Brachypopomus gauderio is not the only electric knifefish recently described from South America, U.S. researchers John P. Sullivan* and Carl D. Hopkins** have described another member of the genus Brachyhypopomus and given it the name Brachyhypopomus bullocki.

This new species is named in honour of Theodore Holmes Bullock, a renowned neurobiologist who died in 2005. Bullock was a pioneer of the comparative neurobiology of both invertebrates and vertebrates and is credited with the first physiological recordings from an electroreceptor and for championing electric fishes as a model system in neurobiology. The electric organ discharge waveform of Brachyhypopomus bullocki is biphasic, 0.9–1.6 milliseconds in duration, and the pulse rate varies from 20–80 Hz.

Brachyhypopomus bullocki is found throughout the Orinoco Basin in Venezuela and
Colombia. It can also be encountered in the in the Rio Branco drainage of Guyana and the Roraima State of Brazil, as well as in the upper part of Rio Negro near the mouth of Rio Branco.

Brachyhypopomus bullocki appears to prefer clear, shallow, standing water in open savannah, or savannah mixed with stands of Mauritia palm. It has also been collected among plants growing along the banks of small pools fed by streams. In Rio Negro, a specimen was found amongst palm leaf litter near the outlet of a black water stream.

Brachyhypopomus bullocki distinguishes itself from its close relatives by having larger eyes (comparative to the head), a short abdomen, and distally enlarged poorly ossified third and fourth branchiostegal rays.

The paper can be downloaded from Cornell University.

* John P. Sullivan, Department of Ichthyology, The Academy of Natural Sciences, Philadelphia. Email: sullivan@ansp.org

** Carl D. Hopkins, Department of Neurobiology and Behavior, Cornell University, New York. Email: cdh8@cornell.edu

A new cichlid species has been described from the Río Negro and Río Tacuarí basins in the Uruguay River drainage by Uruguay ichthyologists Iván González-Bergonzoni, Marcelo Loureiro and Sebastián Oviedo.

The fish has been given the name Gymnogeophagus tiraparae (picture here) after María Luisa Tirapare, a Guaraní woman who founded the town of San Borja del Yí (no longer existing) close to one of the collecting localities for this fish.

Gymnogeophagus tiraparae is found in larger rivers with clear water over both sandy and rocky bottoms where underwater vegetation is scarce. The fish is decorated with two horizontal series of moderately elongated light blue dots between the dorsal fin spines, and a series of light blue stripes between the soft rays, sometimes merging with the second series of elongated dots. Between the series of dots, the body of the fish displays a red ground colour. On this spotty fish, the caudal fin is also adorned with dots, which are vertically aligned on the distal border. The body has no transversal bands at all. Another important characteristic is how the adipose hump on the head is located deeper than the upper border of the dorsal fin.

The description was published in the most recent issue of the journal Neotropical ichthyology.

González-Bergonzoni, I, M Loureiro and S Oviedo (2009) A new species of Gymnogeophagus from the río Negro and río Tacuarí basins, Uruguay (Teleostei: Perciformes). Neotropical Ichthyology 7, pp. 19–24.

* Guaraní is a group of culturally related indigenous people of South America who speak the Guaraní language. They are chiefly found between the Paraguay River and the Uruguay River.

Wild-caught pets are often recommended against, since the harvest of wild caught specimen may deplete wild populations. In the Brazilian rainforest, the harvesting of popular aquarium species such as cardinal tetras have however helped prevent deforestation and made it possible for local residents to earn a living without resorting to logging, mining, cattle ranching, and slash-and-burn agriculture.

“All this is very counter-intuitive,” says Scott Dowd, an Amazon biologist at the New England Aquarium who has been researching the dark acidic waters of Rio Negro, a major Amazon tributary in Northern Brazil, for the past two decades. “You would think biologists would not want to take fish out of the rainforest. But the fish are the key to miminizing deforestation. The people’s other economic options – timber harvest, cattle ranching and gold mining – are environmental disasters.”
The Rio Negro region has been a major fish exporter for over half a century and 60 percent of local populations rely in this source of income for their sustenance. Since deforestation is known to be detrimental to the survival of financially valuable fish species like the cardinal tetra fish, the Brazilian government has protected the Rio Negro rainforest from logging and burning – at least until now. The situation may be about to change dramatically as more and more aquarium shops switch from wild-caught fish to farm-raised specimens. Wild-caught specimens are used to the dark, soft and highly acidic water conditions of Rio Negro, while farm-raised fish tend to be acclimatized to common tap-water conditions (i.e. clear water that is not very soft or acidic) and therefore easier to keep.

To prevent the market for wild-caught Rio Negro fish from collapsing, Dowd is participating in a “Buy a Fish, Save a Tree” campaign. “The local fisheries look like they are headed for collapse”, Down explains. “But there’s hope that this threat can be addressed. If you ask fish hobbyists if they care about the environment, a very high percentage say they care about it deeply.”

Dowd hopes that the “Buy a Fish, Save a Tree” branding will help Brazilian fish harvesters to benefit from the growing trend of cause labelling, such as Fair Trade and FSC (Forest Stewardship Council).

Another important step in making wild-caught Rio Negro fish a popular alternative to farmed-raised specimens is to adapt them to normal aquarium conditions, and the New England Aquarium is therefore helping local fishermen to efficiently acclimatize wild-caught tetras to a pH-value around 7.0.

Dowd also hope to take advantage of the Internet, by assigning lot numbers to every batch of aquarium fish caught in Rio Negro. “Imagine if you could go online and see a video of the actual fisherman who caught your tropical fish, says Dowd. “I want hobbyists to know directly how their choices can affect people thousands of miles away and how they can make a contribution to saving the rainforest. Things don’t look good, but we can begin to turn all of this around.”