Reed-covered bank of the Yegurechka channel in the Don River Delta, Russia

_st place in Biotope Aquarium Design Contest 2022

Volume of aquarium: 363 L

Dimensions of aquarium: 120*55*55

List of fishes: Pseudorasbora parva, Alburnus alburnus, Leucaspius delineates, Carassius gibelio, Rhodeus amarus, Rhithropanopeus harrisii

List of plants: Cerstophyllum demersum, Vallisneria spiralis, Lemna minor, Phragmítes communis.

Description of Decorations and Substrate: The soil of the aquarium is laid in layers (volcanic lava, zeolite, quartz sand 1 mm, quartz sand 0.3-0.5 mm) with a large slope (the slope is protected from slipping by a plastic grate) and reaches a level of 35 cm at the rear window.

The bottom is strewn with whole and crushed shells of mollusks, both gastropods and bivalves.

As an imitation of sunken snags, oak, poplar, and willow wood (including small roots) was used. These are trees that grow on the shores of a real biotope.

Part of the reed is alive, part is dry, treated with boiling water and replaced as it rots.

The background was made using a dry diorama outside in a special box with separate lighting. It contains snags and dry reeds.

Description of Equipment: WhiteSun 250F Long+ luminaire, Eheim Classic 1500XL filter with Seachem Matrix and Eheim Substrat Pro media, lily Pipe used to reduce turbulence, SCHEGO WS2 compressor.

The cover glass protects from jumping out.

Water changes once a week, 30%.

Water Parameters: Temperature 22 C, pH 8.2, gH 18-25, depending on the season, tds 625.

Additional Info: The fish was caught during the cold season (November) and underwent a slow acclimatization to warm conditions. With active aeration and a temperature of 22 degrees, she does not show any ailments and even successfully recovers from damage by the nets with which she was caught by local fishermen.

The same can be said about Phragmítes communis, which went into wintering, in the aquarium it started to grow slowly but surely.

Aquarium video:

Description of the Area Surrounding the Biotope: The Don Delta is the second largest delta off the coast of the Sea of ​​Azov. It is located at the mouth of the Don River, within the Rostov Region of the Russian Federation.

The climate is temperate continental, close to subtropical.

There are a large number of girls, eriks, lakes, fish ponds. Large areas are occupied by reed beds. Here, many species of fish breed, hibernate and spawning are migratory fish – beluga, sturgeon, stellate sturgeon. This area is located on the main flyway of many birds. Among the plants and animals found, many are valuable to the population, rare and endangered species.

On this territory there is a reserved Donskoy forbidden fish space.

The bottom is formed by light fine light sands and is often strewn with fine crumbs from crushed shells of mollusks.

In recent years, in connection with the salinization of the water of the Taganrog Bay, great changes have occurred in biocenoses, brackish-water organisms from the central regions of the Sea of ​​Azov began to appear here.

Description of the Underwater Landscape of the Biotope: As a model for decoration, the reed-covered bank of one of the channels of the Don Delta, Erik Egurechka (47°10’30.9″N 39°15’07.2″E), was taken. Along its banks there are willows, poplars, oaks, mulberries. Their branches fall into the water, together with the reeds, creating an environment in the water where small fish find food – Pseudorasbora parva, Rhodeus amarus, freshwater needle fish and many crustaceans. Pelagic fish, such as Alburnus alburnus, also prefer to stay on sandy spaces in front of snags and reed beds in order to hide in case of danger. Here you can also find aquatic vegetation, which is poor in the rest of the delta. The sandy bottom is densely covered with shells of dead molluscs, which are carried by the current.

Description of the Habitat Parameters: General mineralization 2.6 g/l, salinity 0.80 ppm, temperature in summer 24-25°C, with warming of the coastal zone up to 28°C, in winter – 2-4°C, pH 8. Transparency depends on the season and winds, in this in the biotope it is larger (up to 50 cm on average) than in the rest of the delta (on average 20-30 cm).

List of Fishes and Invertebrates Occurring in the Nature Biotope: Pseudorasbora parva, Alburnus alburnus, Leucaspius delineates, Carassius gibelio, Blicca bjoerkna, Rhodeus amarus, Rutilus rutilus, Neogobius syrman, Knipowitschia longecaudata, Syngnathus nigrolineatus.

List of Plants Found in the Nature Biotope: Lemna minor, Cerstophyllum demersum, Vallisneria spiralis, Phragmítes communis.

Threats to the Ecology of the Biotope: When it flows into the bay, the Don branches into many branches. Some have completely died, others are dying out in recent years. The current deposits sand deposits at the entrance to the river, as a result of which the delta takes away from the sea about 8 m per year. Before the construction of the Tsimlyansk dam, spring currents eroded these sediments and carried them out to sea. Now silt-sand “plugs” grow faster in the necks and stop the access of flowing waters. Silt settles in the channel, clogs springs, destroys plankton, and massive fish kills occur.

The second problem is the ever-increasing proportion of introduced hydrobionts, which are crowding out the local fauna. This is also reflected in the work, with the help of the active Pseudorasbora parva, which is increasing its presence, and the crab Rhithropanopeus harrisii, which has been actively developing the delta for the last ten years.

Sources of Information:
Startsev A.V., Korchunov A.A., Rabazanov N.I. Ecology and distribution of the Amur grouse Pseudorasbora parva (Temminck et Schlegel, 1846), as an object of biological invasion in the delta and estuarine coast of the Don // South of Russia: ecology, development. 2019. V.14, N3. C.6-16. DOI: 10.18470/1992-1098-2019-3-616

Don Fish Reserve (G. D. Kuchin, V. F. Tsapkov), collection “Nature of the Don Karya”, Rostov Book Publishing House, 1978, comp. Scientific Editor Corresponding Member of the USSR Academy of Sciences Yu. A. Zhdanov

A. R. Boltachev1, Ph.D. biol. sciences, head. Dept., E. P. Karpova1, Ph.D. s., A. V. Startsev, Ph.D. biol. Sciences, p. n. S., O. V. Stepanyan, Ph.D. biol. sciences, deputy dir. Marine Biological Journal
2017, Volume 2, No. 3, p. 3–11

Earth Sciences, 2021, vol. 499, no. 2, pp. 193-202. Hydrochemical composition of water on the coast and fore-delta of the Don in low water conditions (XX–XXI centuries) Academician G. G. Matishov 1, 2, K. S. Grigorenko 1, * 1 Southern Scientific Center of the Russian Academy of Sciences Rostov-on-Don, Russia .

Yatsuta K.Z. ‘Nature of the Rostov Region’ – Rostov-on-Don: Rostov Regional Publishing House, 1940 – p.310 (Section on hydrofauna and flora)

River trip video