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Cal Poly Pomona

Introduction

Most people know that whales make sounds, but many other aquatic animals are also noisy. Some fishes use sound to confuse predators, or to sense their environment, but most use sound to communicate with others of their species. These “talking fish” make sound in a variety of ways, but the sounds are almost always amplified by the swim bladder, a gas-filled sack that shares its origins with our own lungs.

Biotrek currently focuses on sound-producing catfish of tropical waters. These species produce sound by rubbing the bases of their pectoral spines against their pectoral girdles (almost as if you could move your arm in your shoulder socket and make noise).

For each of these fishes, there is a recording of their sound (provided by Dr. John P. Friel of Cornell University) and a sound spectrogram or sonogram, which shows the changes in frequency over time. These are similar to “voice-prints.” (See Technical Details to find out what these mean, and how they are made.)