Atlantic Herring facts for kids
Quick facts for kids Atlantic herring |
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C. harengus
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| Clupea harengus Linnaeus, 1758
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The Atlantic Herring is a type of herring fish. You can find it on both sides of the Atlantic Ocean. This fish can grow up to 45 centimeters (about 1.5 feet) long and weigh more than half a kilogram (over 1 pound).
Atlantic herring are known as "school fish." This means many of them swim together in huge groups called "schools" or "swarms." Some of these schools have been measured to be as big as 4 cubic kilometers. That's like a cube with sides 1.6 kilometers long! Scientists have estimated that these huge schools can contain up to 4 billion individual fish.
Sadly, like many other fish, Atlantic herring are facing a big problem: too much fishing. This is called "overfishing," and it has caused the number of herring to drop a lot. People often fish for herring because they contain healthy Omega Fatty Acids, which are good for memory and brain function.
Natural predators of the Atlantic herring include seals, cod, other large fish, and some types of whales.
Contents
Description
Atlantic herring have a body shape that is called fusiform. This means their body is shaped like a torpedo, which helps them swim fast and smoothly through the water. Inside their mouths, they have special parts called gill rakers. These act like a filter, trapping tiny zooplankton (small animals) and phytoplankton (tiny plants) from the water as the fish swim. This is how they eat.
Atlantic herring are generally delicate fish. They have large, sensitive gills, and their scales can easily fall off if they touch other things.
These fish have moved away from many estuaries (places where rivers meet the sea) around the world. This is because of too much water pollution. However, in some estuaries that have been cleaned up, the herring have started to return. When you find their tiny larvae (baby fish) in the water, it's a good sign that the water is cleaner and has more oxygen.
Range and habitat
Atlantic herring live in the North Atlantic Ocean. You can find them in places like the Gulf of Maine, the Gulf of St Lawrence, the Bay of Fundy, the Labrador Sea, the Davis Straits, the Beaufort Sea, the Denmark Straits, the Norwegian Sea, the North Sea, the English Channel, the Celtic Sea, the Irish Sea, the Bay of Biscay, and the Sea of the Hebrides. Even though they live in northern waters near the Arctic, they are not considered an Arctic species.
Baltic herring
There's a smaller type of herring found in the inner parts of the Baltic Sea. This "Baltic herring" is also less fatty than the true Atlantic herring. A famous Swedish dish called surströmming is made from Baltic herring.
Life cycle
Herring become ready to have babies when they are about 3 to 4 years old. Once they are mature, they can live for 12 to 16 years. Atlantic herring lay their eggs during the summer. They do this in estuaries, close to the coast, or in areas further out in the ocean called offshore banks.
Like most other fish, fertilization happens outside the body. The female herring releases between 20,000 and 40,000 eggs into the water. At the same time, the males release their sperm, so they mix freely in the sea. Once an egg is fertilized, it sinks to the seabed. Its surface is sticky, so it attaches to gravel or plants. The egg will only hatch if the water temperature stays below 18.9 degrees Celsius (66 degrees Fahrenheit). When the larvae hatch, they are only 3 to 4 millimeters long and are clear, except for their eyes, which have some color.
Ecology
Herring-like fish are super important and are the most common fish group on Earth. They are key in turning tiny zooplankton into fish. They eat small creatures like copepods, arrow worms, tiny shrimp-like animals, and krill that live in the open ocean.
On the other hand, herring are a main food source for many bigger animals. They are often called "forage fish" because so many other animals eat them.
Many different animals hunt herring. These include Orcas, cod, dolphins, porpoises, sharks, rockfish, seabirds, larger whales, squid, sea lions, seals, tuna, salmon, and of course, fishermen.
Herring larvae and young fish eat very small things like tiny snails, diatoms, and other types of plankton.
Schooling
Atlantic herring are famous for forming huge schools. These schools can contain thousands, hundreds of thousands, or even millions of individual fish. They travel across the open oceans together.
Scientists have estimated that herring schools in the North Atlantic can take up to 4.8 cubic kilometers of space. Imagine a cube with sides almost 1.7 kilometers long, filled with fish! There can be between 0.5 and 1.0 fish in every cubic meter of water within the school. That's billions of fish in one school!
These schools have a very organized way of swimming that helps them keep a steady speed. Herring from the same group usually travel in a triangle shape between their spawning grounds (where they lay eggs), their feeding grounds (where they eat), and their nursery grounds (where young fish grow up).
Herring have excellent hearing, which helps their school react very quickly to avoid predators. When a predator like a killer whale or a diver approaches, the herring school will move away, forming an empty space around the predator. From above, this space looks like a doughnut!
Scientists are still trying to fully understand why fish school. Some ideas are that it confuses predators, makes it harder for predators to find them, helps them find their way, or helps them hunt together. However, schooling also has downsides, like using up oxygen and food quickly, and waste building up in the water.
On calm days, you can sometimes spot herring schools on the surface from far away because of the small waves they create. At night, you might see them because they make the surrounding plankton glow (this is called "firing" or bioluminescence). Underwater videos show that herring are always swimming, reaching speeds of up to 108 centimeters (about 42 inches) per second. They can swim much faster when trying to escape danger.
Images for kids
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Global capture of Atlantic herring in tonnes reported by the FAO, 1950–2010
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Purse seining for Atlantic herring -
Harvesting with the purse seine -
The catch
See also
In Spanish: Arenque del Atlántico para niños
