Freshwater ecosystems represent one of the most vulnerable components of the biosphere, currently undergoing intensive anthropogenic impact. The degradation of these environments is driven by large-scale pollution, hydraulic engineering, excessive water abstraction for irrigation and industrial needs, as well as unsustainable management practices such as poaching and increasing recreational pressure. Notably, the rate of biodiversity loss in inland waters significantly exceeds that of terrestrial and oceanic systems, despite the fact that freshwater bodies serve as a key factor determining the richness of flora and fauna in adjacent territories.
A characteristic example of such ecosystem transformation is the territory of the Altyn-Emel National Park, which encompasses the right bank and the waters of the Ili River, including the Kapchagai Reservoir and several small rivers. The historically established composition of the native ichthyofauna in the Ili basin has undergone fundamental changes due to the construction of the Kapchagai Hydroelectric Power Station and the subsequent transformation of the hydrological regime. Large-scale acclimatization of alien species has led to the complete dominance of invasive forms in the region's largest water bodies, while native fish species have been displaced into isolated accessory water systems.
Native Fish Species
A total of 13 native fish species have been identified within the Altyn-Emel National Park and its adjacent territories; of these, 8 are listed in the Red Data Book of Kazakhstan (marked with an asterisk).
Order Cypriniformes
- Family Cyprinidae:
- Balkhash Minnow* — Rhynchocypris poljakowi
- Common Minnow* — Phoxinus phoxinus
- Semirechye Minnow* — Phoxinus brachyurus
- Balkhash Marinka* — Schizothorax argentatus
- Ili Marinka* — Schizothorax pseudaksaiensis
- Scaly Osman — Diptychus maculatus
- Naked Osman — Gymnodiptychus dybowskii
- Family Nemacheilidae:
- Severtsov’s Loach* — Nemacheilus sewerzowi
- Grey Loach — Triplophysa dorsalis
- Tibetan Loach — Triplophysa stoliczkai
- Spotted Thick-lip Loach — Triplophysa strauchii
- Plain Thick-lip Loach* — Triplophysa labiata
Order Perciformes
- Family Percidae:
- Balkhash Perch* — Perca schrenkii
During recent surveys, native species such as minnows, Balkhash marinka, Ili marinka, scaly osman, Severtsov’s loach, and Balkhash perch were not detected within the national park, despite the presence of suitable habitat conditions. This indicates the high vulnerability of the park's freshwater ecosystem. Endemic species such as the Ili marinka and Balkhash perch are currently facing the threat of total extinction.
Naked Osman — Gymnodiptychus dybowskii
Currently, it is one of the most widespread native species in the water bodies of the Altyn-Emel Park, including the vicinity of Basshi village.
It is distinguished by an almost complete absence of scales (hence the name "naked").
The largest individuals in terms of body length and weight (within the national park) inhabit the upper reaches of the Konyrozen mountain river (Dzhungarian Alatau): here, the fish reach a length of 183 mm at the age of 4–5 years.
Alien Fish Species
Order Cypriniformes
- Family Cyprinidae:
- North Caspian Roach — Rutilus rutilus caspicus
- Common Bream — Abramis brama
- Common Sharpbelly — Hemiculter leucisculus
- Stone Moroko (Topmouth Gudgeon) — Pseudorasbora parva
- Chinese False Gudgeon — Abbottina rivularis
- Rosy Bitterling — Rhodeus ocellatus
- Tench — Tinca tinca
- Prussian Carp (Silver Crucian Carp) — Carassius gibelio
- Common Carp (Sazan) — Cyprinus carpio
- Family Cobitidae:
- Nikolsky's Weather Loach — Misgurnus nikolskyi
Order Siluriformes
- Family Siluridae:
- Wels Catfish — Silurus glanis
Order Beloniformes
- Family Adrianichthyidae:
- Chinese Rice Fish (Medaka) — Oryzias sinensis
Order Perciformes
- Family Percidae:
- Zander (Pike-perch) — Sander lucioperca
- Family Odontobutidae:
- Chinese Perch (Eleotris) — Micropercops cinctus
- Family Gobiidae:
- Chinese Goby — Rhinogobius cheni
Among the alien species, the most undesirable are the stone moroko (topmouth gudgeon), Chinese false gudgeon, Chinese perch (eleotris), and Chinese goby. These species compete with native fish for food, prey on their eggs, and are capable of rapid population outbreaks under favorable conditions.
Biological invasion is one of the key factors disrupting freshwater ecosystems. The danger lies in the fact that stocking water bodies with alien fish species for commercial purposes (such as zander) leads to a situation where the introduced species completely deplete the native ichthyofauna, eventually suffering from a lack of food themselves. Thus, the commercial benefit proves to be short-term, while the negative impact on the ecosystem is irreversible.
