Mudskippers are fish of the
Family Gobiidae. They are native to the
coastal areas of the
Indian Ocean and
Pacific Ocean, from
Africa to
India to
Asia and
Australia. They are also known as mud-hoppers, climbing fish, kangaroo fish and goggle-eyed mangrove fish. They have acquired their
common names as a consequence of their
amphibian life style. Unlike almost all other fish species, they spend the majority of the time skipping around on the
mud flats near
mangrove stands.
General biology and behaviour
Mudskippers are, on average, from 5 to 30
centimeters in total
length, and have very prominent
eyes, gill covers (
operculae) and
pectoral fins. They have large, rectangular heads with a
blunt snout. Their eyes are located
dorsally on the head, a give the animals excellent vision. They
protrude sufficiently to allow the animal to hide in the water or in the mud, and yet use their eyes as a
periscope. They can keep their eyes from
dessicating by rolling them back into their eye sockets, a movement which also aerates the gills by moving the water or mud around the gill cavity.
Mudskippers use their large pectoral fins and their well developped pectoral muscles to move about on land. Not only are they capable of dragging their bodies along the mud flats, but they can climb small shrubs in search of prey. They are highly territorial, and will bite intruders in order to defend good feeding and breeding habitats. Their pelvic fins are modified in the shape of a suction cup, and they can adhere themselves to a branch or rock, making it very difficult to dislodge when fighthing for territory.
Mudskppers prey upon insects and, for some species, algae. They have been known to feed upon small fish and fish larvae as well. They also scavenge for food, and help keep mud flats and beach clean.
Mudskippers are shallow, warm water species, preferring water temperatures between 30o to 35oC. They live in brackish environments, but will die if confined to either pure salt or freshwater. They, in all cases, prefer living in and on mud to being completely submerged in the water.
These species are able to breathe both through their skin and using their gills. They are able to tolerate severely hypoxic conditions in their burrows, and their eggs are able to tolerate severe reductions in the local oxygen concentration. Their operculae are convex, allowing the animal to suck water and watery-mud into the gill cavity in order to extract the oxygen required for life (think of them as reverse scuba tanks). They can also breathe air with their gills, and may keep their gills moist by wiping them with their pectorl fins. They also have heavily vascularized mouths and pharynxes, allowing them to extract oxygen along those surfaces as well.
Smaller species of mudskippers tend to reproduce near the shoreline, and release their eggs into the water. Medium and larger-sized species tend to reproduce on land, and have evolved two strategies for such reproduction. Those species which nest closer to the water simply build turrets or nests, which fill naturally with water. The males build the nests and then try to attract a female to lay her clutch in his turret. Those that nest further from the water must build burrows in order to have access to the water necessary for the eggs' survival. Since, they often must burrow a considerable distance down, the males have evolved a behaviour to keep the eggs aerated: they gulp air from the surface, descend into the burrow and then release that air into the water containing the eggs.
Conservation status
Mudskippers are under pressure by humans because of their desirability for aquarium enthusiasts and for consumption in
Japan and
Korea. However, they do not appear to be listed by either
CITES or the
IUCN as being
endangered or
threatened.
Taxonomy
Order:
Perciformes
Family:
Gobiidae
Subfamily: Oxudecinae
Tribe: Periophthalmini
Genus,
species:
- Apocryptes bata
- Pseudapocryptes borneensis
- P. elongatus
- Zappa confluentus
- Scartelaos cantoris
- S. gigas
- S. histophorus
- S. tenuis
- Boleophthalmus birdsongi
- B. boddarti
- B. caeruleomaculatus
- B. dussumieri
- B. pectinirostris
- P. freycineti
- P. schlosseri
- P. septemradiatus
- Periophthalmus argentilineatus
- P. barbarus
- P. chrysospilos
- P. gracilis
- P. kalolo
- P. magnuspinnatus
- P. malaccensis
- P. minutus
- P. modestus
- P. novaeguineaensis
- P. novemradiatus
- P. spilotus
- P. waltoni
- P. weberi
Tribe: Oxudercini
Genus,
species:
- Parapocryptes rictuosus
- P. serperaster
- Apocryptodon madurensis
- A. punctatus
- Oxuderces dentatus
- O. wirzi
Some references ...
* http://members.ozemail.com.au/~thebobo/intro.htm
* http://www.aquariacentral.com/fishinfo/brackish/mudskip.htm
* http://www.wwf.org.hk/eng/kids/nature_detective/animals/mudskipper.html
* http://www.vexen.co.uk/holyshit/mudskipper.html
* http://www.szgdocent.org/ff/f-mdskpr.htm