According to earlier surveys, there were nine sound types in areas adjacent to the estuaries of nine major rivers in Taiwan, and the frequency range of the H-type sound was as high as 6 kHz. The producers of this sound type have not been defined yet. Sea catfish can make two kinds of sounds: stridulatory sound and drumming sound. The former is pulsed, broad-band and high-frequency, whereas the latter is harmonic, and low-frequency (less than 1 kHz). Spotted catfish (Arius maculates) is the most common demersal species in the west coast of Taiwan. The aims of the study were (1) to find out if H-type sound is presence in Cigu lagoon; (2) to describe the disturbance (hand-held) sounds emitted by A. maculates; (3) to find clues to support that the stridulatory sound of A. maculates is the H-type sound; (4) to find if there is sexual difference in the sounds of A. maculates; (5) to find the relationship between sound characteristics and intrinsic characters of the fish; (6) to define the reproductive season of A. maculates; (7) to find out if there is correlation between the spawning season of A. maculates in Cigu lagoon and presence of the high-frequency sounds in the lagoon. Bimonthly sound recordings were made in Cigu lagoon between February to December 2009. Pulsed, broad-band and high-frequency sounds were present in April, June, and August; number of sounds per minute was higher in August (mean: 52.9 sounds/ min). The sound were characterized by: sound duration: 160.6 ¡Ó 16.6 ms, dominant frequency: 2840 ¡Ó 867.3 Hz, pulse period 12.6 ¡Ó 0.45 ms, pulse duration: 6.0 ¡Ó 0.82 ms, inter-pulse-interval: 6.6 ¡Ó 0.84 ms. The stridulatory sounds of A. maculates are pulsed, broad-band and high-frequency - sound duration: 64.0 ¡Ó 16.74 ms, dominant frequency: 1251 ¡Ó 419.8 Hz, pulse period 7.7 ¡Ó 2.69 ms, pulse duration 5.3 ¡Ó 1.69 ms, inter-pulse-interval 2.4 ¡Ó 1.93 ms. Drumming sounds of A. maculates are harmonic, low frequency - sound duration: 58.5 ¡Ó 25.54 ms, dominant frequency: 442 ¡Ó 96.3 Hz fundamental frequency: 163 ¡Ó 30.98 Hz, pulse period: 6.3 ¡Ó 1.21 ms, pulse duration: 6.3 ¡Ó 1.19 ms. There was significant sexual difference in the stridulatory sound characters including pulse period, inter-pulse-interval, pulse number; females are higher than males in these parameters. There was significant sexual difference in the drumming sound (including dominant frequency) as well; males are higher than females in these parameter. Pulse period of the stridulatory sounds increased significantly with increasing standard body length. Pulse period and pulse duration of the drumming sounds both increased significantly with increasing standard body length, whereas dominant frequency and fundamental frequency both decreased significantly with size. GSI and oocyte diameters were higher in February, April, and June with a peak in April. Reproductive period was considered occurring from April to August (i.e. in spring and summer). This reproductive period coincides with the peak of vocalization. Result of ANOSIM indicates that, H-type sound is significant different from the stridulatory sound of A. maculates - they are in different groups. As the sound source might be at a distance from the recording site, energy in the high frequency range might decay with distance, whereas low frequency range might be cutoff as well. As A. maculates is the only soniferous spices in Cigu lagoon that can emit high-frequency sounds, possibility remains high that the high frequency sound, which resembles the H-type sound, in Cigu lagoon is actually produced by the spotted catfish despite of the difference in frequency-domain features of the sounds.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0903110-144125 |
| Date | 03 September 2010 |
| Creators | Lin, Szu-Ying |
| Contributors | Bao-Sen Shieh, Hin-Kiu Mok, Ruey-Chang Wei |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903110-144125 |
| Rights | campus_withheld, Copyright information available at source archive |
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