The upper course, which includes the area of the National Park is inhabited by 15 species of fish from 4 rows and 6 families. There are 10 recorded species of amphibians (Amphibia) from rows of Anura (bezrepci) and Caudata (repas), in a wider area of the upper course of the river Una which includes the National Park. With its biology, species that are present in this area are generally associated with wet, marsh and aquatic habitats. Species that can be seen are,
Triturus carnifex (a large newt), Salamandra atra (Black Salamander) and Proteus anguinus (olm).
Among the 15 species of fish that are present in the river Una and its tributaries at the area of the National Park, the most important are:
Among the rare species here we can also find a type under the name of Bullhead (Cottus gobio) as well as Two stripes cyprinid as relatively rare and endangered species. Reduction of water quality and habitats can contribute to reduction of the population of this species. Based on Annex III. of Berne Convention, which includes protected species, it contains 6 species - salmon, grayling, two stripes cyprinid, stream barbel, pomfret and bullhead.
Trout is famous for its red dots and spots on the body.There is usually less red spots that black spots. Some subspecies have round black dots of various size on their back as well as on their hips. Red spots may be in shades - from warmly red to completely bright red color. During spawning colors are more expressed and more beautiful. Trout that lives in shallower waters, where the bottom is covered by gravel, are usually light colored, while those from deeper waters and underwater caves or caves are dark and almost black. Only their spots are warmly red their belly is whitish-gray. Young trout are different in color than the already developed and adult trout. Only after the second year of life, the trout gets real colors that change according to the situation in the water (water level, oxygen, bottom composition, etc). It may happen that in the same river the trout from the upper stream is different from the one in the lower stream.
It is known that trout in minor waters and streams can not grow particulary due to reduced opportunities and conditions. Usually these are the trout up to twenty inches in length. In the larger waters, where the food conditions are outstanding, it can grow up to ten kilos, and even more. The trout lives in mountain streams across Europe - from the far north to the mediterranean coast of Africa. The essential requirements for its life is the amount of oxygen in the water, flow rate and water temperature.
The trout has a larger head with a blunt muzzle and a large mouth with sharp teeth. The fins are firm and rounded and quite wide. Its belly is silvery, yellowish or light gray, and its back and ridge is from lighter to dark green, dark gray or dark brown or to almost blackish color. Hips are usually greenish or yellowish. Its shells are small and nearly round. The trout is an excellent and fast swimmer, and its body is beautiful and built in proportion. The ideal water temperature for brown trout is up to 10 ° C or so, however, it can handle the water of 15-16 ° C. The trout is usually always in one area, and when it moves it is usually because of the lower level ( usually downstream) or because it searches positions for the spawning (upstream), and also because it is in search of food slightly upstream or downstream.
According to the climate conditions it usually spawns from late autumn to late January. Male and female find a proper place that is not too shallow or too deep, on the gravelly bottom of rivers or streams, at the mouth, they dig the ground about twenty inches deep with their heads and tails, and there the female lays eggs which the male immediately fertilizes. On average, the female usually lays about 900 pieces of orange eggs, diameter of 5 mm, which cracks after about two months. It becomes sexually mature after two to three years. Trout is a voracious and very cautious fish. While young, it feeds on insects, worms, larvae, grubs and insects, and later attacks everything it can on the surface and bottom, and even leaps from the water for flies. At that time it already attacks small fish, crabs and a small frog. Trout fishing is particulary interesting because it requires a fair dose of effort, ingenuity and experience. It is known that the hauntig is usually performed in two ways (the rest is poaching). The hunting is usually performed with the artificial fly only with special equipment for the artificial fly or with plastic water ball ("vasserballs") or using a stick for pulling (''spinaching'') and rolls with a small lures, and by using a small spinning butterfly lure. The trout fights very skillfully as soon as it senses that it is caught. It quickly swims against the current, leaps from the water and swims towards the bush or shrub.
Smaller pieces are retained in streams and currents around the falls, and in the depths of large whirls or under rocks and logs, large pieces live. The best time for the fly fishing is from mid-July and again from late August to October. It is known that the best time to caught a trout is on cloudy days or after gentle summer rain. Trout is considered the finest of all the fish from the rivers.
Grayling is one of the smartest and most beautiful freshwater fish. Its body is slender elongated and covered with a firm, relatively tiny scale. Unlike the stream trout it has an unusually large and long, metal-blue dorsal fin with 3-4 rows of large red and purple spots, and a small head, which narrows and makes a tapered tip, with a small barely visible mouth and poorly developed teeth, because of why it is haunted with smaller flies. It is also recognizable by the large eye with a green-yellow iris. The lower fins are ashy, with pale-red and violet dressing on top. The tale fin is copper-red and adipose fin is gray with red dressing. On the sides behind the head there is a smaller or larger number of black spots. From both sides of the body above the belly fins are adorned by a large irregularly shaped red dressing. During the spawning all the colors are more pronounced especially in males. The front of the dorsal fin is higher in males than in females.
