Our traveller uncovers an effort to rebuild a shallow water ecosystem in the Dutch Antilles.

Marijke Wilhelmus is a freelance web designer whose love of marine life spurred her to go on a yearlong trek around the world to discover examples of sustainable living and preservation projects in remote areas above and below the surface of the ocean. Seed asked Marijke to document her travels by sending regular dispatches chronicling the different characters she meets and the innovative and practical ways of life she witnesses.

(Click on a thumbnail below to view a larger picture)

Bari Reef, Bonaire, Dutch Antilles

I’ve done over 400 dives all over the world, including Hawaii, the outer islands of Fiji, the Cook Islands and Scotland, but I have never seen so many different types of fish or been able to observe their natural behaviors as closely as on Bari Reef.

My senses were overwhelmed when I reached the reef—just 100 meters away from shore—with the beauty and diversity of the fish, which didn’t swim away as I approached. Soon, I found myself surrounded by a large school of shimmering, silver-sided baitfish, moving in unison. I noticed spotted cleaner shrimps in giant anemones, several spotted scorpion fish and peacock flounders, which are masters of camouflage. I also observed lots of juvenile aquatic life like the French angelfish, several species of butterfly fish and an octopus. 

diversreefballslide.jpg Divers place one of the reef balls between the shore at Bonaire and Bari Reef.

After all that, I was not surprised to hear that Bari Reef is the number one dive site for species diversity in the entire Atlantic Ocean. However, the 20-meter path you swim from the reef back to shore has the appearance of a desert. 

It was not always like that. 

The storm surge from Hurricane Lenny in 1999 completely plundered the shallow terraces, damaging the shallow water species, including hard corals like elkhorn and staghorn coral. On top of that, so much sand was deposited from Klein Bonaire, the small island about 2 kilometers away, that the corals were smothered and could not recover.

schoolmasterslide.jpg A schoolmaster lurks within a reef ball.

To help speed up the regeneration of this coral—a process that, if left to nature, would easily span a human lifetime—in January 2006 the Sand Dollar Resort placed 12 600lb. reef balls in the shallow waters between Bari Reef and the shore as part of a pilot project with the Bonaire Marine Park. The goals are to encourage fish and coral to return to the habitat.

The 3-foot high structures, which resemble upside down tea cups, are made of a special mixture of concrete with lower acidity levels than normal cement, thereby stimulating early marine assimilation and growth. The concrete has been mixed with dead milled coral, which encourages the adhesion of new coral polyps. Each reef ball also has about eight to 13 holes on its surface so that fish can swim through it or loiter in the ball. 

smallmouthslide.jpg A school of smallmouth grunts at Bari Reef.

Jerry Ligon, staff naturalist at Bonaire Dive & Adventure, monitors the reef balls about six times per month. He does not expect coral to settle on the reef balls until they have aged more. Another limiting factor is that coral only reproduce after the full moon in the three summer-to-autumn months of August, September and October. Ligon explained that, before the young polyps can settle on any substrate, a particular type of algae must be present so they can begin their differentiation into a multi-cellular organism, which will then become a proper coral head.

I visited Bari Reef about three months after the balls were placed. It appears a lot of marine life has already begun to inhabit them.

My first encounter was with a single, very aggressive sergeant major damselfish that was guarding the eggs that were laid inside the hollow reef balls. The eggs take about five to seven days to incubate, and the male must stay right on top of the egg mass to ensure that they aren’t eaten by any other hungry creature, such as a shrimp or any of the many species of wrasse. 

I also observed parrotfish, surgeonfish and blue tangs eating away at the algae that had started to grow.  Inside the reef balls I noticed a schoolmaster hiding in the shade. I also saw several juvenile yellowtail damselfish, gorgeous looking, dark blue little fish with iridescent light-blue freckles and yellow tails. I had never seen them before.

I cannot wait to return to the reef in a year to see how much more progress has been made in re-establishing this habitat.

Contact Marijke Wilhelmus here.

Originally published July 31, 2006


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