Why do mackerel swim all the time?

Why do Mackerel Swim All the Time?

Mackerel are one of the most popular types of fish in the world, and their unique swimming behavior has puzzled scientists for decades. Unlike other fish species, mackerel constantly swim, even when they are not feeding or migrating. This article explores the different reasons why mackerel swim all the time.

Habit or Instinct?

The first question to consider is whether swimming all the time is a habit or instinctual behavior for mackerel. Scientists believe that it is a combination of both. In the wild, mackerel are constantly on the move, searching for food, avoiding predators, and migrating to mating grounds. This behavior has been ingrained in their genetic makeup over thousands of years. However, captive mackerel have also been observed to swim continuously, even when they are provided with ample food and a safe environment. This suggests that swimming is also a learned behavior that is reinforced over time.

Nutrition and Feeding Habits

Mackerel are voracious eaters and consume a variety of prey items such as small fish, squid, and plankton. Swimming constantly allows them to cover more ground and thereby increases their chances of finding food. Additionally, their streamlined bodies and swimming speed make them efficient hunters, allowing them to catch prey more easily.

Migration and Reproduction

Mackerel are known to migrate long distances in search of suitable breeding grounds. Swimming continuously ensures that they are always moving towards their destination, even when they are not actively searching for food. This behavior also ensures that the eggs and sperm are well mixed, increasing the chances of successful fertilization.

Avoiding Predators

Mackerel are a primary food source for many predators such as larger fish, birds, and marine mammals. Constant swimming is a strategy employed by mackerel to avoid being caught. Swimming in schools also provides safety in numbers, making it harder for predators to single out individual fish.

Energy Conservation

While it may seem counterintuitive, swimming all the time actually conserves energy for mackerel. When they stop swimming, their body temperature drops, making them less efficient at digesting food and swimming. By constantly swimming, they maintain a consistent body temperature, which allows them to swim faster and utilize their energy more efficiently.

Buoyancy Control

Mackerel are naturally buoyant and must swim constantly to avoid sinking. Their swim bladder, which regulates buoyancy, is relatively small compared to other fish, and they rely on swimming to maintain their position in the water column.

Social Interaction

Mackerel are social creatures and swim in large schools. Constant swimming allows them to maintain their position within the school and communicate with each other through body language and pheromones.

Maintaining Body Temperature

Lastly, mackerel are cold-blooded animals, which means that their body temperature is regulated by the environment. Swimming all the time ensures that they are always in motion, which helps them maintain a consistent body temperature.


In conclusion, mackerel swim all the time for a variety of reasons. It is a combination of instinctual behavior, learned behavior, and practicality. Swimming allows them to find food, migrate, avoid predators, conserve energy, maintain buoyancy, interact socially, and maintain a consistent body temperature. While it may seem exhausting to swim constantly, it is a necessary behavior for the survival of the species.

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