Habitat, habits, feeding behavior and diffusion:
Geographical diffusion of grayling is huge and catches the northern and the middle part of the Euroasian continent. It lives in the lower parts of the trout rivers in the zone which actually has its name: grayling zone. Its habitat is very typical and it hardly comes out of it. Grayling lives in larger or smaller flocks where the fish are classified when born. The finest places at the fastest and the deepest sectors, is what they occupy the most, in large gravel pits, in long and regular river flows, in the narrowing and wherever there is food in abundance. Grayling is a cold water fish, and it often lives together with a stream trout, although it each has their individual area. Unlike the trout it likes quieter, less lavish and relatively larger flow. In nature, however, there is no sharp distinction between these two areas, so these two fish live together.
Most of its time the grayling spends at the bottom which they relentlessly search looking for different larvae or nymphs. Grayling is the faster hunter of flies that fall or just touch the water surface while flying. There is also the beauty of the fight between the fisherman and the grayling. Because in a split second, when the fly touches the water, it pops like a lightning from the bottom and grabs it. But, unlike other fish, this one never swallowes the fly immediately, but first tastes it with the sensitive lips and palate, and then, if it doesn't like it, it just spits it out. On the first day of its life it feeds on plankton, while it is in younger stage it consumes the eggs of other fish and various aquatic invertebrates. The largest specimens can even grab the occasional fry. During the periods of massive hatching of insect, grayling gladly comes out to the surface and captures insects that are carried away by current. In strong currents, it can not be found (at least not the larger ones), because they prefer to stay in a silent and deep spills.
For the breeding, grayling requires clean water rich in oxygen. Even because of the least pollution, changes in water level, water temperature or composition of the bottom, it reacts by temporarily and sometimes permanently abandoning of the zone. Grayling is the vernal spawning fish and its onset depends much on the temperature. It generally lasts from April to mid May. In the cold mountain rivers spawning begins later. In our rivers the spawning is performed at a temperature of 6-10°C. When the waters are deep, the day and other conditions favorable, the female will shed eggs in the vicinity of the residence. Eggs are deposited in a deep pit, 50-100cm, and thereby it lays 2000-4000 eggs per kilogram of weight. Once fertilized by the male, the eggs are covered with gravel. Incubation lasts approximately 20-25 days. If the area has no suitable fruiting bodies or the temperature is extremely low, the grayling leaves for the spawning to a nearby streams with warmer water and a convenient bottom. Grayling growth was very rapid. After the first year it is already a few inches long.It reaches sexual maturity in the third year of life for males and fourth for females.
Lifetime, size and weight:
The average life expectancy of grayling is between 5-10 years. During this time it can grow an average of 30 cm to 60 cm, with a weight of 400gr up to 1.5 kg.
Description and structure:
Chub has a strong body, spindle-shaped, adapted to swim also in the waters with the stronger currents. Covered with large scales, marked with black tape. Head, massive and strong, ends with the round snout, above wide dismembered mouth, without a mustache. Tail fin is broad and jagged, and the belly fins are placed vertical to the dorsal fin. Its color varies according to the coloring of the water in which it lives. In general, the abdominal area is white. The fins are gray, except for the pelvic and anal which are orange-red. Because of the dark dorsal and caudal fins, chub is recognized even at large distances.
Habits, habitat, distribution:
Chub is a fish of pure water and high speed flows, that mainly lives in the middle and lower parts of streams, in deep eddies, or in the transitions from the vortex to whirlpool. It belongs to the cyprinid or the carp fish species.
Chub has an extraordinary ability to adapt to various environments, both at the level of reproduction and in the selection of habitat. It is a resident of the streams, fresh but not cold. We find it in the middle of the river, from the bream zone to trout zone. With the exception of small lakes and puddles where it doesn't live because it can not reproduce, it can live in canals, lakes, sandstone, with the condition that all those waters communicate with a river.
In winter, the chub moves to a quiet area close to the water currents, along the hollow shore, in the slow but powerful vortexes, upstream of the hole.
In the spring it always passes over sectors where the water plants grow, along the shallow zones of turbulent flow, and anywhere where insects are numerous. In the summer, it sets in an ambush near the surface, usually in the shade, and is ready to swallow all at once every kind of treat. In autumn, eddies and submerged obstacles allow it to spend the day feeding without greater efforts.
It inhabits almost the entire European continent except for the Scandinavian region, we find it even in the Baltic Sea, which indicates that it is extremely adaptable species. However, chub most rarely inhabits running water with a hard rocky base.
Chub has the ability to register from a large distances even the minimum possibility of food. This great opportunist is interested in everything, has a very diverse nutritional eating habits, eats: molluscs, crustaceans, spawns, tadpoles, various larvae, terrestrial and aquatic insects, herbal and organic debris, moss, algae, fruit that accidentally falls from the tree into the water. It literally eats it all. But the savage appetite doesn't prevent it from being very careful at any time.
Sexual maturity in male occurs in the fourth year, and in female at the age of five. Reproduction takes place between April and June, when water temperature reaches 15 ° C, in shallow zones, rich in oxygen and with the clean bottom. During this period, the male has vivid colors and as a majority of cyprinids it is covered by the so-called wedding spots on the body and head. Females release from 20.000 to 200.000 eggs, which once fertilized, are falling in the gravel. Incubation lasts for a week, and the growth of spawn is fast enough.
As a spawn it lives in flocks and feeds on plankton and aquatic plants, its menu later expanding even on fruit that is located in the coastal zone.