Skin, Mucus Prevent Abrasion

the head of a blenny fish with blue and yellow markings sticks out between orange, red and white algae and coral

Biological Strategy

Tusk

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Image: Prilfish / Flickr / Some rights reserved

Manage Mechanical Wear

A living system is subject to mechanical wear when two parts rub against each other or when the living system comes in contact with abrasive components in its environment, such as sand or coral. Some abrasive components are a constant force, such as finger joints moving, while others occur infrequently, such as a sand storm moving across a desert. Living systems protect from mechanical wear using strategies appropriate to the level and frequency of the source, such as having abrasion-resistant surfaces, replaceable parts, or lubricants. For example, human joints like shoulders and knees move against each other all day, every day. To protect from mechanical wear, a lubricant reduces friction between the cartilage and the joint.

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Fish

Class Agnatha (“without jaws”), Class Chondrichthyes (“cartilage fish”), Superclass Osteichthyes (“bone fish”): Sharks, eels, snapper, hagfish

The fish are a diverse group, comprising multiple classes within Phylum Animalia. The most well-known classes are Chondrichthyes, which has sharks and rays, and superclass Osteichthyes, which has all bony fish like cod and tuna. Unlike other vertebrates, fish only live in water. They use special adaptations like fins, gills, and swim bladders to survive. Most are ectothermic, meaning their body temperature depends on the water temperature around them. Over half of all vertebrates are fish. They’re found from the bottom of the sea to high mountain lakes.

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The skin of blennies prevents abrasion through tough skin and secreted mucus.

Image: Nick Hobgood / Wikimedia commons /

Australian blenny (Ecsenius axelrodi) in East Timor.

Image: George Chernilevsky / Wikimedia commons /

Salaria pavo (Risso, 1810). Peacock blenny male. This funny predatory fish was caught in the Black sea. Wet matter was used as a background to prevent damage to its skin. After very short photosession the fish was released back to the sea. This fish is able to change colour, like a chameleon. Geogoding of the location at which it was caught and photographed are the same.

“The skin of intertidal fishes is generally tough, and so it can withstand repeated scraping against the substratum. Some of the fishes (such as blennies and clingfishes) have no scales; in others (such as gunnels and pricklebacks) the scales are greatly reduced and in still others (the gobies) they are attached very firmly. Many of the fishes secrete large amounts of mucus, which may provide lubrication in confined spaces.” (Horn and Gibson 1988:60-61)

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