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What are the characteristics of the species?

• The genus Orestias is one of the most representative of the Peruvian Andes and contains the largest number of fish species for a single genus of the entire Peruvian ichthyofauna recognized to date (38 species).

• Orestias comprises a group of species that varies between 9-22 cm in length. They have a varied diet and eat plankton, aquatic insects and small crustaceans.

• The genus is defined by the absence of ventral fins.

• Among other notable characters that allow rapid discrimination of other genera and between species, is the pattern of their scales and pores in the head.

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Where do we study the species?

The study area corresponds to the headwaters or headwaters of rivers that flow to the Mantaro and Apurímac rivers of the Ucayali river system. The Orestias habitats are located in the plains of the watershed of the Huamanga-Vischongo system, and in the high puna of Apacheta and Huaytará-Rumichaca (Departments of Ayacucho and Huancavelica), between 3,800-4,400 masl (ELUs 6, 8, and 10).

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What questions do we seek to answer with the study?

• What are the species of the genus Orestias present in the area of ​​influence of the gas pipeline?

• What is the abundance, distribution, and population status of the species of the genus Orestias in the area of ​​influence of the pipeline and that other species of fish are in the same habitat?

• What are the eating habits of the Orestias species in the area of ​​influence of the pipeline?

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What general results have we obtained to date?

• Orestias cf agassizii was reported as the species present in the study areas. O. cf agassizii has three morpho types.

• The fish are distributed between 3,800-4,400 meters above sea level and are more frequent in environments where water moves slowly (i.e., lentic environments) than lotic.

• The sizes of the fish registered for Orestias have a normal distribution and the size-weight relationship is allometric; the observed proportion of male-female was 1: 2.

• Analysis of the stomach content indicates that Orestias consumes aquatic and terrestrial insects, filamentous algae and crustaceans of the genus Hyalella.

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Why is the conservation of this species important?

• The list of threatened species of wild fauna of Peru places all species of Orestias in several categories from critically endangered to insufficient data. However, the list does not yet appear among the recognized legal norms.

• The state of knowledge of the Orestias taxonomy in Peru needs to be updated.

• Some species of Orestias are important for human consumption in areas such as the Titicaca Basin in Peru. Outside this region, the consumption of Orestias has not been documented but it is assumed that there is a local subsistence consumption by the Andean people.

• The pattern of distribution observed up to now for Orestias is very spaced, with many areas with gaps due to the absence of ichthyological research. This fact, together with the high degree of endemism and the current threat of extinction recognized for some species of the genus, make Orestias a priority conservation objective.

• The Orestias are strongly affected by introduced species such as trout and therefore it is recommended that it not be introduced in places where Orestias has been reported.