Trawling effects on marine biodiversity

Trawling effects on marine biodiversity

Trawling is an approach in fishing that involves pulling fishing nets through nets behind at least one boat. In trawling, a special net used for fishing is known as a trawl. It is same as online courses to help you prepare for the GRE testduring exams time.

Trawling is different from trolling. Students often in the exam preparation process confuse the two terms. The difference between the two methods is while trolling is for recreational and commercial fishing, trawling is mainly done for commercial purposes. Besides, trawling is used as a scientific sampling method.

The fishing boats used for trawling are called trawlers or daggers. They vary in size from small to large depending on the user’s preferences.

Trawling is divided into two:-

Bottom trawling

This refers to towing trawl close or along to the sea bed.

Bottom trawling

Midwater trawling

Refers to towing the trawl through free water just above the sea bed.

Midwater trawling

Pros of trawling

Provides human food such as fish for consumption

Creation of employment opportunities

Cons of trawling

It causes overfishing hence extinction of a particular fish species. Species that can be extinct include, eel, Atlantic code, sea bass, sturgeon, etc

Kills seabed microorganisms as a result of heavy fishing machinery moving across the seabed.

Trawling is a fishing method that adversely affects the environment. Trawling is a fishing method that is discouraged due to the lack of selectivity; also, it causes a lot of damage to the seabed.

Selectivity effect

Trawling is a method of fishing kicked off in the 15th century. Trawls used in fishing are non-selective. They sweep all the fish of all sizes. Both the desired and undesired in the market.

Some fish species end up being killed accidentally as the trawls sweep across the sea bed.

Trawls also catch unwanted fish species like sea turtles, sharks, dolphins.

In trawling, size selectivity will be controlled by cod-end’s mesh size. The cod end is the part of the fish where the fish are stored when they enter the trawl nets. Some fishermen make them smaller and therefore catch very small fishes hence extinction of a particular species of fish in the sea.

To reduce the catch of unwanted size of fish species, grinds of nets should be fitted to the parts of the trawl to allow a given size of fish to escape while retaining the rest.

Damaging of environment

Trawling has been so controversial because it causes a lot of damage to the sea environment. Bottom trawling involves the act of towing heavy fishing gear above the seafloor. This large sea gear causes environmental destruction in the ocean such as coral shattering and damage of fish habitats. The weeds, which are used as fish food, are also destroyed.

The impact caused by these heavy fishing gears reduces the species diversity and further causes ecological changes in the fishing area.

Trawling directly kills various fish species around the world. For instance, this method of fishing kills coral reefs by breaking them and burying them in sediments. Besides, it kills coral reefs by wounding coral tissues hence being exposed to infections

The sea ecosystem plays a concrete role in the global functioning of the planet. The functions largely depend on deep-sea diversity. Trawling along the seas has major impacts on sea biodiversity and it causes their degradation. It causes the collapse of benthic biodiversity and ecosystem functions. There is a need for immediate actions to sustain fisheries in the deep sea from destruction.

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