First Hydroacoustic Assessment Of Fish Abundance And Distribution In The Shallow Sub-Basin Of Lake Titicaca

Erick Loayza,Instituto De Ecología (Ie)

doi:10.24966/aaf-5523/100034

Abstract

For the last two decades, a rapid eutrophication process impacts Lake Titicaca, the largest tropical freshwater lake in South America and the main highest Great Lake. This is especially notorious in the Bolivian sector of its shallow Lago Menor sub-basin. Lago Menor is deteriorated by the combination of multiple contaminations (domestic, industrial and mining) from untreated wastewater discharged from the urban area of El Alto, indiscriminate overfishing, and climate change. These threats particularly affect the native Andean killifish genus Orestias, the ecology and dynamics of which require in-depth studies with non-invasive techniques.

Highlights

During the last decades, substantial decreases in fish stocks have been evidenced at local and global scales, with freshwater ecosystems being the most endangered [1,2,3]
This study was performed in the framework of the annual fisheries binational monitoring program conducted by IMARPE (Peruvian Sea Institute), coupled with a limnological survey implemented as a collaboration between the French Research Institute for Development (IRD) and the Universidad Mayor de San Andrés (UMSA) in La Paz (Bolivia) [36]
By applying for the first time the hydroacoustic method in Titicaca Lago Menor, we provide a preliminary image of fish distribution

Summary

Introduction

Substantial decreases in fish stocks have been evidenced at local and global scales, with freshwater ecosystems being the most endangered [1,2,3]. For the last two decades, Lake Titicaca has been facing a rapid eutrophication process, most intensively in the shallow Lago Menor sub-basin [6] This deterioration results from mining, domestic and industrial contamination generated by the fast demographic expansion of El Alto city (more than 1.2 million inhabitants), that prior to 1985 was a suburb of La Paz, the Bolivian capital. The rapid increasing human impact was magnified by an intense climate warming due to the combined effects of tropical location (16°S) and altitude, resulting in twice the planet average warming towards 2100 [8,9,10] This pressure threatens most of the vulnerable native Andean killifish genus Orestias [11], that are endemic to Peruvian, Bolivian and Chilean isolated high-altitude lakes [12]

Methods

Results

Conclusion