Taxonomy of Finfish

1.1.1 Introduction

Aquatic vertebrates that have gills throughout life and limbs, if any, in the shape of fins.

• Fishes constitute slightly more than one-half of the total number of approximately 48,170 recognized living vertebrate species.
• There are descriptions of an estimated 24,618 valid species of fishes.
• Number of extant fish species may be close to 28,500.
• Of the 482 fish families with living species recognized, the eight largest families, each with over 400 species, contain approximately 33% of all species.
• These families, in the order of decreasing numbers of species are Cyprinidae, Gobiidae, Cichlidae, Characidae, Loricariidae, Labridae, Belitoridae and Serranidae.
• About 66% of the species in the eight largest families are freshwater fishes, where as about 40% of all fishes occur in or almost always in freshwater.

Classification

It is the practice of arranging organisms into groups or categories.  

Taxa (Taxon)

Groups of organisms recognized in a classification and given biological names (e.g. Cypriniformes, Cyprinidae, and Cyprinus)

Category

The level or rank at which the taxon is placed (e.g. order, family and genus)

Systematics  

• It is a biological science that discovers names, determines relationships, classifies and studies evolution of living organisms.
• It is a synthesis of many kinds of knowledge, theory and method applied to all kinds of classifications of organisms.
• It includes taxonomy.
• Our knowledge of biodiversity is incomplete. Only 1.70 million of the earth is estimated 10-100 million sp have been scientifically erected, named and classified. In the marine biota, 3,40,000 sp are known including many unnamed species. It could be impossible to deal with the enormous diversity if it were not ordered and classified.
• Systematic zoology solves this problem and develops many methods and principles to make this task possible.
• It has a broader base than genetics, biochemistry and physiology.  

Taxonomy

• The term ‘taxonomy’ is derived from the Greek word ‘taxis’ - arrangement and ‘nomos’ – law.
• The name taxonomy was first proposed by Candolle (1813)
• It is the theory and practice of classifying organisms based on the similarities and differences by following certain internationally accepted principles, laws, rules and regulations.

Identification

Placing the individual to each taxon by deductive procedure.

Classification 

Ordering of animals into groups on the basis of their relationships.