Jana island is situated about 20 kilometres north-east of Al Jubail Industrial City. A low coral cay with long stretches of sandy beaches, the island is surrounded with a fringing reef which, in places, lies more than 1.5 kms out from the shore. A shallow lagoon, enclosed and protected by the fringing reef, has many bottom-dwelling creatures and scattered coral blocks. Moving seaward from the reef crest, the coral reef has a gentle slope down to a depth of 10m. In most locations this slope continues until the coral growth thins out to a sandy bottom, 15-20 m below the surface. In other places, the transition from the 10 m depth to the sandy bottom takes the form of a steep coral drop-off.

Strictly speaking, the diving conditions near Jana are by no means ideal. Surface water temperatures drop lower than 15°C in winter and may rise over 33°C in summer. This limits the recreational diving season to the period from April to October. In addition, the underwater visibility ranges from a low of 5 m to a high of 20 m, with 10 m as the norm. The visibility is affected by the daily tidal changes and the seasonal plankton blooming can give a diver an eerie feeling of diving in a soup of marine organisms. The salinity, temperature fluctuation, and turbidity in the Gulf limits the number of species that can survive in these adverse conditions. but this is outweighed by the fact that the species that live here benefit from abundant food sources resulting in faster growth rates and larger single species assemblages, compared to other locations.

Most diving trips to Jana depart from Al-Jubail. The boats cruise through Berri oil field and past the eastern tip of Abu Ali Island, reaching Jana in about two hours. Due to the predominant northerly winds, diving usually takes place on the south-side of the fringing reef. Most divers prefer to spend their time in the shallows where the highest concentration of marine life is found. Extending for long distances are flat coral gardens that teem with colourful reef fishes, including several species of butterflyfish and parrot fish. Three different butterflyfish species are common, the Arabian butterflyfish (Chaetodon melapterus), the blackspotted butterflyfish (C. nigropunctatus) and the banner fish (Heniochus acuminatus). Large parrotfishes, some with remoras attached to them, swim idly by, scraping the coral with their fused teeth. They are usually followed by the strange-looking broomtail wrasse or a school of tiny moon wrasse. Meanwhile, the brightly-coloured Picasso triggerfish can be seen feeding on molluscs and burrowing invertebrates in the sand, blowing out the unwanted debris through its gills.

But the most conspicuous reef resident is definitely the Arabian angelfish (Pomacanthus maculosus) with its distinctive yellow spot. Unlike in the Red Sea, this species is so abundant here that it is not surprising to see dozens of them in a single dive. On one occasion, I encountered a school of more than 50 sub-adults cruising in a group, stopping every few metres to feed.

In the 10 m range, the reef is dominated by Acropora table corals that may grow to a size of 3 m. These intricately laced table corals provide a home for many juvenile buttlerflyfishes and damselfishes. In the shade of these living tables live other fish such as menacing-looking moray eels and the common half-spotted coral grouper (Cephalopholis hemistiktos). Not far away, are families of clownfish darting in and out of the tentacles of their anemone hosts.

Toward the eastern part of the fringing reef, one can swim around big coral pinnacles that rise from the bottom to near the surface. Their sides are usually well-lit and hence are full of marine life. Schools of blue sailfin tang, fusiliers and the ever-present sergeant-majors circle the outcrops. Other reef residents come to be manicured by the cleaner wrasse. A close examination of the burrows in the walls reveal tiny colourful blennies and juvenile lobsters.

Divers who descend to the bottom of the reef at 15-20 m are rewarded with sightings of different fish species. In these depths, the light level can be low and the pace is not as fast as in the shallows, but interesting species are abundant. On the bottom, small coral blocks and rubble provide a suitable habitat for several species of lionfish and the venomous scorpionfish. Facing the current, groups of spotted sweetlips hover near the sea-floor, seemingly oblivious to approaching divers. On patrol are emperorfish no doubt searching for exposed or injured sea urchins. Among the commonly observed fish seen here are smalltooth -, long-faced -, and blue-scaled emperorfish.

Even the sandy bottom has some special surprises for the observant diver. Benefiting from an almost perfect camouflage, the bizarre-looking Moses sole is difficult to distinguish from the sand. If forced to move, it swims by undulating its flat body. Another master of camouflage is the marbled electric ray (Torpedo sinuspersici) which is capable of jolting its prey with more than 200 volts of electric shock. Another resident of these depths is the spiny porcupine fish. If threatened, this species will inflate its body into a spherical shape with erect spines, rendering it impossible for a predator to swallow.

For pelagics and other big fish, divers usually focus their attention on the blue water out beyond the cosy protection of the reef-face. There, it is possible to see passing schools of jacks, barracudas, or a rare formation of devilrays. Solitary eagle rays may also be encountered, but they usually flee quickly. However, the ultimate reward has to be a face-to-face encounter with a whale shark. This rare creature, the largest fish on our planet, grows to more than 12 m and is seen surprisingly frequently near Jana. During the summer of 1994, I was lucky to see a whale shark on three different days. Nothing in my diving career comes even close to an adrenaline-pumping five-minute dive with one of these graceful giants.

The importance of Jana as a valuable and unique ecosystem is not limited to its coral reefs. The island is a primary breeding site for several bird species, and a nesting ground for the endangered hawksbill and green turtles. As a result, plans have been prepared by the National Commission for Wildlife Conservation and Development (NCWCD) to include Jana, and other offshore islands in the Jubail Marine Wildlife Sanctuary. Once implemented, restrictions on spearfishing and anchor-use will ensure the preservation of the fragile marine and terrestrial habitats of this fascinating and beautiful Gulf island.