The Territoriality of Fishes
Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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The Territoriality of Fishes

Mantis Shrimp Picture
A reader commented in response to my post about triggerfish bites, "Well, it certainly wasn't the fish pictured here that produced the bite....look at her, so innocent. Why her picture just screams 'Who me? I didn't do anything.'" This raises the important issue of wild marine animals versus domesticated animals, and how their behaviors differ. From wilderness medicine and emergency medicine perspectives, this is quite important, because animal bites are a common cause of medical emergencies.

Wild animals are often characterized as "unpredictable." They are, of course, very predictable with regard to many behaviors, such as predation, mating, feeding, migration, physical development, and so forth. What most people mean when they invoke the "unpredictable" moniker is that, no matter how tame or friendly a wild animal may appear, it is nearly impossible to predict when it make become hostile toward humans. We are very familiar with episodes in which tamed animals, such as big cats, have turned on their trainers, brutally attacking them and inflicting serious, sometimes, fatal, injuries.

Many animals have territories (areas) that they protect. These range from the immediate vicinity when they are feeding to an extended area when guarding their young. Some animals display threat gestures, such as puffing out skin, displaying colorful plumage, changing colors, erecting fur, growling, or barking. Others appear unperturbed until the moment that they charge and attack the perceived threat.

In the marine environment, some animals are "territorial." The triggerfish falls into this category when guarding a "nest." Other animals, such as mantis shrimp, will become aggressive if their domiciles are approached. Seemingly friendly animals, such as schooling dolphins, will occasionally become defensive and actively seek to repel invaders.

Animals raised in captivity or trained from infancy are more likely to be tolerant of humans and to accept their intrusion. Over time, wild animals can become habituated to human presence, but that should not be equated with transforming them into household pets. While stingrays handled repeatedly in a location like "Stingray City" in the Cayman Islands may carry a lower incidence of defensive attacks upon humans, they have the potential to inflict nasty stings, and have bitten more than a few persons who placed body parts close to their mouths. Sharks can become accustomed to being fed by humans and thereby not be as prone to flee in their presence, but under no circumstance should that be interpreted to mean that they will not attack given the appropriate stimulus.

One should adhere to the usual rules for avoiding unnecessarily injurious encounters with wild marine animals:

1. Never corner an animal in such a manner that it does not have an easy escape route.
2. Do not handle animals. Do not attempt to ride upon animals.
3. Do not flash bright lights in the eyes of animals.
4. Do not tempt animals with food products.
5. Do not come between a mother and its young.
6. Do not interrupt an animal when it is feeding.
7. Do not reach blindly into holes and crevices.
8. If it is necessary to settle on the bottom (e.g., upon sand or rocks), take great care to inspect the area carefully so that you do not inadvertently trod upon a stingray, scorpionfish, or other animal with venomous spines.
9. When removing a captured marine animal from a net or a hook, take extreme care. The animal will often struggle with great strength.
10. Do not put your fingers anywhere near the mouth of a fish or other marine creature. Some of these animals have razor-sharp teeth or crushing grinding plates.

photo copyright Peter Lange at

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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.