*The swim bladder is a large chamber of air located in the abdominal cavity in most bony fishes (Fig. 12.23 and 12.25)). *Marshall (1967) reported that swim bladder acts as resonator if fishes. *Air gets into the swim bladder in one of two different ways, depending upon the species. a) In some species, there is a duct between the swim bladder and esophagus (the pneumatic duct) – this sort of swim bladder is called “physostomous”. *These fish come to the surface and "gulp" air that is directed via this duct into the swim bladder. b) In other fishes, including all of those that live deep in the ocean, fishes have a special gas gland and rete mirabile, within the wall of the swim bladder, which is called a “physoclistous” swim …show more content…
*Stridulatory sounds are produced by friction of teeth, fins, spines or bones. *In fishes, stridulation often occurs during feeding when jaw teeth or pharyngeal teeth are gnashed together. *Stridulation may be used intentionally to produce sound as a fright response or territorial display. *Stridulatory sounds may be modified or amplified by the swim bladder. *The component frequencies of stridulatory sounds range from < 100 to >8000 Hz, while predominant frequencies are generally between 1000 and 4000 Hz.. *Examples of fish species that produce sound by stridulation include marine catfishes and sea horses. * In some species such as the grunts (family haemulidae), the swim bladder is hypothesized to function as a resonator to amplify stridulatory