''Salmo farioides'', commonly known as the West Balkan trout, the Adriatic brown trout, or the Balkan brook trout, is a species of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

found in the

Balkans The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...

, including Albania, Croatia, North Macedonia, among others. It is an important fish in numerous rivers and lakes throughout the region. Identification of ''Salmo farioides'' is difficult due to the high degree of

endemism Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

in the western Adriatic and Mediterranean area, particularly among

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

species, and because of high

phenotypic In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

diversity among trout populations specifically.

Description

''Salmo farioides'' is characterized by large red spots, which are sometimes surrounded by whiteish areas, along the flanks and faint vertical bands that are residuals of parr marks. Among mature individuals, females and males are roughly the same length and weight (36 mm and 458 g, respectively), based on measurements from a population sampled from the

Morača River The Morača ( sr-cyrl, Морача, ) is a major river in Montenegro that originates in the northern region in Kolašin Municipality under Mount Rzača. It meanders southwards for before emptying into Lake Skadar. Its drainage basin covers . ...

Montenegro ) , image_map = Europe-Montenegro.svg , map_caption = , image_map2 = , capital = Podgorica , coordinates = , largest_city = capital , official_languages = M ...

. Sexual maturity is reached after the second summer of life, with spawning occurring between October and through January. Spawning begins when the water temperature is greater than . ''Salmo farioides'' was originally described by

Stanko Karaman Stanko Luka Karaman (8 December 1889 – 17 May 1959) was a Yugoslav biologist of Bosnian Serb ancestry, researcher on amphipod and isopod crustaceans. In 1926 he founded the Museum of South Serbia (later - Macedonian Museum of Natural History) ...

in 1938; because the entire Karaman fish collection was lost, ''Salmo farioides'' is a

neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

. The species like originates from stock that entered the mountainous area of the western Po drainage in the Pleistocene era. It is hypothesized that ''Salmo farioides'' colonized the upper part of the Apennine slopes into the Po drainage and eventually reached the lower part of the river, moving towards the Adriatic during the

Würm glaciation The Würm glaciation or Würm stage (german: Würm-Kaltzeit or ''Würm-Glazial'', colloquially often also ''Würmeiszeit'' or ''Würmzeit''; cf. ice age), usually referred to in the literature as the Würm (often spelled "Wurm"), was the last g ...

, where it would have entered the

Neretva River The Neretva ( sr-cyrl, Неретва, ), also known as Narenta, is one of the largest rivers of the eastern part of the Adriatic basin. Four HE power-plants with large dams (higher than 150,5 metres) provide flood protection, power and water s ...

. ''Salmo farioides'' feeds on mainly bottom-dwelling invertebrates and is found in small, flow-flowing streams. However the microhabitat of ''Salmo farioides'' varies by size of the individual: large fish select deeper microhabitats with slower water speeds, whereas small and medium fish prefer medium-depth microhabitats with slightly faster speeds.

Ecology

''Salmo farioides'' serves as a

bioindicator A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...

of the quality in upland rivers where it dominates cold-water streams and is at the top of the

trophic pyramid An ecological pyramid (also trophic pyramid, Eltonian pyramid, energy pyramid, or sometimes food pyramid) is a graphical representation designed to show the biomass or bioproductivity at each trophic level in a given ecosystem. A ''pyramid of ...

. It is considered as a vulnerable species based on a state-wide threat assessment as a result of climate change and increasing water temperatures in their habitats, as well as overfishing due to

recreational fishing Recreational fishing, also called sport fishing or game fishing, is fishing for leisure, exercise or competition. It can be contrasted with commercial fishing, which is professional fishing for profit; or subsistence fishing, which is fishing ...

. Hydrological modeling suggests that, based on pessimistic projections about the CO₂ concentrations by the end of the century, suitable habitat for ''Salmo farioides'' will substantially decrease. ''Salmo farioides'' is found in

Mavrovo National Park The Mavrovo National Park ( mk, Национален парк Маврово) is the largest of the four national parks of North Macedonia. Located in the west of the country, it spreads over an area of about and is characterized by deep canyons ...

in North Macedonia where part of its habitat would have been damaged by the

Boškov Most Hydro Power Plant Boškov Most Hydro Power Plant, referred to as Boškov Most HPP, is a derivation plant planned to be built in Mala Reka valley, in the southernmost part of the Mavrovo National Park, in North Macedonia. It will have a total capacity of 71,5 MW. Co ...

; as a result of the habitat destruction, international funding was pulled from the project.

References

Notes

{{Taxonbar, from=Q310782 farioides Taxa described in 1938 Endemic fish of the Neretva basin