Full Description

"Disturbance calls were produced when captive U. canosai were startled, chased with a net or grabbed by the tail. Calls were unusual for sciaenids because each pulse consisted of multiple cycles. The number of cycles per pulse and dominant frequency did not change with U. canosai size, but pulse duration and interpulse interval increased. Advertisement calls were recorded from unseen choruses in the field and confirmed with captive individuals in a large tank. Advertisement calls were recorded throughout the known range of the species in Uruguay indicating a continuous belt of spawning populations. Tank recordings of the same individuals permitted explicit comparisons between the two calls. Advertisement call pulses averaged 2·4 more cycles (11·0–8·6) although pulses of both calls were basically similar as were durations and dominant frequencies. Pulse number, however, differed markedly, averaging 13·6 and 3·4 pulses for disturbance and advertisement calls respectively. Furthermore, disturbance calls were produced as a rapid series with an interpulse interval of 26–31 ms whereas advertisement call patterns were less stereotyped and ranged from <100 to 450 ms. Multicycle pulses distinguished U. canosai from other sympatric sciaenids."

"Additionally, passive acoustic monitoring was used to chart the position of calling U. canosai to compare the position of spawning choruses with known distributions (Haimovici & Viera, 1986)."

"Five running-ripe males were recorded while courting females and during disturbance stimuli in the 1000 l tank."

"Advertisement choruses were recorded at sites that match the known distribution of U. canosai in Uruguayan waters (Fig. 1)."

"Individual sound pulses, consisting of multiple cycles, often overlapped and were difficult to distinguish in field recordings (Fig. 2)."

"Disturbance calls, a train of pulses, were evoked by all three stimuli when males were held or swimming freely."

"Individuals emitted one to two bursts, each consisting of a train of four to seven pulses (Fig. 3). Each pulse consisted of a number of cycles (mean ± s.d. = 9·4 ± 2·4, commonly six to 11 but up to 18). Each pulse increased in amplitude for several cycles before gradually decreasing. The pulse duration was 27·3 ± 4·2 ms (range: 19–32 ms), pulse period 22·6 ± 4·3 ms (16–28 ms) and dominant frequency 292·0 ± 19·5 Hz (264–330 Hz). The average pulse period, the sum of pulse duration and interpulse interval would therefore be 49·9 ms. Pulse duration and period increased linearly (P < 0·05), but number of cycles and dominant frequency did not change with LT (Fig. 4). Pulse duration and period levelled off and appeared to remain constant in the largest individuals (>28 cm LT), including those in spawning condition."

"Advertisement calls, a voluntary train of multi-cycle pulses, were recorded from spermiating individuals but not from ripe female U. canosai (n = 5) in the 1000 l tank (Fig. 5). The call was produced by males swimming freely in the experimental tank when orienting towards or chasing females."

"The advertisement call consisted of a series of individual pulses (Fig. 5), the duration, interpulse interval and dominant frequency of pulses values of 31·2 ± 1·8 ms (29–34 ms), 234 ± 138 ms (97–430 ms) and 281·0 ± 19·5 Hz (251–299 Hz), respectively. Individual pulses had a mean of 11·9 ± 3·2 cycles (ranged from 7 to 19 cycles). The greatest amplitude occurred in the fourth cycle in oscillograms, with later cycles often greatly attenuated (Fig. 5)."

"Advertisement and disturbance calls from the same individuals had similar waveforms although advertisement calls had 2·5 additional cycles, respectively, mean ± s.e. 11·9 ± 3·1 to 9·4 ± 2·4 (t4 = 4·707, P < 0·01). Pulse durations were similar (t4 = 0·6470, P > 0·05), 31·2 ± 0·8 and 30·6 ± 0·4 [Fig. 6(b)] as were dominant frequencies (t4 = 0·0840, P > 0·05) 281·8 ± 8·8 and 282·2 ± 7·5 Hz [Fig. 6(d)]. Advertisement calls, however, had fewer pulses (t4 = 8·8110, P < 0·001) than disturbance calls, 3·4 ± 0·5 and 13·6 ± 1·4, respectively [Fig. 6(a)]. Interpulse interval was longer and more variable (t4 = 3·105, P < 0·05) in advertisement calls, 226·6 ± 64·2 and 27·4 ± 0·2 [Fig. 6(c)], respectively. As before, disturbance calls were produced as a rapid series with an interpulse interval of 26–31 ms whereas advertisement call patterns were less stereotyped and ranged from <100 to 450 ms (Fig. 7). Therefore, the calls were made of similar pulses although number of cycles differed and duration and dominant frequency were similar. Advertisement calls, however, had fewer pulses with longer and more variable intervals."

