The blue catfish, Ictalurus furcatus, is an invasive species introduced to Virginia in 1974 and is the largest catfish in the United States. Like other Ictalurids, they are capable of producing disturbance calls via stridulation of the pectoral spine. These sounds can be made in air and water, and catfish can be preyed upon by both aerial and underwater predators. I characterized these putative distress calls by recording them in air and in the fish’s natural habitat. Sounds exhibited a wide variation in acoustic parameters relative to fish ontogeny: larger fish produced higher amplitude sounds with lower frequency bands. Sweep and pulse duration increased with fish size, but pulse rate and the number of pulses per sweep decreased. Sounds were more robust in water with a 1400 fold increase in sound pressure compared to air. Frequency response was much more peaked underwater with a considerable amount of high frequency absorption. These sounds appear to be better adapted to water, suggesting that their use in air may be inconsequential.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-1138 |
| Date | 06 August 2010 |
| Creators | Ghahramani, Zachary |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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