Golomyanka
Encyclopedia
The golomyankas or Baikal oilfish are two species
of peculiar sculpin
-like fish
es endemic to Lake Baikal
in Russia
.
. The lateral line
system on the head consists of large cavities linked by narrow bony bridges with small external pores. Lack of a swim bladder, high lipid
content and porous bones allow the fish to tolerate varying pressure extremes as it moves through the water column. Over a third of the body weight (38.9%) of C. baicalensis is oil.
, and represent a primary food source for the nerpa seal. They are easily identifiable, and are large enough (at 15-20 centimeters) to be easily seen. Golomyanka are unusual for their habit of moving throughout the entire water column of Lake Baikal without much regard for changes in pressure
, although they can exist only within a very narrow range of temperatures and generally tend to find their ecological niche
at 700–1600 feet. They are considered the world's most abyssal freshwater fish. They are also known for rapidly decomposing
in sunlight, leaving behind fat, oil, and bones.
The biomass
of the golomyanka population is estimated at anywhere from 100 to 150 thousand tons, making it one of the most populous forms of vertebrate
life in Lake Baikal. They are extensively preyed upon by nerpa, for which the golomyanka are the primary food source. Food sources for the golomyanka are fairly varied, including their own young and pelagic crayfish
. Shoaling
behavior is not known for this species, and the females do not lay eggs; rather, they are viviparous, producing a swarm of 2000-3000 larvae when they reach sexual maturity
at two to three years.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of peculiar sculpin
Sculpin
A Sculpin is a fish that belongs to the order Scorpaeniformes, suborder Cottoidei and superfamily Cottoidea, that contains 11 families, 149 genera, and 756 species...
-like fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es endemic to Lake Baikal
Lake Baikal
Lake Baikal is the world's oldest at 30 million years old and deepest lake with an average depth of 744.4 metres.Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the...
in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
.
Description
Golomyankas have a translucent body with no scales. They have long pectoral fins, and although pelvic bones are present, they lack pelvic fins. Golomyankas have a strong lateral lineLateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
system on the head consists of large cavities linked by narrow bony bridges with small external pores. Lack of a swim bladder, high lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
content and porous bones allow the fish to tolerate varying pressure extremes as it moves through the water column. Over a third of the body weight (38.9%) of C. baicalensis is oil.
Biology and ecology
They are the principal ecological competitor to the omulOmul
The omul, Coregonus migratorius, also known as Baikal omul , is a whitefish species of the salmon family endemic to Lake Baikal in Siberia, Russia. It is considered a delicacy and is the object of one of the largest commercial fisheries on Lake Baikal...
, and represent a primary food source for the nerpa seal. They are easily identifiable, and are large enough (at 15-20 centimeters) to be easily seen. Golomyanka are unusual for their habit of moving throughout the entire water column of Lake Baikal without much regard for changes in pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
, although they can exist only within a very narrow range of temperatures and generally tend to find their ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
at 700–1600 feet. They are considered the world's most abyssal freshwater fish. They are also known for rapidly decomposing
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
in sunlight, leaving behind fat, oil, and bones.
The biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
of the golomyanka population is estimated at anywhere from 100 to 150 thousand tons, making it one of the most populous forms of vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
life in Lake Baikal. They are extensively preyed upon by nerpa, for which the golomyanka are the primary food source. Food sources for the golomyanka are fairly varied, including their own young and pelagic crayfish
Crayfish
Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
. Shoaling
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
behavior is not known for this species, and the females do not lay eggs; rather, they are viviparous, producing a swarm of 2000-3000 larvae when they reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at two to three years.