Overview

Twice in 2011 and once in 2013, I was asked to lead research teams to study fish communities of the Kuribrong River, a left-bank (northern) tributary of the Potaro River, part of the Essequibo River drainage in Region 8, Guyana. The overall goal of this field-work was to evaluate the potential environmental impact of a hydroelectric dam that had been proposed for the Kuribrong River at Amaila Falls, which is a major waterfall and rapids complex created by the Kuribrong River's nearly 370 vertical-meter decent from an escarpment of the western Guiana Shield. During initial surveys of the upper Kuribrong River upstream of Amaila Falls in Spring of 2011, four potentially endemic and undescribed fish species were discovered: a new tetra (Characidae: Astyanax sp.), a new South American darter (Crenuchidae: Characidium amaila Lujan et al. 2013), a new Lebiasina sp. (Lebiasinidae) and a new catfish (Heptapteridae: Brachyglanis sp.).

        Each of these species fell under the protection of the strict environmental safeguards of the Inter-American Development Bank, which was considering financing the dam, because the dam could have posed a threat to their critical natural habitat. To test this hypothesis, I led a second survey of the upper Kuribrong River in Fall of 2011 with the objective of sampling portions of its watershed that were outside the direct area of impact from the dam and its reservoir. All but the Characidium sp. were found to be widespread habitat generalists throughout much of the upper Kuribrong River watershed. The Characidium sp. was collected only from shallow, rocky rapids habitats, of which there only appeared to be five clusters in the entire upper Kuribrong River watershed. A third expedition was funded in 2013 to precisely map these mesohabitats and estimate population densities and microhabitat preferences in each. That same year, I published a description of this species as Characidium amaila.

        Ultimately, the Amaila Falls Hydroelectric Project was cancelled because the financial cost would have been too great. Unfortunately, environmental costs continue to be incurred in the Kuribrong River as the road that was built to service the proposed dam is now left open to gold miners, timber harvesters and hunters. Gold mining in the Kuribrong River is especially devastating to fish communities, perhaps much more so than a dam would have been. At the very least, the research that my colleagues and I conducted in the Kuribrong River should provide a baseline for understanding the intact biodiversity of this area, which will be essential for any future conservation efforts. 

        Other vertebrate biologists involved in this research include Brazilian fish biologists Flávio Lima, Tulio Teixeira and Tiago Pessali and herpetologists Brice Noonan and Pedro Bernardo. Voucher specimens collected during this trip are now cataloged at the ROM (field number prefix GUY11 and GUY13) and MZUSP, where they continue to benefit ichthyological research. Published papers that have already benefited from collections and observations made during this trip include the following:

• Lujan, N.K., J. Armbruster, N. Lovejoy, and H. López-Fernández. 2015. Multilocus molecular phylogeny of the Loricariidae (Pisces: Siluriformes) with a focus on subfamily Hypostominae. Molecular Phylogenetics and Evolution 82A:269–288.

• Lujan, N.K., H. Agudelo-Zamora, D.C. Taphorn, P.N. Booth, and H. López-Fernández. 2013. Description of a new, narrowly endemic South American darter (Characiformes: Crenuchidae) from the central Guiana Shield highlands of Guyana. Copeia 2013:454–463.