"Similarly, male U. canosai produced disturbance calls when threatened and some characteristics of their calls varied with U. canosai size. Pulse duration and interpulse interval increased although dominant frequency and number of cycles per pulse did not change with U. canosai size."

"In conclusion, U. canosai gather in high-density choruses that contribute to the Uruguayan soundscape on the inner continental shelf between 17 and 40 m, bottom temperatures between 12 and 18_ C and salinity between 29 and 33 (Lorenzo et al., 2011). Choruses are sufficiently dense that individual callers are difficult to distinguish in field recordings, as in other sciaenids (Luczkovich et al., 1999; Lagardère & Mariani, 2006; Borie et al., 2014). Umbrina canosai shares its habitat with C. guatucupa and M. furnieri (Tellechea et al., 2010a; Tellechea & Norbis, 2012). The variation in call variables with Lt and long pulse durations in U. canosai suggest that acoustic variables may enable females to distinguish caller size and differentiate U. canosai sounds from the other two sympatric sciaenids."

Observation Environment Quotes

"Advertisement calls were recorded from unseen choruses in the field and confirmed with captive individuals in a large tank. Advertisement calls were recorded throughout the known range of the species in Uruguay indicating a continuous belt of spawning populations. Tank recordings of the same individuals permitted explicit comparisons between the two calls."

Behaviour Description Quotes

"Disturbance calls were produced when captive U. canosai were startled, chased with a net or grabbed by the tail. Calls were unusual for sciaenids because each pulse consisted of multiple cycles. The number of cycles per pulse and dominant frequency did not change with U. canosai size, but pulse duration and interpulse interval increased. Advertisement calls were recorded from unseen choruses in the field and confirmed with captive individuals in a large tank. Advertisement calls were recorded throughout the known range of the species in Uruguay indicating a continuous belt of spawning populations. Tank recordings of the same individuals permitted explicit comparisons between the two calls. Advertisement call pulses averaged 2·4 more cycles (11·0–8·6) although pulses of both calls were basically similar as were durations and dominant frequencies. Pulse number, however, differed markedly, averaging 13·6 and 3·4 pulses for disturbance and advertisement calls respectively. Furthermore, disturbance calls were produced as a rapid series with an interpulse interval of 26–31 ms whereas advertisement call patterns were less stereotyped and ranged from <100 to 450 ms. Multicycle pulses distinguished U. canosai from other sympatric sciaenids."

Sound Name Quotes

"Disturbance calls were produced when captive U. canosai were startled, chased with a net or grabbed by the tail. Calls were unusual for sciaenids because each pulse consisted of multiple cycles. The number of cycles per pulse and dominant frequency did not change with U. canosai size, but pulse duration and interpulse interval increased. Advertisement calls were recorded from unseen choruses in the field and confirmed with captive individuals in a large tank. Advertisement calls were recorded throughout the known range of the species in Uruguay indicating a continuous belt of spawning populations. Tank recordings of the same individuals permitted explicit comparisons between the two calls. Advertisement call pulses averaged 2·4 more cycles (11·0–8·6) although pulses of both calls were basically similar as were durations and dominant frequencies. Pulse number, however, differed markedly, averaging 13·6 and 3·4 pulses for disturbance and advertisement calls respectively. Furthermore, disturbance calls were produced as a rapid series with an interpulse interval of 26–31 ms whereas advertisement call patterns were less stereotyped and ranged from <100 to 450 ms. Multicycle pulses distinguished U. canosai from other sympatric sciaenids."

"Additionally, passive acoustic monitoring was used to chart the position of calling U. canosai to compare the position of spawning choruses with known distributions (Haimovici & Viera, 1986)."