Rhodeus amarus ( Bloch, 1782 )

Artaev, Oleg & Ruchin, Alexander B., 2017, The ichthyofauna of the Moksha River, a tributary of the Volga river basin, Russia, Check List 13 (4), pp. 185-202 : 197

Rhodeus amarus ( Bloch, 1782) , Bitterling.

Cyprinus amarus Bloch 1782: 52 .

Rhodeus amarus — Kottelat and Freyhof 2007: 82.

Material examined. Table 1.

Presence of a sub-terminal mouth, and reduced body size (up to 95 mm SL). It was recorded in all types of rivers, landlocked oxbows, ponds, and storage reservoirs. According to the river enlargement, its occurrence rate increases to reach the maximum of 101–300 km from the source. In other water bodies, this species was most frequently observed in storage reservoirs and landlocked oxbows. Its highest share in catches was recorded in rivers up to 25 km from the source ( Table 3); however, this value is determined by one case when this share reached 69.4% in a polluted river (Atmis River, near the Kevdo- Mel’sitovo village) in slowly flowing water. As for the remaining rivers, this species was not recorded, making this case rather than an exception. At a distance of 25 km from the source, its share in catches amounts to 10.6– 14.4%, while the highest share was observed in ponds and lakes, and amounts to 42.5 and 29.8%, respectively.

Rhynchocypris percnurus ( Pallas, 1814) , Lake Minnow Cyprinus percnurus Pallas 1814: 229 .

Phoxinus percnurus — Reshetnikov et al. 2003a: 300.

Rhynchocypris percnurus — Kottelat and Freyhof 2007: 235.

Material examined. Table 1; Fig. 6, B

Presence of small scales and a pale yellow body color pattern. It was recorded in the northern portion of the Moksha River for the first time in 1978 ( Potapov et al. 1998) in a pond of the Mordovskii nature reserve, although this species has long been observed in the adjacent Tesha River drainage ( Puzanov et al. 1955). Currently, the lake minnow is widespread in the floodplain lakes and ponds along the Moksha River, and middle and lower reaches of the Vad River. The share in the catch in the karst and suffusion lakes, and in the ponds on the previously mentioned areas amounts 91.7–98.1%. As for landlocked oxbows, the share in the catch is considerably lower, 16.1%. This species was also recorded in a few shallow rivers running to the Moksha River with a share in the catch amounting to 5–9.2% (Satis and Ryabka Rivers).

Romanogobio albipinnatus ( Lukasch, 1933) , White- Finned Gudgeon.

Gobio albipinnatus Lukasch 1933: 57 .

Romanogobio albipinnatus — Kottelat and Freyhof 2007: 101.

Material examined. Table 1.

Presence of white dorsal and caudal fins, and 42–43 + 2 lateral line scales. It was observed only in rivers, where it appears in 26–100 km from the source. Its occurrence increases with river enlargement from 5.7 to 61.5%; however, its share in the catch varies insignificantly (4.5– 7.7%). This species is associated to larger rivers ( Artaev and Ruchin 2013, Ruchin et al. 2008).