M. C. P. Amorim and R. O. Vasconcelos (2008): Variability in the mating
calls of the Lusitanian toadfish Halobatrachus didactylus: cues for
potential individual recognition. J. Fish Biol. 73(6), 1267-1283.
Abstract: The mating sounds (boatwhistles) of nesting batrachoidid
Halobatrachus didactylus males were recorded in the Tagus Estuary from
piers. Thirteen males with 16 boatwhistles per fish were analysed for 20
acoustic features. All variables showed larger between-male than within-male
variation and differed significantly among individuals. Discriminant
function analyses (DFA) considering seven of these variables assigned
90?100% of boatwhistles to the correct individual, depending on the number
of males and number of sounds per male included in the model. The acoustic
features that consistently best discriminated individuals were the dominant
frequency of the middle tonal segment of the boatwhistle (P2) and dominant
frequency modulation, followed by P2 pulse period, amplitude modulation and
sound duration. These results suggest the possibility of individual
recognition based on acoustic cues.
URL:
http://www3.interscience.wiley.com/journal/121432431/abstract?CRETRY=1&SRETR
Y=0
For reprints please contact Maria Clara Amorim (email:
J. K. Horne (2008): Acoustic ontogeny of a teleost. J. Fish Biol. 73(6),
1444-1463.
Abstract: The influence of growth on the intensity and variability of
acoustic echoes from individuals and groups of a teleosts was quantified
using Donaldson trout (rainbow?steelhead hybrid) Oncorhynchus mykiss. Fish
growth was linear in total length (LT) and quadratic in mass. Dorsal
swimbladder area increased exponentially with LT. Allometric growth ratio
(i.e. k) values of swimbladder length linearly increased with LT. Average
swimbladder volumes occupied 3?6% of fish body volume and increased
exponentially with LT. The aspect angle that resulted in the maximum average
acoustic intensity from the group shifted from 80 to 86° through the
experimental period. Mean echo intensities increased at both 38 and 120 kHz
as mean LT increased. Predicted echo intensities at 38 kHz exceeded that at
120 kHz at LT <150 mm but were less than that predicted at 120 kHz at LT
>280 mm. Generalized additive mixed models using LT, swimbladder angles and
lateral elongation ratios of fish bodies were better predictors of echo
intensities than LT alone.
URL: http://www3.interscience.wiley.com/journal/121432435/abstract
For reprints please contact J. Horne
Kind regards
Sonja
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Dr. Sonja Amoser
Daringergasse 3
1190 Wien (Vienna)
Austria
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