Wakatobi’s House Reef has earned a reputation as one of the world’s finest shore dives. This expansive coral garden, which lies just a short swim from the beach, stretches for more than three miles, and offers untold hours of diving and snorkeling adventures. But there’s another dimension to this site that should not be missed, and it lies even closer to shore.
Just off the beach, stretching from the low tide line to the edge of the reef lies a swatch of greenery. This is the realm of the seagrasses, and though at first glance it may look like nothing more that a patch of uncut grass on your front lawn, or ‘seaweed'. It is actually a distinct and fascinating ecosystem filled with a wide range of creatures awaiting discovery.
A different kind of grass
While it’s generally accepted that life came from the ocean and moved onto the land, seagrasses apparently took a U-turn at some point. Starting some 100 million years ago, grasses growing on land began to adapt to salt water, and expanded into coastal shallows. Today, the 60-something species of seagrass found around the world still have more in common with their terrestrial cousins like algae and other marine vegetation. Like land grasses, they depend on sunlight to feed themselves through photosynthesis, and put down roots that draw nutrients from the ground rather than the surrounding water. They are true flowering plants, releasing pollen and seeds that drift with the currents. The one feature that was lost in the migration back into the sea was the need for a thick stalk to counteract the forces of gravity, as sea grass blades are near neutral in buoyancy. The blades’ ability to go with the flow creates the mesmerizing undulations we often encounter when swimming over a seagrass meadow.
Seagrasses need abundant sunlight and a sea floor soft enough to put down roots, which is why in places such as Wakatobi, you’ll find them growing only on the shallow, sedimentary flats between shore and reef. Here, they often form vast meadows that stretch from the low tide line to the hard substrate marking the beginnings of the reef, or into water depths down to 3m-4m. All too often, snorkellers and divers overlook these grass beds as they fin their way out to the reef. Those in the know, however, will pay more attention to that band of grass between shore and reef, because these meadows form a rich and diverse ecosystem, every bit as important to Wakatobi’s marine ecosystem as the area’s coastal mangrove forests and coral reefs.
Near shore nursery
A seagrass meadow is much more than just a stand of underwater weeds. These plants form the cornerstone of a rich ecosystem that provides food and shelter for a variety of aquatic flora and fauna. The sea grass meadows of Wakatobi create a diverse food web in several different ways. Some animals such as green sea turtles, which are often seen in the shallows around the resort, feed directly on the living leaves. But even when not eaten outright, sea grass leaves benefit the ecosystem. Many of the nutrients absorbed from the sea floor are released into the water column, where they are become available to small filter feeders. The seagrasses also support additional secondary plant life including numerous species of algae, bacteria and plankton that either grow directly on the living plants or take nutrition from the dead and decaying leaves that fall to the sea floor. In addition, when living or dead seagrass blades are carried away by currents, they feed creatures in ecosystems ranging from the reef and open water to the deep sea floor.
Living leaves also create a forest-like canopy that provides cover for small organisms such as juvenile fish and a range of invertebrates. Their presences in turn draws a range of predators. And when the grass beds are closely associated with reefs, as in the case on our House Reef, they become important nurseries for many reef-dwelling species. Scientific studies have identified more than 180 species of fish that either call Wakatobi’s grass beds home, or visit on a regular basis. Add in the several thousand invertebrate animals that are likely to be found here, and you have a prime hunting ground for critter spotting.
The best time for a visit to Wakatobi’s seagrass beds is at or near high tide. This not only assures ample depths within the lagoon to perform fin kicks without silting or damaging the grasses, it is also the time when the majority of transient species move in from the reef. Your first spotting will probably be a green sea turtle, as generations of these aquatic reptiles hatch on the beach at Wakatobi Resort; over the years the resort has been a sanctuary for turtles to live and breed. You’ll also see fish flitting about as well, like silver biddys and thumbprint emperor fish, along with several varieties of colourfully-hued rabbitfish.
Though sightings are not guaranteed, there’s a better than average chance you’ll encounter cuttlefish or squid, either patrolling singly or in roving packs, their bodies’ pulsing in mesmerizing displays. Look closer among the grasses and you may sight a juvenile eel slithering among the stalks, or discover a young blue-spotted stingray hovering close to the bottom. There are octopus lurking in the meadows as well, but it can take a keen eye to discover these masters of camouflage. Zoom in again and you’ll find a whole new level of life, with shrimp and crabs moving about. Take a closer look at what at first may seem like a random bit of debris and you could find yourself face-to-snout with a pipefish or seahorse. The list goes on, and sightings are limited only by your patience, and the amount of time you devote to exploring this transition zone between beach and reef.
The next time you visit Wakatobi Resort, make sure to spend some time in the shallows, discovering yet another dimension to one of the world’s richest marine ecosystems.
Informative and interesting, plus beautiful pictures!