How Many Fish are There in The Sea

Introduction

There are millions of species of fish in the sea. Scientists have estimated that there are about 3.5 trillion fish in all the oceans combined. There are many organisms in the world and it becomes very difficult to count or classify them. They were classified by many scientists in many ways. The most famous and widely used is the one given by scientist Robert Whittaker. These have been broadly categorized into 5 Kingdoms by considering the type of cell. These Kingdoms are Monera, Protista, Fungi, Plantae and Animalia. Fishes are included in the kingdom Animalia.

Biological Classification

Kingdom: Animalia

Phylum: Chordata

Clade Olfactores

Subphylum: Vertebrata

Division Agnatha(without jaws) and Gnathostomata (with jaws)

Super Class Pisces (bears fins)

Class I Chondricthyes (Cartilagenous fishes)

Class II Osteicthyes (Bony fishes)

Kingdom Animalia

Every living organism in the world has a presence of cells. This is the largest among all kingdoms. All types of animals including humans are included in the kingdom. These generally have eukaryotic cells and are multicellular. The cell walls are absent. They are heterotrophic i.e depend on others for food.

Phylum Chordata

These are also called chordates because they have tubular nerve cords and below that, they have notochords throughout the length of organisms. This provides structure to organisms. These have a pair of gills and a tail around the anus. It is further divided into proto-Chordata and Vertebrata.

Fishes form a part of the subphylum Vertebrata. The superclass is Pisces and is further divided into classes named Chondrichytes, Osteichthyes and Cyclostomata.

Common Classification

In common life, They can be divided into saltwater and freshwater species. Based on their physical shape they can be divided into Round and Flatfish. On basis of flesh, they can be divided into white fishes and oily fishes. Some of the common freshwater fishes are Rohu, Common Carp and Catla. Some of the common marine fishes are Hilsa, Sardines, Mackerels and Pomfrets.

Structure of a Fish

The existence of fishes has been around for a very long time, around 450 million years ago. These are aquatic animals living in the water. There are around 31,000 species found in water. However, they have a huge population so there is a possibility of many more species available which are unknown to mankind. They live underwater and therefore, have gills to breathe instead of lungs. They have scales and fins on the body.

Fins are used for balancing the body during swimming and maintaining balance. Mostly, all are cold-blooded and lay many eggs. Different species have adapted to different environments and live in different water bodies. They generally feed on aquatic plants and worms and insects present in the water.

Applications

Many of the fishes are used for eating. Fishes can reduce the risk of cancers, Shin and hair problems and cardiovascular disease. They are used to make medicines. They are used to make oils and glues. They can be fed to animals. They can be used as pets. They act as a source of occupation for fish farmers.

Fun Facts

• Catfish have over 27,000 taste muds which are 3 times more than humans.

• Fish can drown in water due to a lack of oxygen.

• Fish cannot chew and may die if they try to.

• The fastest fish in the world i.e Sailboat can swim at speed of 110 km/hr.

• Fishes can communicate through motions and sounds.

• Sharks are the largest fish in the world.

• The grey white shark can raise their temperature in cold water.

• There are around 450 species of fish which can change their sex as per their needs and can fertilise their eggs.

Conclusion

There are millions of fish in the world and many species are found and there are chances of others being possible also.