Atlantic herring

The herring is a small fish.

It lives in the big Atlantic Ocean. These fish swim in huge groups. One group can have billions of fish!

They eat tiny things in the water. They use their mouths to catch food. This helps them grow.

Many big animals eat them. Seals and whales like to eat herring. Even big fish hunt them.

Herring are very fragile. They can lose their scales easily. They like clean water to live in.

These fish are very important. People catch them for food. They are a big part of life by the sea.

The Atlantic herring is a very common fish.

They live in the North Atlantic Ocean. These fish swim in massive groups called schools. One school can have as many as four billion fish!

Herring use special parts in their mouths. These are called gill rakers. They help the fish filter food from the water. They eat tiny things like krill and small fish. Many large animals hunt herring. These include whales, seals, and cod.

Herring are very fragile. They can lose their scales easily. They also need clean water to live well. If the water is dirty, they may leave.

These fish are important to people. Many places catch them for food.

This helps the local economy. In the Baltic Sea, there is a type called Baltic herring. This fish is the national fish of Estonia. Herring can live for 12 to 16 years once they are grown. They reach this stage when they are 3 to 5 years old.

The Atlantic herring is one of the most abundant fish in our world.

These fish live in the North Atlantic Ocean on both sides. They often gather in huge groups called schools. Some schools are so large they hold four billion fish!

These massive groups are very important for the ocean. They act as a bridge between tiny life and big animals. Many different creatures depend on them to survive every day.

Herring have a very specific way of eating and growing. They have special parts in their mouths called gill rakers. These act like tiny sieves to filter food from the water. They eat small things like krill, copepods, and tiny fish. To make new life, females release up to 40,000 eggs into the sea. The eggs are sticky and attach to gravel or weeds on the sea floor. They only grow well if the water stays below 19 degrees Celsius.

People have worked with these fish for a very long time. In the Baltic Sea, a type called Baltic herring is very popular. This fish is the national fish of Estonia. In the past, people caught many autumn-spawning herring in the Baltic. However, a cooling period in the mid-16th century changed things. This was part of the Little Ice Age. Because of the cold and overfishing, those fish almost disappeared. Now, most fish caught there are spring-spawning populations.

There are many interesting facts about where herring live. They can be found from South Carolina all the way to Greenland. They also live from the Baltic Sea to Novaya Zemlya. In the North Sea, scientists see four main groups. Some spawn in August near the Scottish coasts. Others spawn in the Baltic Sea or the Southern Bight of Downs. Even the Zuiderzee herring once lived there, but they vanished when the Dutch drained that area.

Herring are a vital part of how many animals live. They are a main food source for many predators. These include whales, seals, cod, dolphins, and even sharks. They also provide food for many different seabirds. Because they swim in such large, fast schools, it is hard for predators to catch them. They use their excellent hearing to react quickly to danger. This helps them stay safe while they travel across the vast, open ocean.

The Atlantic herring, known scientifically as *Clupea harengus*, is one of the most abundant fish species on Earth.

These fish belong to the family Clupeidae and play a vital role in marine ecosystems. They act as a primary link in the food web by converting tiny plankton into energy for larger animals. Because they exist in such massive numbers, they are considered one of the most important fish groups on the planet. Their presence helps maintain the balance of life in the North Atlantic Ocean.

To survive and grow, Atlantic herring use a specialized feeding mechanism. They possess structures in their mouths called gill rakers. These act like fine sieves to filter the water as it passes through their gills. This process allows them to trap zooplankton and phytoplankton, which are tiny organisms floating in the sea. Their diet includes copepods, krill, mysids, and even small fish. By consuming these small creatures, herring move energy up the trophic levels of the ocean.

Atlantic herring are famous for their incredible schooling behavior. They are "obligate schoolers," meaning they naturally live in large, organized groups. These schools can consist of thousands, millions, or even billions of individuals. Some North Atlantic schools have been estimated to contain as many as four billion fish. These groups can occupy a massive volume of water, up to 4.8 cubic kilometers. Schooling provides several advantages, such as predator confusion and better orientation during long journeys.

Their movement is highly organized and follows specific patterns. A single stock often travels in a large triangular path. They move between their spawning grounds, their feeding grounds, and their nursery grounds. For example, herring may travel between Southern Norway and Iceland. This movement requires constant cruising, with speeds reaching up to 2 meters per second. They also use excellent hearing to sense danger, allowing the school to react instantly to predators.

The life cycle of a herring begins with external fertilization. A female releases between 20,000 and 40,000 eggs into the water. At the same time, males release milt to fertilize them. The eggs are quite small, measuring only 1 to 1.4 mm in diameter. Because they are sticky, the eggs adhere to seaweed or gravel on the sea floor. These eggs only mature if the water temperature remains below 19 degrees Celsius. In warmer water of 14–19 degrees Celsius, they mature in 6 to 8 days. In cooler water at 7.5 degrees Celsius, the process takes 17 days.

In certain regions, distinct subspecies like the Baltic herring (*Clupea harengus membras*) exist. The Baltic herring is smaller and contains less fat than the true Atlantic herring. This subspecies is culturally significant and was elected the national fish of Estonia in 2007. History shows how sensitive these populations can be to environmental changes. During the mid-16th century, the Little Ice Age caused temperatures to drop. This cooling, combined with overfishing, nearly wiped out the autumn-spawning populations in the Baltic Sea. Today, most fisheries in that area rely on spring-spawning populations.

Because herring are so central to the ocean, they support a vast array of predators. Many animals rely on them as a primary food source, including whales, seals, dolphins, and sharks. They are also vital prey for seabirds, cod, and tuna. This relationship makes them a "forage fish," meaning they provide the essential fuel for higher levels of the food chain. Humans also rely on them through large-scale fisheries, particularly in New England and the Canadian Atlantic provinces. Managing these fisheries is essential to ensure that herring populations remain stable for the entire ocean ecosystem.