Seine fishing

People use large nets to catch fish.

These nets hang deep in the water. Weights hold the bottom edge down. Floats keep the top edge up.

Some nets go from the beach. Other nets go from a boat. One kind of net is a purse seine. It has rings along the bottom. A line pulls the rings tight. This keeps fish from swimming away. This helps people catch fish for food.

Seine fishing uses a large net to catch fish.

The net hangs deep in the water. Weights hold the bottom edge down. Floats keep the top edge up. People can use these nets from a beach. They can also use them from a boat.

One common type is the purse seine. It has rings along the bottom edge. A line pulls these rings closed. This works like a drawstring on a purse. It stops fish from swimming down to escape. This method is good for fish that swim in groups. This includes tuna, mackerel, and herring.

Another type is the Danish seine. This net is shaped like a cone. It has two long wings. A boat drags the net in a big circle. This moves the fish into a central bag. People have used seine nets for a very long time. The Māori people used nets made of green flax. They used stone weights and wood floats. These nets could be over a kilometer long!

Seine fishing is a clever way to catch fish using a large net. This net is called a seine. It hangs straight down in the water. Weights hold the bottom edge down. Floats keep the top edge up.

People can use these nets from the shore. This is called a beach seine. Other people use boats to do the fishing. These boats are called seiners.

This method is special because it encloses the fish. This is different from a gillnet that snares them.

One common way to fish is with a purse seine. This net has rings along the bottom. A special line called a purse-line goes through the rings. When people pull this line, the rings close together. It works just like a drawstring on a purse.

This stops fish from swimming down to escape. It is great for catching fish that swim in groups. This includes tuna, mackerel, anchovies, and herring. It also works for salmon before they swim into rivers.

People have used seine nets for a very long time. Stone Age societies used them in the past. The Māori people used large canoes for their nets. Their nets could be over one kilometer long! They wove them from green flax. They used stone weights and wood or gourd floats. Native Americans on the Columbia River used spruce root or grass. They used cedar sticks as floats to move fish together.

History shows these nets in many old places. Egyptian tomb paintings from 3000 BCE show them. The poet Ovid wrote about them in ancient Rome. He mentioned using cork floats and lead weights.

In the 1950s, a new tool called a power block arrived. It is a machine that helps haul the nets. This tool changed how purse seine fishing works. Some boats now use a drum seine instead. This uses a big drum to store the net. It is much faster than a power block.

Different parts of the world have their own rules. Kenya outlawed beach seines in 2001. In Sri Lanka, you cannot use purse seines near the shore. You must get permission to use them in the deep sea.

Some nets, like the Danish seine, work best in certain areas. A Danish seine is shaped like a cone. It has two long wings and a bag. A boat drags it in a big circle. This moves fish into the central bag. This method is very useful in northern regions.

Seine fishing is a specialized method used to capture fish by surrounding them with a large net. This net is called a seine. It hangs vertically in the water column. Weights hold the bottom edge down to the seabed. Floats keep the top edge buoyant at the surface.

Unlike a gillnet, which snares fish by their gills, a seine works by enclosing them within a perimeter. This method is essential for catching large groups of fish at once. It can be performed from the shore, known as beach seining, or from specialized boats called seiners.

One of the most common techniques is purse seine fishing. This method relies on a specific mechanism to trap fish. The net features a series of rings along its bottom edge. A specialized line called a purse-line passes through every ring. When the crew pulls this line, the rings draw close together. This action functions much like a drawstring on a traditional purse. It prevents fish from "sounding," which is the act of swimming downward to escape.

This technique is highly effective for schooling species like sardines, mackerel, anchovies, herring, and certain tuna. It also works for salmon during their aggregation before they spawn in rivers.

Another distinct method is the Danish seine, also known as an anchor seine. This net is shaped like a cone with two long wings and a central bag. To use it, a seiner or an auxiliary boat deploys the net from a fixed point, such as an anchored marker buoy. The vessel then sweeps in a large circle, dragging the wings through the water. This circular motion herds the fish into the central bag.

This method is best for demersal fish, which live on or near the sea floor. It is particularly useful in northern regions where the seabed is flat but too rough for traditional trawling.

In parts of Canada and the western United States, fishermen use drum seining. This method was adopted in the late 1950s and is used exclusively in regions like British Columbia. Instead of using a pulley, it uses a horizontally mounted drum to haul and store the net. The net passes over a roller and through a spooling gear. This gear moves across the stern of the boat to guide the net.

Drum seining offers several advantages. It allows the net to be hauled in at more than twice the speed of a power block. It is also a safer process because it requires less overhead handling. Furthermore, the drum system can be operated with fewer deckhands.

History shows that seine fishing has been a vital human activity for millennia. Stone Age societies used these nets long ago. The Māori people used large canoes to deploy nets that could exceed one kilometer in length. These nets were woven from green flax and used stone weights and gourd floats. Native Americans on the Columbia River wove nets from spruce root fibers or wild grass. They used cedar sticks as floats because their movement helped frighten fish into groups. Ancient records also document seining. Egyptian tomb paintings from 3000 BCE depict these nets. The poet Ovid also wrote about the use of cork floats and lead weights in ancient Rome.

Technological advancements have significantly changed the industry. In the 1950s, the introduction of the Puretic power block revolutionized purse seining. This is a mechanized pulley used to haul in heavy nets. Before this, hauling was much more labor-intensive. Modern power blocks are usually driven by hydraulic pumps from the ship's engine. They allow the crew to control the speed and direction remotely.

Today, a minimum of three to five people are required to manage the various lines and the web during a power block operation.

While efficient, seine fishing must be managed carefully to protect the environment. Experts rank purse seine fishing as one of the most sustainable commercial methods when used correctly. This is because it can result in small amounts of by-catch, which are fish caught unintentionally. However, the percentage of by-catch increases if the nets are used near fish aggregating devices. Some countries have strict regulations to prevent overfishing. For example, Kenya outlawed beach seines in 2001, and Sri Lanka prohibits purse seining near the shore. These rules help ensure that fish stocks remain healthy for the future.