Anatomy and Biology of Finfish


Dr. Amrutha Gopan


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Anatomy and Biology of Finfish

FSRM 1203(2-1-0)

Course Objectives

• To understand the internal and external anatomy of a fish in detail
• To identify the different parts of a fish and describe the function of each part
• To understand the internal organs and their functions
• To study the life forms of fishes with regard to their food and feeding habits, age, and growth followed by reproduction.
• To distinguish the fishes with respect to their feeding habits

Learning Outcomes

At the end of the course students should:
• have enhanced knowledge on anatomical features of a finfish
• able to distinguish the external and internal anatomy of various fishes
• understand the functions of important internal organs and their role in circulatory, respiratory, nervous, skeletal, excretory, reproductive,sensory systems
• explore how growth is estimated from wild fish stocks

Course Syllabus

Study of external and internal anatomy of important groups of finfish. Study of oral
region and associated structures. Digestive system and associated digestive glands. Food and
feeding habits of commercially important fishes. Qualitative and quantitative methods of
analysis of gut contents. Circulatory system, respiratory system, nervous system, urino-genital
system, endocrine system, skeletal systems and sensory organs. Reproductive biology –
maturity stages, gonado-somatic index, ponderal index, fecundity, sex ratio and spawning.
Eggs and larval stages and developmental biology. Age and growth determination by direct
and indirect methods. Fish migration - type and significance. Tagging and marking.
Practicals: Study of internal organs – digestive, respiratory, circulatory, urino-genital system,
nervous, skeletal systems and endocrine system. Study of food and feeding habits. Analysis of
gut contents. Estimation of age and growth by direct and indirect methods. Classification of
maturity stages. Estimation of fecundity. Study of developmental stages. Tagging and marking

Session Plan

Session 1

Internal anatomy of Fin Fish
• Introduction to anatomy
• Functions of different internal organs
• Positions of different internal organs
• Integument of Fish
• Function skin or Integument
• Histology
• Epidermis
• Dermis and other cells found in skin ( mucus cell, club cell/ giant cell, sacci form cell)

Session 1 Internal Anatomy


Session 2

Practical : Study of external morphology of finishes

External morphology

Session 3

Scales and fins of fishes
• Different kinds of scales
• Placoid scales: origin and structure
• Non placoid scales (Cosmoid, Ganoid, cycloid and ctenoid type): Origin and structure
• Types of fin
• Paired fins and unpaired fins, structure and function of fins

Practical : Dissection of a bony fish to study different internal organs
Session 2 Scales of fishes

Session 4

Practical : Dissection of a bony fish to study different internal organs

fish dissection

Session 5

Digestive system and associated digestive glands of teleost
• Structure and function of Mouth, Pharynx, Oesophagus, Stomach, Intestine, Pyloric
caeca, Rectum, Anus.
• Histology of different parts of alimentary canal (Buccopharynx, Oesophagus,
Stomach, Intestine and Rectum)
• Structure and function of Liver, gall bladder and pancrease
• Histology of Alimentary canal

 Digestive system

Digestive system

Session 6

Practical: Dissection of a bony fish to study digestive system
Digestive system

Session 7

Oral region and Associated structures
• Structure and function of Oral region and Associated structures
• Oral adaptation for feeding
• Modifications in the lips, mouth, buccopharynx (types of teeth, dentition pattern, gill
rackers), taste buds and associated structures, oesophagus, stomach and intestine

Session 4.Oral region and associated structure

Session 8

Food and feeding habits of fish
• Categories of food (Plankton, Nekton, Benthos, Detritus)
• Classification of food based on its importance (Main or basic food, Occasional or
secondary food, Incidental food, Emergency or obligatory food)
• Different categories of fish based on their feeding habits (Depending on food type:
Monophagic, Stenophagic, Euryphagic; Depending on trophic niches: Surface
feeder, column feeder, bottom feeder; Depending on food preference: Herbivore,
Carnivore, Omnivore, plankton feeder)
Major fish feeding types
• Predators
• Grazers
• Strainers
• Food suckers
• Parasites

Session 5 Food and feeding habits

Feeding habits

Session 9

Feeding periodicity and variation in fishes
• Season
• Migratory cycle and reproductive activity
• Amount of food consumed daily, quantity of food and size of fish
• Food and feeding habits of some commercially important fin fishes

Feeding periodicity and variation in fishes

Session 10

Practical: Study of food and feeding habits of Finfishes

Food and feeding habits

Session 11

Gut content analysis in fishes
• Limitations of gut content analysis
• Separation of gut content
• Feeding Intensity.
Methods of Gut content analysis
• Qualitative method
• Quantitative method: Numerical methods (Occurrence method, Number method,
• Dominance method and Point method), Volumetric method (volume displacement
• method, eye estimation method and Point method) and gravimetric method.
• Indices of gut content analysis

Session 7 Gut content analysisGut content analysis

Session 12

Practical: Qualitative and Quantitative analysis of Gut contents

Gut content analysis

Session 13

Respiratory system in fishes
• Gills as the major site for gas exchange
• Structure of gills
• Holobranch and hemi branch
• Gill arch
• Gill racker
• Gill filament (Primary gill lamellae)
• Gill lamellae (secondary gill lamellae)
• Pseudobranch
Other organs involved in respiration
• Skin
• Alimentary canal
• Air bladder
• Buccopharynx
• Accessory respiratory organs
• Gas bladder or Air bladder
• Physostomus and Physoclistus fish

