Cover photo: Oligosarcus schindleri, locally known as Platincho or Plateado, is endemic to Cochabamba, Bolivia.
“Without water, native fishes are going to disappear. Not only local extinctions will occur, but regional extinctions are likely. Freshwater depletion not only jeopardizes human communities but also native biodiversity. Rivers and certain lagoons are drying up, yet we don’t know how long this crisis will last,” warns Fernando Carvajal, ictiologist and specialist in freshwater ecosystems in Bolivia. In an interview with Armonía, Carvajal expressed his concern about the world water crisis and its impact on native fishes populations, but also highlighted the importance of identifying Key Biodiversity Areas (KBAs) aimed to fishes and their ecosystems conservation, as well as freshwater provisioning for people.
An interaction relationship between the water crisis and water extraction for human consumption is evident in many regions across Bolivia, says Carvajal.
“Rainwater reduction forces higher water extraction, at least in the Andean Highlands and the inter-Andean dry valleys such as the Rio Grande basin, where important tributary rivers are currently dry, for instance, the Misque River. We knew that these rivers significantly reduce their caudal from time to time while maintaining a minimum flow. I therefore think water crisis consequences are quite drastic (…).In places with little water availability, people try to take as much water as possible to sustain their homes and their economy. Such extraction levels are ultimately detrimental to entire freshwater ecosystems and fishes,” Carvajal pointed out.
Regarding the actions needed for fishes and freshwater ecosystems conservation, Carvajal underlined the pivotal role of environmental education and made a call for urgent measures to prevent the degradation of rivers, lakes and lagoons.
“Not all development-related decisions should be based solely on economic factors, we must conserve our natural heritage, which actually provides us the critical ecosystem services. Taking care of this heritage is similar to protecting an unknown treasure that keeps all the benefits for future generations,” emphasized Carvajal.
Fishes are important conservation targets in Key Biodiversity Areas
The process of designating reserves and conservation areas has traditionally focused on terrestrial elements. Freshwater ecosystems have been used as geographic boundaries instead of conservation elements on their own. Fernando Carvajal pointed out that, although the protection of freshwater environments was implicit, it had never been directly and adequately addressed, as it is proposed in the KBA guidelines.
The KBA standard allows the delineation of areas for freshwater biodiversity considering any water body and their watershed even if it has one single trigger species. “It is a great advance to consider fishes as organisms subject to conservation and to start thinking thoroughly of better criteria and mechanisms for effective conservation,” Carvajal emphasizes.
Carvajal is a researcher at the Limnology and Aquatic Resources Unit of the Universidad Mayor de San Simón in Cochabamba, and has more than 20 years of experience in the field of ichthyology; with all this background, he affirms that fishes are the least known group of fauna among all other vertebrate. This is largely due to the taxonomic complexity of the group and the lack of studies using biological samples from Bolivia.
“Despite the fact that numerous expeditions, most of them led by foreign experts, have been carried out in Bolivia, there are still unexplored areas and poorly studied groups of fishes. Over the last decades, there has been significant progress in the knowledge of fish species in Bolivia, with more than 1,100 species recorded so far. However, the evidence suggests us that fish diversity could be even greater than what is known,” he reveals.
Endemic Species and Threats
About 55 endemic species have been identified in Bolivia so far, a figure expected to increase with future research. However, Carvajal highlights that at least 25% of these endemic species are under some degree of threat mainly due to fishing or the degradation of their habitats due to the reduction of their caudals, water pollution or the introduction of exotic or invasive species.
As an example of an endemic fish we have Oligosarcus schindleri, known as Platincho or Plateado in the upper valleys of Cochabamba. “It is a small scaled fish that only lives in the Angostura Lagoon and in a small lagoon in the town of Vacas. It is known that ancient inhabitants of the region consumed this fish as part of their regular diet. Today the Platincho continues to be part of the diet of local communities, therefore, contributing to the food security of the people. However, this fish is experiencing a rapid decline,” says the biologist.
The Platincho faces serious threats, including: the pollution of the lagoons where it lives, the ecological competition with introduced species, and selective fishing in favor of introduced species.
The Platincho is not only part of Cochabamba’s biodiversity and natural heritage, but also a potential resource for tackling malnutrition issues in the region. Conserving the Platincho may constitute a fundamental step to ensure the sustainability of freshwater ecosystems and to improve the wellbeing of local communities.
“Because the Platincho is a food resource for local human populations, but also an endemic species, immediate and effective measures for its management and conservation are urgently needed, for instance reproduction in captivity. It is a fish that is eaten as a whole, which is better than eating only a filet, for instance in terms of nutrient intake for children. In areas with malnutrition problems, such as Vacas, the Platincho may be an important alternative to supply nutrients and give a better quality of life to some people. For me, this is an iconic fish and although it is still unknown in Cochabamba, we hope to make it more visible, highlighting the importance of conserving this type of resource as something of our own,” recommends Carvajal.
Photo: Biologist Fernando Carvajal studying fish in a lagoon in Cochabamba, Bolivia.