<P> Sound - generating mechanisms are often different between genders . In some catfishes, pectoral fins are longer in males than in females of similar length, and differences in the characteristic of the sounds produced were also observed . Comparison between families of the same order of catfish demonstrated family and species - specific patterns of vocalization, according to a study by Maria Clara Amorim . During courtship behavior in three species of Corydoras catfishes, all males actively produced stridulation sounds before egg fertilization, and the species' songs were different in pulse number and sound duration . </P> <P> Sound production in catfish may also be correlated with fighting and alarm calls . According to a study by Kaatz, sounds for disturbance (e.g. alarm) and agonistic behavior were not significantly different, which suggests distress sounds can be used to sample variation in agonistic sound production . However, in a comparison of a few different species of tropical catfish, some fish put under distress conditions produced a higher intensity of stridulatory sounds than drumming sounds . Differences in the proportion of drumming versus stridulation sounds depend on morphological constraints, such as different sizes of drumming muscles and pectoral spines . Due to these constraints, some fish may not even be able to produce a specific sound . In several different species of catfish, aggressive sound production occurs during cover site defense or during threats from other fish . More specifically, in long - whiskered catfishes, drumming sounds are used as a threatening signal and stridulations are used as a defense signal . Kaatz investigated 83 species from 14 families of catfish, and determined that catfishes produce more stridulatory sounds in disturbance situations and more swimbladder sounds in intraspecific conflicts . </P> <P> Catfish are easy to farm in warm climates, leading to inexpensive and safe food at local grocers . About 60% of U.S. farm - raised catfish are grown within a 65 - mile (100 - km) radius of Belzoni, Mississippi . Channel catfish (Ictalurus punctatus) supports a $450 million / yr aquaculture industry . The largest producers are located in the Southern United States, including Mississippi, Alabama, and Arkansas . </P> <P> Catfish raised in inland tanks or channels are considered safe for the environment, since their waste and disease should be contained and not spread to the wild . </P>

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