Gas-filled organ that contributes to the ability of a fish to control its buoyancy
"Air bladder" redirects here. For the special effects technique, see Air bladder effect.
The swim bladder of a rudd
Internal positioning of the swim bladder of a bleak S: anterior, S': posterior portion of the air bladder œ: œsophagus; l: air passage of the air bladder
The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous fish[1]) to control their buoyancy, and thus to stay at their current water depth without having to expend energy in swimming.[2] Also, the dorsal position of the swim bladder means that the expansion of the bladder moves the center of mass downwards, allowing it to act as a stabilizing agent in some species. Additionally, the swim bladder functions as a resonating chamber, to produce or receive sound.
The swim bladder is evolutionarily homologous to the lungs of tetrapods and lungfish. Charles Darwin remarked upon this in On the Origin of Species.[3] Darwin reasoned that the lung in air-breathing vertebrates had derived from a more primitive swim bladder as a specialized form of enteral respiration.
In the embryonic stages, some species, such as redlip blenny,[4] have lost the swim bladder again, mostly bottom dwellers like the weather fish. Other fish—like the opah and the pomfret—use their pectoral fins to swim and balance the weight of the head to keep a horizontal position. The normally bottom dwelling sea robin can use their pectoral fins to produce lift while swimming.
The gas/tissue interface at the swim bladder produces a strong reflection of sound, which is used in sonar equipment to find fish.
Cartilaginous fish, such as sharks and rays, do not have swim bladders. Some of them can control their depth only by swimming (using dynamic lift); others store fats or oils with density less than that of seawater to produce a neutral or near neutral buoyancy, which does not change with depth.
^"More on Morphology". www.ucmp.berkeley.edu.
^"Fish". Microsoft Encarta Encyclopedia Deluxe 1999. Microsoft. 1999.
^Darwin, Charles (1859) Origin of Species Page 190, reprinted 1872 by D. Appleton.
^Nursall, J. R. (1989). "Buoyancy is provided by lipids of larval redlip blennies, Ophioblennius atlanticus". Copeia. 1989 (3): 614–621. doi:10.2307/1445488. JSTOR 1445488.
The swimbladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous...
The bladder is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In placental mammals, urine...
a cloaca into which the urinary and genital passages open, but not a swimbladder. Cartilaginous fish produce a small number of large yolky eggs. Some...
varying pH, and habitats with low dissolved O 2 content due to their swimbladders, which they use primarily to breathe. They can also rise to the surface...
and ensuring proper filtration. SwimBladder Disease refers to a collection of issues affecting a fish's swimbladder, the organ responsible for buoyancy...
The Weberian apparatus is an anatomical structure that connects the swimbladder to the auditory system in fishes belonging to the superorder Ostariophysi...
dried swimbladders of fish. The English word origin is from the obsolete Dutch huizenblaas – huizen is a kind of sturgeon, and blaas is a bladder, or German...
distress. Swimbladder disease is a common condition which impairs their ability to maintain buoyancy. This condition is associated with the swimbladder, a...
Devonian, the "Age of Fishes". Bony fish, distinguished by the presence of swimbladders and later ossified endoskeletons, emerged as the dominant group of fish...
(9.8 ft) in length have been reported. Unusually, their vascularised swimbladders can function as lungs, and most gars surface periodically to take a...
or higher. Another threat to the totoaba is from human poaching: the swimbladder is a valuable commodity, as it is considered a delicacy in Chinese cuisine;...
Fish with isolated swimbladders are susceptible to barotrauma of ascent when brought to the surface by fishing. The swimbladder is an organ of buoyancy...
the swimbladder. These muscles are called sonic muscle fibres, and run horizontally along the fish's body on both sides around the swimbladder, connected...
from the foregut, the swimbladder in ray-finned fishes derives from a dorsal bud above the foregut. In early forms the swimbladder could still be used...
ventricle, and conus. Perch have a swimbladder that helps control buoyancy or floating within the water, the swimbladder is only found in bony fish. In...
spent air out through the gills. Gar and bowfin have a vascularized swimbladder that functions in the same way. Loaches, trahiras, and many catfish breathe...
US$20,000 for a kilogram of totoaba swim bladders, with some making as much as $116,000 in one day. The swimbladders of the Totoaba macdonaldi are being sold...
facultative air breather and can obtain oxygen from air by sucking it into its swimbladder, which is lined with capillaries like lung tissue. Within Osteoglossinae...
will remain motionless. A fish's swimbladder controls buoyancy by adjusting the amount of gas in the swimbladder, allowing it to achieve neutral buoyancy...
Elasmobranchs lack swimbladders, and maintain buoyancy with oil that they store in their livers. Some deep sea sharks are targeted by fisheries for this...
exceeds that in the swimbladder. At this point, the dissolved oxygen in the arterial capillaries diffuses into the swimbladder via the gas gland. The...
to a point which would kill other fish. Steen, Johan B. (1970). "The SwimBladder as a Hydrostatic Organ". Fish Physiology. Vol. 4. San Diego, California:...
piscis" literally means "bladder of a fish", reflecting the shape's resemblance to the conjoined dual air bladders (swimbladder) found in most fish. In...
a stout peduncle. The pectoral fins are placed low on the sides. The swimbladder is large, allowing for minimal energy expenditure while cruising or remaining...
exceptions, they also have a highly vascularized swimbladder lung that supplements gill respiration. The bladder not only provides buoyancy, but also enables...
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