ST HELENA | MARINE LIFE
The remote location of St Helena has allowed many marine species to evolve independently of the rest of the world. Some of the endemic species of the island have only been recorded at a handful of dive sites. Not only is seeing such creatures a rare event, but finding one in a location where it has never been seen before would represent a significant discovery. And it is highly likely that there are some critters in the local waters that have never been seen before. Besides these rarities, there are many more familiar species to encounter from whale shark aggregations to schooling wahoo…
One of the most popular sightings among the local divers, the flameback angelfish (Centropyge aurantonotus) is a dark blue/purple colour with a bright orange and yellow dorsal covering. Also known as the Brazilian flameback angelfish, they are distributed from the southern Caribbean to the coast of Brazil - and St Helena, some 2,000 miles away, where they have been spotted at only three locations - Egg Island, Torm's Ledge and Speery Island.
St Helena Butterflyfish
While butterflyfish are fairly common throughout the tropics, the St Helena butterflyfish (Chaetodon sanctahelenae) is endemic to St Helena and Ascension, some 700 miles north. They reach a maximum of 18cm in length but form massive schools, well over 1,000-strong, especially around the shipwrecks, where they provide a bright yellow and white curtain between the diver and the wreck. They are locally known as the 'cunningfish', for their ability to snaffle bait from fish hooks, without being caught themselves.
Also endemic to St Helena and Ascension, this unusual butterflyfish (Prognathodes dichrousis ) is usually found under ledges and inside caves, and like its cousin, the St Helena butterflyfish, is found only around St Helena and Ascension. With its elongated snout, brown frontal area and lower body and its distinctive, white spiky dorsal fin structure, it's not difficult to imagine how it got its name.
Mostly found in the nooks and crannies of shallow water during night dives, Melliss's scorpionfish (Scorpaena mellissii) is found only around St Helena. Like most scorpionfish pecies, the fish has a mottled appearance, in this case varying between light brown and a deep red, with a pattern of lighter colour spots along their sides. And like their tropical relatives, they have venomous dorsal spines which cause very painful stings. They grow to between 20 to 25cm in length.
Another species endemic to St Helena and Ascension, the marmalade razorfish (Xyrichtys blanchardi) would be classed as rare on a worldwide scale, but is very common around St Helena, living around sandy areas in which they will bury themselves if threatened.
Not as brightly coloured as some of their tropical relatives, the strigate parrotfish (Sparisoma strigatum) is often found in groups, feeding communally on the algae which they scrape off the rocks with their beaks. Males have a dull, purply-grey body with black mottled patches. The smaller females have a yellow head with a much darker tail section.
Everybody loves blennies, and Scartella springeri is found only in St Helena. Mostly in shallow water, but also sometimes the tide pools aroound Lot's Wife's ponds. One of three species of Blenniidae found around the island, with the more widely distributed redlip, or horseface, blenny (Ophioblennius atlanticus) – also known locally as the devilfish, due to its propensity to attack intruders with their very sharp canine teeth – and the textile blenny (Entomacrodus textilis), endemic to only St Helena and Ascension, and also found in shallow waters.
The wahoo (Acanthocybium solandri) is found throughout the world and is a common sight around St Helena. They can grow to over 2m in length, and with their elongated silver body and blue-green vertical stripes, combined with ferocious predatory behaviour, they are often mistaken for barracuda.
St Helena White Seabream
A silvery fish, Diplodus sargus helenae is approximately 25cm long at its largest and is common around the island and another fish endemic to St Helena. Usually found in shallow water in small groups, younger fish are often spotted over the sand on night dives.
Rough Toothed Dolphin
Of the three species of dolphin that are found around St Helena, the rough-toothed dolphin (Steno bredanensis) is the least commonly encountered, usually travelling in small groups, sometimes alongside its larger cousin, the bottlenose (Tursiops truncates). The rough-toothed dolphin can grow as large as 3m in length and is so called for the indentations that run along the length of its beak, rather than any particular problems with its teeth.
Pantropical Spotted Dolphin
The pantropical spotted dolphin (Stenella attenuata) is encountered all year round, especially off the north-western shore, protected from the stonger currents to the south and east. They frequently travel in groups of 200-300 individual animals although pods of more than 400 have been recorded. They are often seen playing alongside marine traffic and are known for their agile and acrobatic displays.
Chilean Devil Ray
Mobula tarapanca, commonly named the Chilean devil ray, is frequently spotted by divers around St Helena. Like its larger cousin, the oceanic manta (Mobula birostris), it is a primarily pelagic species but is often spotted feeding and cleaning in coastal waters. With a maximum width of 3.7m, it is smaller than fully grown manta, but is as equally inqusitive and will often make close approaches to dive teams. The dorsal side is a dark green to brown colour with a white and grey patterned underside. It has a short, spineless tail.
Whale sharks (Rhincodon typus) are the largest fish found in the world's oceans but are also known as the 'gentle giants' of the sea. The largest recorded whale shark measured 12.65m in length, although unconfirmed reports suggest they may grow as long as 14m or more, and weigh more than a staggering 21 tonnes. Despite its size, whale sharks are filter feeders, feasting mostly on blooms of microscopic plankton, and occasionally small fish. Whale sharks visit St Helena between December and March every year, with more than 30 different individuals sighted during a single day, although not in the same location. St Helena is the only known location in the world where adult male and female whale sharks congregate in equal numbers, presumably to mate.
For more about St Helena's Whale sharks - click here.
Humpback whales (Megaptera novaeangliae) are seen around St Helena between June and December. Reports suggest that pregnant females arrive in the area to give birth, remaining in the island's waters long enough to feed their solitary calves until they are strong enough to make the journey south towards the Antarctic waters in which they feed, later in the southern summer. They are frequently encountered out at sea during this time, and specialist whale watching trips can be organised. Divers are unlikely to encounter them directly underwater, but they can often be heard singing from further offshore, a special experience for anybody in the water at the time.
Orange Cup Coral
There are a number of species of coral endemic to St Helena, such as the orange cup coral (Balanophyllia helenae) a beautiful, bright, yellowy-orange species whose large polyps are often found under overhangs and around caves. While St Helena does not possess the great fringing coral reefs found in the Indo-pacific region, it's important to remember that there is nowhere else in the world where this vibrantly-coloured coral can be found.
Both green and hawksbill turtles are found around St Helena, probably using it as a brief rest-stop before continuing their journies to their nesting grounds on Ascension, more than 700 miles to the north of St Helena, which has the second-largest recorded nesting site of the green turtle (Chelonia mydas) in the world. There is very little in the way of sandy beaches around St Helena, although unsuccessful nesting attempts have been recorded in the black sand of Sandy Bay on the southern coast of the island.
MARINE LIFE OF ST HELENA | JUDITH BROWN
Much of the information for the critters above was sourced from the most excellent book Marine Life of St Helena by Judith Brown, former head of the Marine Research Division on St Helena and now based on Ascension. The book catalogues much of the wildlife found in the waters around St Helena, especially the endemics, but also contains chapters dedicated to the island's avian residents and also the local shipwrecks. Marine Life of St Helena is available from the publishers, and is on sale on the island.