My name is Walter Lechner, and I am a fish-freak … I am an enthusiastic aquarist since primary school days, and I am hooked on water, snorkeling and scuba-diving - this was what made me to study zoology and become a scientist. I am interested in fishes in general and catfishes in particular; my studies on hearing, sound production, communication, systematics, morphology, anatomy, and behaviour aim to contribute to a better understanding of acoustic sceneries and fish communities in fresh- and saltwater habitats. Furthermore, I intend to show the effects of underwater noise pollution on residents from freshwater habitats and thus to emphasize the importance of bioacoustics also for conservation plans. Beside scientific publications, which you can find on ResearchGate, I wrote quite a lot of popular articles for magazines, most of them dealt with species new to aquaristic and by far most of them have been published in German Datz- magazine. I am lucky, because my work includes a lot of field work. I love to go to the field. I do also like my lab work, what means measuring hearing in fishes and making behavioural experiments, aquarium sound recordings, and dissections, and I do the computer work, but I adore field trips to tropical waters. For a former three-years project funded by Austrian Science Fund (FWF) I could go to the Australian Nothern Territory for three times, where Dave Wilson (Aquagreen) brought me to remote habitats of Australian freshwater catfishes (family Plotosidae). We recorded ambient noise, caught fishes and I was able to experience the fantastic Australian wilderness including its dangers by crocs and box jellyfishes. I worked with coral catfishes (Plotosus lineatus) at the Red Sea, supported by the staff of the Ducks Dive Center in El Quesier, Egypt, and I could go to the Amazon for the first two times. This work in the Amazon, at the confluence of Rio Negro and Rio Amazonas, in cooperation with Jansen Zuanon (INPA, Manaus), is continued in my actual project “Bioacoustics of Amazonian fishes”, funded again by the FWF (P 26397). With the help of a lot of students and coworkers from INPA, first of all Tiago Pires, and Claudio Zawadzki (State University of Maringá), we do investigations in acoustic communication, sound production and hearing, as well as in the influence of ambient and anthropogenic noise in the heart of the Amazon system. That’s a dream for a biologist, and a lifetime dream for a fish-freak. In the course of my project I do also study the influence of large dams on the acoustic scenery of rivers. Therefore I work on the Rio Xingu near the new Belo Monte dam, in cooperation with Leandro Sousa from the Campus do Altamira of the Federal University of Pará. And last but not least I cooperate with Tacyana Oliveira  from the State University of Paraíba in  João Pessoa, Pernambucco, in studies in seahorses and estuarine fishes. In Europe Martin Glösmann, Stephan Handschuh, and Stefan Kummer from the VetCore of the University of Veterinary Medicine in Vienna and Tanja Schulz-Mirbach from the Ludwig Maximilians University in Munich are investigating the anatomy of the hearing- and sound-producing structures of some exiting fish species I brought from the Amazon, using µCt- and histology techniques followed by 3d-reconstructions.
email: walter.lechner(at)univie.ac.at phone: +43 1 4277 54430 (office Vienna)          +43 676 7298286 (cellphone Austria, Whatsapp)          +55 928 260 1343 (cellphone Brazil, Amazonas state)            Contact: University of Vienna Department of Cognitive Biology Althanstr. 14 A-1090 Vienna Austria Manaus in the heart of the Amazon, the Rio Negro (blackwater) and the Amazon (whitewater) in the back. At night fishes are especially talkativ. The place Coca Cola comes from: Cachoeira Iracema, a waterfall of a blackwater stream in the Rio Negro drainage; Tiago Pires is placing a hydrophone for recordings. The freshwaters of Australias Northern Territory are quite different to Amazonian waters. Seasonal changes of water-levels are more extrem and swimming and snorkeling is nearly impossible outside of guarded waters in national parks. You will find catfishes of the families Plotosidae (eeltail catfishes) and Ariidae (sea catfishes) in Australian freshwaters. This picture is taken at the Corroboaee Billabong of the Mary River. Coral catfishes (Plotosus lineatus), Mangrove Bay, Red Sea. The estuarines of the coastal rivers of Brazil house a fishfauna totally different from the central Amazon. The whitewaters of the Rio Solimões, the name of the Amazon in Brazil up to it’s confluence with the Rio Negro, contain a huge diversity of fish species. Fishing with dragnets near the muddy banks, for fish-freaks probably some of the coolest stuff they can do. The famous “Encontro das águas”, the watermeeting. The confluence of the whitewaters of the Rio Solimões and the blackwaters of the Rio Negro, forming the Amazonas. Manaus is few kilometers upstream the Rio Negro. INPA runs a field station, a floating house, on the Lago Catalao, a lake-like lagoon connected to the Rio Negro and during highwater season through flooded forests also to the Rio Solimões. Catalao houses innumerable fishes of many different species. Especially below floating meadows the richness of small specimens is amazing. Since Rio Negro and Rio Solimões/Amazonas can be reached by boat shortly, this INPA field station is a perfect base for fieldwork in the main channels of Rio Negro, Amazonas, as well as in the floating meadows and flooded forests surrounding the lake. Small forest streams house fish communities very different to those of the big rivers. Many tiny and cryptic species inhabit the mostly sandy or rocky riverbeds. A young Pirara (Phracto-cephalus hemioliopterus), one of the large predatory catfish species of the neotropics.  The Traíra (Hoplias malabaricus), the most abundand predatory fish species of the Amazon. A Candiru, a “vampire catfish”. Several species inhabit Amazonian whitewaters. Piranhas can produce drumming sounds with their swim bladders. Piranha-caju, red-bellied piranha, Pygocentrus nattereri A Cuiú-Cuiú, Oxydoras niger. This thorny catfish grows up to more than 1 m. They can produce sounds with their swim bladders and with their pectoral fins.
The Piracatinga, Calophysus macropterus, a very special and exceptional pimelodid catfish.