My main research interests have been hearing, sound production
and acoustic communication in fish. Among teleosts, there
exists an astonishing variety of sound-producing and hearing
mechanisms. This has raised the question whether the hearing
specializations found in some groups of teleosts represent
special adaptations to intraspecific acoustic communication.
In this context, I have investigated the ontogeny of hearing
together with the ontogeny of sound production in the croaking
gourami Trichopsis vittata (Wysocki and Ladich, 2001),
temporal resolution abilities (Wysocki and Ladich, 2002) and
the representation of conspecific sounds in the auditory
brainstem of fishes (Wysocki and Ladich, 2003) during my
diploma and doctoral thesis in Vienna (http://homepage.univie.ac.at/friedrich.ladich/).
have become interested in how noise affects fish. Fish are
exposed to an ever increasing amount of anthropogenic noise in
their natural habitats. Considerable noise levels are also found
in fish hatching and -keeping facilities.
The potential impacts on fish can be
manifold. For example masking relevant acoustic signals can
impair intraspecific acoustic communication, as well as the
detection of prey and predators. In addition, increased noise
levels may also lead to stress (a deleterious effect of
noise well documented in humans and other mammals) und thus
affect the health and fitness of fish. To understand some of the
possible noise effects on fish, I have investigated masking (Wysocki
and Ladich, 2005) in three species of teleosts with different
hearing abilities and the effects of intense noise on hearing
thresholds and temporal resolution (Wysocki and Ladich, 2005) in
one major source of anthropogenic noise in the natural environment of fishes. Measurements of noise emissions and comparisons to
audiograms (Amoser et al., 2004) have shown that recreational
shipping (power boat race) can affect their hearing to a
different extent depending on their hearing mechanisms. I have
also found noise-induced stress responses elicited by playbacks
of vessel noise in several freshwater fishes (Wysocki et al.,
I am involved in several research projects
investigating the effects of
anthropogenic sound on fishes with the main interest on hearing
loss and the underlying mechanisms. One project studies the
effects of Low-Frequency Active (LFA) sonar on
hearing of different fish species. Additionally, we are
studying the effects of noise produced in aquaculture and during
fish transport on the
health and hearing of fish.
L.E., Ladich, F. Detection of communication sounds. In: Fish
Communication. Ladich, F., Collin, S.P., Moller, P., Kapoor,
B.G. (eds.). Narosa Publ. House, New Delhi, in press.
Ladich, F., 2005. Hearing in fishes under noise conditions. JARO,
Ladich, F., 2005. Effects of noise exposure on click detection
and the temporal resolution
ability of the goldfish auditory system. Hear. Res. 201, 27–36.
Ladich F., Dittami, J.P., 2004. Noise,
stress, and cortisol secretion in teleost
fishes. Horm. Behav. 46, 125.
Wysocki, L.E., 2003. How does Weberian ossicle extirpation
sensitivity in otophysine fishes? Hear. Res. 182, 119-129.
Ladich, F., 2003. The representation of conspecific sounds in
the auditory brainstem of teleost fishes. J. Exp. Biol. 206,
Ladich, F., 2002b. Can fishes resolve temporal characteristics
of sounds? New insights using
auditory brainstem responses. Hear. Res. 169, 36-46.
Wysocki, L.E., Ladich, F.,
2002a. Ontogeny of hearing and sound production in fishes.
Bioacoustics 12 ,183-185.
Ladich, F., 2001. The ontogenetic development of auditory
sensitivity, vocalization and acoustic communication in the
labyrinth fish Trichopsis vittata. J. Comp. Physiol. A