Session 9 .respiratory system

Session 9.1 Respiratory system continuation

Session 14

Practical: Dissection of a bony fish to study the respiratory system

respiratory system

Session 9.1 Respiratory system continuation

Session 15

Circulatory System of teleost
• Introduction
• Heart of a teleost: Structure and function of different parts
• Modifications in different species
• Working of the teleostean: afferent branchial vessels, efferent branchial vessels,
dorsal aorta and its branches, variations in different species with respect to arterial
• Venous system in fish
• Circulatory system of Scoliodon
• Structure of heart
• Difference between teleostean and elasmobranch heart

Session 8 Circulatory system

Fish circulatory system

Session 16

Practical: Dissection of a bony fish to study the circulatory system

Fish circulatory system

Session 17

Nervous system in fishes
• Cerebrospinal nervous system
• Brain
• Spinal cord
• Structure of Brain: Prosencephalon (Telencephalon and diencephalon),
mesencephalon (optic lobe) and Rhombencephalon(metencephalon and
• Structure of spinal cord
• Peripheral nervous system
• Spinal nerves

Session 10.Nervous system

Nervous system rohu

Session 18

Practicals: Study of Nervous systems of Finfishes

Session 10.Nervous system

Nervous system rohu

Session 19

Urino-genetial system
• Excretory System
• Structure and histology of kidney
• Types of kidney (Type I, II, III, IV and V)
• Structure and function of nephron
• Difference between nephron of fresh water and marine fishes
Session 11 Urino genital system


Session 20

Reproduction in Fishes
• Types of reproduction
• Sexual characters in fishes
• Sexual dimorphism
• Sexual differentiation in fish
Male Reproductive system
• Structure and histology of testes
• Spermatogenesis
• Spermiogenesis
• Structure of sperm
Female Reproductive System
Session 12 reproductive system

Fish reproduction

Session 21

Endocrine system
• Pituitary gland: Location, structure and function
• Thyroid gland: Location, structure and function
• Interregnal plan: Location, structure and function
• Chromaffin tissue: Location, structure and function
• Corpscles of stannous: Location, structure and function
• Ultimobranchial gland: Location, structure and function
• Pineal organ: Location, structure and function
• Urophysis: Location, structure and function
Session 13 Endocrine system

Endocrine system

Session 22

Skeletal system:
Axial skeleton
• Vertebral column
• Skull
Vertebral column
• Complex vertebrae
• Typical trunk vertebrae
• Pre caudal
• Caudal vertebrae
• Urostyle
• Ribs
• Skull
• Neuro cranium: Occipital region, otic region, orbitotemporal region, nasal or
• ethmoidal region
• Appendicular skeleton
• Pectoral girdle
• Pelvic girdle
• Skeleton of median fins

Session 14 Skeletal System

Skeletal System

Session 23

Sensory System in fishes
• Introduction
• Nares
• Eyes
• Skin organs
• Inner ear
• Lateral line system
sensory system pdf

Sensory system

Session 24

Reproduction in Fishes
Maturity stages of testes (Testicular cycle)
• Early immature / resting phase
• Late immature phase
• Maturing phase
• Mature phase
• Spent phase
Maturity stages of ovary (ovarian cycle)
• Immature phase
• Early maturing phase
• Advanced maturing phase
• Mature/ pre spawning phase
• Spawning phase
• Spent phase

Reproduction and maturity stages

Session 25

17 Fecundity
• Definition
• Methods of estimation of fecundity (Gravimetric method and Volumetric method
• Sex Ratio
• Mating
• Spawning
• Ovulation
• Fertilization
Types of egg
Embryonic and larval development
• Cleavage
• Morula
• Blastula
• Gastrula
• Organogenesis
Larval and post larval development
Reproductive strategy

fecundity and Devolepmental stages

Session 26

Growth in fishes
• Definition
• Growth curve
• Growth rate of fishes
• Absolute growth
• Relative growth
• Linear growth characteristics and growth model (Von Bertalanffy growth function)
• Determination of age
• Length frequency method: Advantages and disadvantages
• Recovery of marked fish
• Interpretation of the layers that are laid down in using hard parts of fish body
(Scales, Opercular bones, Otoliths, vertebrae)

parental care and growth

parental care

Session 27

Fish migration
• What is migration
• Types of migration
• Reasons
• Singinificance of migration
19 Fish migration - type and significance


Session 28

<Marking and tagging
Purpose of marking and tagging
Group marking techniques in fishes
Individual marking techniques
• Internal marking technique (Passive integrated transponder tags)
• External marking technique (t - bar tags, plastic tipped dart tags, stainless steel head
dart tags, body cavity tags, self locking "cinch-up" loop tags, plastic head intramuscular
tags - game fish tag, polyethylene streamer tags & glue-on shellfish tags)
Information to be printed on tags
• Release information
• Recapture information
Necessary qualities of a tag

tagging and marking

Case Studies

Case Studies

Our Main Teachers

    Assistant Professor, PhD School of Fisheries Centurion University of Technology and Management (CUTM) Paralakhemundi- 761211 Odisha, INDIA Mobile: +91 6238 514615 Email: ACADEMIC QUALIFICATIONS Ph.D. in Fish Nutrition and Feed Technology(2020) from Central Institute of Fisheries Education(CIFE-ICAR), Mumbai M.F.Sc.(Master of Fisheries Science) in Fish Nutrition and Feed Technology (2015) from Central Institute […]