmyra imply that we can give corals elsewhere a better chance of surviving the effects of global warming.

As we work to protect our oceans and the important benefits they provide to millions of people worldwide, Palmyra shows we can act now to help marine and coastal systems overcome the impacts we are seeing today. Developing sustainable fisheries, preventing pollution, and controlling agricultural run-off are all steps that communities and governments can take to help keep our oceans strong and productive.

 

Mark Tercek is President and CEO of The Nature Conservancy.

Top Image: Beautiful Palmyra Atoll Credit: USFWS, Flickr