Mudskipper

A fish out of water

Contents: Mudskippers | Development | Goggle Eyes | Amazing Skin | Camouflage | Conflict | Courtship | Extinct? | Movie | Books

At the northern end of the Corniche at Al Khor there used to be a stretch of tidal mud flats, dotted with clumps of mangroves and salt bush along its seaward edge. Until a few years ago the area was home to a small colony of odd little fish called mudskippers.

Copyright: The Mudskipper

Mudskippers

A type of gobie which is able to breathe out of water, mudskippers are endearingly ugly creatures, with bulging eyes on the top of their heads and strongly developed pectoral fins on which they hop around in the vicinity of their burrows. At weekends the Al Khor mudskippers used to regularly receive visits from keen photographers, who would wade out towards them through the glutinous mud, clutching their cameras.

The mudskippers would sit by the entrances of their little burrows in the sides of the shallow creeks meandering across the mud flats, rolling their eyes in a come-hither kind of way and warily watching the approach of their visitors. The very second the photographers got within focusing range the mudskippers would hop nimbly into their holes, leaving a swirl of mud clouding the waters.

From a distance it was possible, through binoculars, to quietly observe the activities of the mudskippers as they kept a close eye on their neighbours, ready to defend any perceived infringement of territory, or calmly skated across the shining surface of the mud with the nonchalant air that befits a fish quite at home out of water. The sound of their Arabic name, boshalanbo, somehow conjures up the jaunty air of these small but fascinating creatures.

Copyright: The Mudskipper

Development

Then came development – the Al Khor Corniche was extended, dredging affected that stretch of coastline, and the mudskippers disappeared, victims of human destruction of their territory. At around the same time, small colonies at Ras al Matbakh at the northern end of Al Khor Bay, and on a stretch of coast near Aladdin's Kingdom, also disappeared for the same reason. These were the only recorded colonies on the long stretch of Arabian Gulf coastline south of the Bay of Kuwait, which is home to a number of species of mudskipper, each adapted to its own particular habitat.

Goggle Eyes

Mudskippers are superbly adapted to their exposed environment. Their large eyes, mounted on the top of their heads, can move independently and give all-round vision. Each eye rolls back alternately into its socket for lubrication. Behind their ears is a cavity containing sea water. As they roll their eyes, pressure on the cavity re oxygenates the water and releases it to lubricate the gills.

A Giant Mudskipper keeps a close eye on what is happening.

Unique among fish species, mudskippers have eyelids. Their eyes have rod receptors above, allowing colour vision and cones below, which give monochrome vision. They usually swim with their heads above water, their huge goggle eyes giving them a 360 degree view of their world.

Amazing Skin

Underwater, mudskippers breathe though their gills like all fishes. Once on land, however, mudskippers can actually breathe air, which they absorb through membranes at the back of their mouths. They can also absorb air through their skin as long as it remains moist. They frequently re-moisten their skin by rolling in puddles and sometimes sit with their tails in water, and this led some early observers to believe that mudskippers breathed through their tails!

On unshaded mud flats at mid-day in the summer months, mudskippers probably approach the extreme among fishes in exposure to solar radiation. All the species have evolved methods of cooling themselves, lying on their sides in shallow pools and stroking their body with a pectoral fin, while supporting themselves on their pelvic fins. The fish have two main periods of activity, in the early morning and in the late afternoon.

Camouflage

The inconspicuous colouring and shape of a mudskipper may help to camouflage it from hungry birds, such as herons, feeding on the mud flats, provided it keeps still. In the Bay of Kuwait one species [Boleopthalmus boddarti] builds conspicuous polygonal territories, each covering about a square metre and surrounded by low mud walls. It is thought that this species was also present in Qatar.

Each fish aggressively defends its territory from interlopers. In the shallow pools of sea water contained by the walls the algae develops on which this species feeds. Several species inhabit the Kuwait mudflats, each adapted to its particular niche on shoreline or in intertidal areas.

Conflict

Copyright: The Mudskipper

Mudskippers employ a great deal of energy in aggressive and defensive behaviour and also in courtship. If an intruder into an individual's territory does not flee when approached, a fight usually follows. Each fish enhances its size by fully erecting its dorsal fin and opening its mouth in a wide gape. The opponents bite and hold onto each other's flanks like terriers, sometimes maintaining their grip for as long as twenty minutes.

Courtship

Courtship takes place between January and May, and males display to attract any female that crosses their territory. Some species develop bright coloration of their dorsal fins, which they spread as they leap and hop in a courtship 'dance'. By flexing their muscular bodies they can catapult themselves up to 60 cm: hence the name 'mudskipper'.

Copyright: The Mudskipper

Although each burrow is normally occupied by a sole male or female, during courtship the displaying male will attempt to entice the female into his burrow where, if he is successful, she will lay eggs which are then fertilised by the male. Usually it is the male which guards the burrow while the eggs develop. Some species maintain an air chamber by gulping mouthfuls of air and releasing it into the chamber. This may play a part in the development of the eggs.

Mudskippers can perch on mangrove roots and branches, climbing with their arm-like pectoral fins. Some have specially adapted pelvic fins which help them grasp the roots as they creep upwards.

Another Extinct Qatar Species?

Fish that can walk on land and climb trees, build walled territories, with lidded eyes that have both colour and black and white vision! Sadly these extraordinary and unique little creatures were overlooked, in the race to develop Qatar, until it was too late. 'Flagship' species like the Arabian oryx were saved, amid much publicity, but no one realised what was happening to an equally remarkable species. A tragedy for this country, as is the loss of any creature. Our world is diminished by their absence.

Is it possible that some might have survived here? Marine biologists won't rule that out entirely, although the last specimens recorded were seen in 1996. However, in other countries which have declared a species extinct new specimens have then been found, so we can but hope.

Mudskippers will not colonise artificially created mangrove plantations, of which there are some 30 around the Qatar coastline. So the only chance is among the extensive natural mangrove forests of Al Khor and Al Thakhira, which have never been fully explored. Maybe, somewhere out there, a few small fishes are still skipping across the mudflats, rolling their eyes and aggressively guarding their homes against all comers.

Mudskippers in the Ganges