Mangroves are crucial nurseries. Schools of small fry shift away through the Moorish architecture of arched roots, each school a pale cloud of translucent fish. The palest clouds are hardly there at all, composed of hatchlings no bigger than the smallest mosquito wigglers. These living motes are too small to name. Are they destined for adulthood in a sea grass bed, or coral reef, or open ocean, or right here in the mangroves? Too soon to tell.
And so it goes on Central America’s reef system. Each component of this tripartite world of mangrove, sea grass, and coral reef is itself divided in two: the world above elementally simple, the one below bafflingly complex.
The Mesoamerican Reef system stretches more than 600 miles along the coasts of Mexico, Belize, Guatemala, and Honduras. Its Australian cousin, the Great Barrier Reef, is great indeed at 1,429 miles long—the biggest structure created by living things on this planet. Yet the Mesoamerican Reef, at less than half the length, is in its own way the more remarkable.
The contours of the continental shelf here encouraged the development of an underwater reef platform that begins within a few hundred yards of shore in some places and as much as 20 miles offshore in others. This platform supports a variety of reef types and a profusion of corals unique in the Western Hemisphere. If the Mesoamerican Reef has any advantage over its massive Australian counterpart in the Pacific, it is in this proximity to land and the intimacy of its connection with inshore habitats. Here the provinces of mangrove, sea grass, and coral reef are bound so tightly together by currents, tides, and mutual need that it’s really not possible to tease them apart.
Images and captions courtesy of Brian Skerry and National Geographic. Images are from the October edition of National Geographic magazine.
A whale shark, biggest of fishes, hangs out with small fry off the northern tip of the Yucatán Peninsula.
Mangroves contribute to the system by trapping reef-bound sediment, filtering out pollution, and serving as nursery for many reef fish and invertebrates. The arched roots of mangroves like these form gateways through which multitudes of juveniles swim toward adulthood on the reef.
A Caribbean reef shark samples a Pacific lionfish at Cordelia Banks in Honduras. A few spiny lionfish escaped from an aquarium 20 years ago, and today they’re a plague, preying on the reef’s fish population. Scientists are helping sharks acquire a taste for the invaders by feeding them speared lionfish.
A trumpetfish hangs in the coral gardens of Lighthouse Reef atoll off Belize.
Lighthouse Reef atoll off Belize is one of the most seaward outliers of the Mesoamerican Reef.
Images from the October edition of National Geographic magazine.