Oka River, stony margin in the Kolomna, Moscow region, Russia

_ place in Biotope Aquarium Design Contest 2019

Volume: 50 L
Dimensions: 40x40x35 cm
List of fishes: Neogobius melanostomus , Amphipoda .
List of plants: Ulothrix zonata
Description of decorations: Stones are silicon, quartz, feldspar, small fragments of red granite, large limestone. The sand is gray and yellow, grains of different sizes up to 1mm. A crumb of all the stones listed, as well as small fragments of shells. Shells of snails and freshwater mussels. Tree branches that grow along a river, such as willow and sea buckthorn. All materials are taken from the Oka River and adapted to simulate the natural environment.
Description of equipment: The aquarium has an internal Tetra Filter Jet 400 (400 l / h). The flow is directed upward so that waves are created on the surface of the water. The AC220V 5W 12 LED lamp is LED.
Water parameters: Water temperature 23 ° C; PH 8.1; PO4 0.25; GH 10. Water parameters is achieved thanks to the scenery taken from the river itself. Light suspension in water due to the circulation of water and the activity of the inhabitants of the aquarium, which corresponds to the natural environment.
Additional info:

INFORMATION ABOUT BIOTOPE

Description of the area surrounding the biotope: The Oka River originates from a spring in the village of Aleksandrovka, Glazunovsky District, Oryol Region, at an altitude of more than 221 m above sea level. It passes along the Central Russian Upland.
At first it flows northward, merges with Orlik in Orel, merges with Upa in the Tula region, merges with Ugra near Kaluga and merges sharply east, and after flowing through Aleksin and Tarusa, it turns north again, then it turns east again near the town of Protvino. Near the city of Kolomna it merges with the Moskva River and further, making a bend 10 km east of Lukhovitsy, flows southeast to Ryazan. In the Ryazan region, due to the hilly areas near the Oka, tortuosity is observed. Near the confluence with the Pronea Oka, making a bend, it turns to the right, and after merging with the Para it flows north again, making a large bend near Kasimov. Moksha flows into the Oka River below the territory of the Yermishinsky District, and the Unzha River flows into the territory of the Kasimovsky District. Then it flows with bends, separating the Vladimir and Nizhny Novgorod regions, where it flows through Murom, Pavlovo, Dzerzhinsk. The river at the end of its journey with a length of almost 1,500 kilometers forms a floodplain 2,500 meters wide and flows into the longest and largest river in Russia: the Volga. The height of the mouth is 64 m above sea level. The river has more than 150 tributaries. The catchment area is 245 thousand km². Sometimes, its width is at least 2.5 km. The length in the Moscow region is 176 kilometers. The shores are mainly sandy and clay, overgrown with pine forests. In the city of Kolomna (Latitude, longitude: 55.0794, 38.7783 Altitude: 143 meters), the coast is rocky, except for the beach. The width of the river is up to 200 meters more often 120-130

Description of the underwater landscape of the biotope: The landscape of the Oka is diverse, due to its large extent. The area of ​​the Oka shown in the biotope aquarium has a sandy bottom covered with stones. The sand is mixed, gray and yellow. Sand grains of different sizes up to 1mm. Under the sand there is silt. Along the coast a large amount of limestone from small stones to blocks of several meters. Silicon, quartz, feldspar and red granite are also present in large numbers. Some of the stones are covered with threadlike algal fouling, which are randomly located along the riverbank. Empty sand shells of snails and a small number of shells of freshwater mussels are often found in the sand between the stones. There are no large snags and tree branches growing along the river. The current carries them to the backwaters, but small fragments of fallen parts, a little submerged in the sand, are sometimes found.

Description of the parameters of the habitat: Water in the Oka has a subtle green hue. Along the coast in the water there is a light suspension from small particles of silt, which is formed from waves. The water temperature at this time of year (summer) ranges from 18 to 23 ° C. In autumn, winter and spring, the water temperature is much lower. The temperature of the water and its indicators were measured personally and I do not use any source. PH 8 – 8.3. PO4 0.25; Gh 10

List of fishes and invertebrates occurring in the nature biotope: The basis of the Oka fish herd are:
bream (Abramis brama),
roach (Rutilus rutilus)
Gustera (Blicca bjoerkna).
The sterlet (Acipenser ruthenus) is rare
Also in the Oka lives:
asp (aspius aspius)
white eye (Abramis sapa)
gold and silver carp (Carassius carassius and carassius auratus gibelio)
tench (tinca tinca)
bitterling (Rhodeus sericeus)
Chekhon (Pelecus cultratus)
rudd (Scardinius erytrophtalmus)
bleak (Alburnus albyrnus)
perch (Perca fluviatilis)
zander (Lucioperca lucioperca)
Bersh (Lucioperca volgensis)
ruff (Acerina cernua)
pike (Esox lucius)
burbot (Lota lota)
catfish (Silurus glanis)
loach (Misgurnus fossilis)
plucking (Cobitis taenia)
char (noemacheilus barbatulus)
The sculpin (Cottus gobio), a representative of the family of sculpin gobies (Cottidae), is hiding under the stones under the stones. In the pool, the Oka appeared by chance and took root. They include the round goby Neogobius melanostomus – a brackish-water species whose initial range covers the Caspian, Azov and Black Seas. One of the possible ways for the round goby to enter the Moscow River, and later the Oka, could be the transfer of clutch laying on the bottoms of ships.
Invertebrates:
Crayfish (Latin: Astacus fluviatilis)
Viviparus viviparus L., Paludina vivipara
Unio pictorum
Dragonfly larvae of the rocker-dragonfly type:
Aeschna grandis, Aeschna cyanea and Aeschna viridls.
and other species.

List of plants found in the nature biotope: The following plants are often found in the Oka River
● Potamogeton lucens
● Potamogeton angustifolius
● Potamogéton críspus
● Stratiótes aloídes
● Ceratophýllum
● núphar lútea
● Hydrocharis
● Lémna
● Scírpus
● Glycéria
● Sagittaria sagittifolia
In the Oka, you can find a number of other less common plants. In some areas of the reservoir, there are no plants at all, as is the case with the area in which this biotope was created.

Threats to the ecology: In the suburbs, the most serious situation is developing on the Oka River, which stretches across the territory of the region. In recent years, the Hydrometeorological Center notes that the Oka has become shallow due to unregulated channel mining of sand, which lasted several decades. Mining accelerates the process of subsidence of the coastline and river bottom. The bottom is changing, somewhere in the middle of the river the same depth may remain, but at the same time the level of the river relative to the coast decreases. The shallowing of the Oka affects the reduction in the population of fish and its other inhabitants.

Sources of information:

1.https://fishingday.org/karta-reki-oka/.

  1. http://www.waterguide.ru/reka-oka.html
  2. https://www.kp.ru/daily/26407/3282437/.
  3. https://ru.wikipedia.org/wiki/Ока
  4. My observations

https://www.youtube.com/channel/UCC_tOXGLEd8xPQc1zw_9saw

  1. https://pandia.ru/text/77/317/58207.php
  2. https://zdesriba.online/rybolovnye-mesta/kakaya-ryba-voditsya-v-oke.html

Comments of the members of the jury of Biotope Aquarium Design Contest 2019