Story highlights
- The government of Grand Cayman is considering a huge pier development plan
- Ellen Prager, Steven Miller, Carl Safina: Plan to relocate coral reefs is bad and impossible
Dr. Ellen Prager is a marine scientist, author, president of Earth2Ocean Inc. and a Safina Center fellow. Dr. Steven Miller is a senior research scientist at Nova Southeastern University Oceanographic Center. Dr. Carl Safina holds the endowed chair for nature and mumanity at Stony Brook University on Long Island, where he runs the Safina Center. The opinions expressed in this commentary are solely those of the authors.
(CNN)Once upon a time, on a small island in the Caribbean, there was a picturesque harbor and lovely town overlooking clear emerald-blue waters and spectacular coral reefs. Visitors enjoyed dining at waterside restaurants, diving, snorkeling, glass bottom boat rides and even a submarine tour of the nearby reefs. Local businesses thrived and made millions of dollars each year through tourist activities.
One day, the government decided to build a massive dock and pier to make cruise ship visits more efficient and to lure in larger vessels. They destroyed a historic shipwreck, acres of living coral reef and left the harbor water milky white from dredging.
After the giant concrete facility was put in place, visitors still came to the island, but its unique harbor, clear water and nearshore coral reefs were no more. Local dive shops, hotels and restaurants went out of business, and there were few water-based activities to enjoy in the harbor.
Scary fairy tale or potential reality?
Today, the government of Grand Cayman is considering such a huge pier development plan. If it goes through, George Town harbor and the island will be forever altered.
One reason the plan is so controversial is that it has been implied, if not directly stated by proponents, that the coral reefs, which would be destroyed, can be relocated. But there's a problem: relocating entire coral reefs is impossible. It can't be done, and the proponents of the project who suggest otherwise are wrong. Here's why:
Coral reefs are large, complex three-dimensional structures that form over thousands of years -- but only when biology, geology, chemistry and physical factors align under special circumstances.
Warm ocean temperatures, sufficient flow and salinity, a stable substrate and pollution-free water, especially as related to nitrogen and phosphorus, are prerequisites for coral reefs to grow and thrive. And relatively shallow water is important so light can sustain the symbiotic relationship between corals and the microalgae that live in their tissues.
Corals are the lead engineers on a reef, building its framework. They get help from coralline algae, which supply the cement. A diverse assemblage of organisms produces the sediment that fills in structural gaps. Fish, crustaceans, mollusks and additional invertebrates utilize the coral-built reef framework and in return graze seaweeds that can overgrow corals. These organisms also help to recycle nutrients. Residents that filter water, such as sponges, and sea cucumbers that ingest sand, help keep the reef clean.
What we see as a coral reef is the cumulative result of a special location, specific ocean conditions and the incalculable interactions of a diverse living community of organisms.
It is simply impossible to relocate a reef as proponents of the pier development plan suggest or imply.
The functional unit of a reef is not just what lives on the surface, but the three dimensional structure comprised of coral rock that in the case of George Town Harbor is comprised of building-sized units that stretch across dozens of acres.
The three dimensional structure of these reefs is renown throughout the Caribbean and world as a premier diving and snorkeling destination. There is no terrestrial analogue to such relocation activity, but moving mountains comes to mind. And even if you could relocate the coral reefs in question, the process itself would be akin to killing the patients in an attempt to save their lives. Huh?
What can be attempted, in other circumstances, is to transplant or relocate individual coral fragments or even entire colonies. This is sometimes done to repair reefs damaged by ship groundings or to restore reefs that have lost corals because of disease or coral bleaching. This is different from relocating an entire coral reef.
Fragments or colonies of some coral species, especially the branching staghorn coral, have successfully been grown in nearshore nurseries and transplanted to offshore reefs. However, these individual colony fragments or whole corals are measured in terms of centimeters, and are not comparable to the overall structure of a reef that is kilometers in size.
While coral reef restoration holds great promise, its focus is on adding living corals to existing coral reef framework, not starting from scratch to build entirely new coral reefs. Transplanting corals also requires, at the least, ocean conditions that are conducive to growth and survival.
And corals grow very slowly. Boulder corals grow less than 1 centimeter a year (almost four-tenths of an inch) and even the fastest growers, branching staghorn corals, may annually extend just 6 centimeters (2.4 inches) or more, but only if conditions are ideal.
Conditions have not been ideal throughout most of the Caribbean for decades. And reefs themselves grow even more slowly than individual corals. A large reef structure is typically thousands of years old.
An example of coral reef relocation that is cited by proponents of the George Town Harbor pier development project is work that was conducted in 2009, in Falmouth, Jamaica. As proposed for George Town, an area was dredged to make way for a new pier. As part of the mitigation plan, more than 140,000 individual corals were relocated. This has been repeatedly touted as an example of successful coral reef relocation, even though it was not the relocation of a reef, but individual coral colonies.
Furthermore, high mortality of the corals was an issue from the start. That is, after transplanting so many corals, few actually survived to grow and thrive in good condition at their new location. This is not even a good example of successful coral transplantation, by any standards, desp