CR

Least Silverside

Chirostoma charari

Declining

Overview

Chirostoma charari, the least silverside, is a species of neotropical silverside endemic to Mexico. This species has only been found in a spring in the Lake Cuitzeo basin on the Mesa Central of the Mexican Plateau. It has a longer head and jaw, as well as larger teeth and eyes than other Chirostoma species. Its status is rated as Critically Endangered by the IUCN, and may possibly be extinct.

Chirostoma charari faces severe threats from water extraction and diversion that has dramatically reduced water levels in its native lake system. The species is also threatened by introduced exotic fish species that compete for resources and prey on juveniles. Pollution from agricultural runoff and urban development has degraded water quality, while the small, restricted population makes the species extremely vulnerable to any environmental changes or catastrophic events.

Threat summary

Habitat

This endemic silverside fish inhabits the shallow, alkaline waters of Lake Chapala and associated water bodies in the Mexican highlands. It prefers areas with moderate vegetation cover and clean, well-oxygenated water typical of high-altitude lake ecosystems.

Rocky areas· major

Frequently asked questions

Why is Least Silverside classified as Critically Endangered?
Least Silverside is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Chirostoma charari faces severe threats from water extraction and diversion that has dramatically reduced water levels in its native lake system. The species is also threatened by introduced exotic fish species that compete for resources and prey on juveniles. Pollution from agricultural runoff and urban development has degraded water quality, while the small, restricted population makes the species extremely vulnerable to any environmental changes or catastrophic events.
Where does Least Silverside live?
Least Silverside occurs in Mexico. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Least Silverside?
The main threats to Least Silverside are 1.1, 2.1, 5.3, and 7.3. The full IUCN-classified threat record for this species is detailed on the species page.

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