Magur fish(Clarias batrachus)

The document discusses the digestive system of fish. It covers the main components and processes of the fish digestive system including the mouth, esophagus, stomach, pancreas, liver, intestines and anus. It describes the different feeding mechanisms used by fish such as filter feeding, ram feeding, suction feeding, and others. It also discusses the enzymes involved in digesting carbohydrates, proteins and lipids. In summary: 1) The digestive system of fish breaks down food through a series of organs from the mouth to the anus. 2) Fish use various feeding mechanisms to ingest food depending on their anatomy and food sources. 3) Digestion involves enzymes that break down carbohydrates,

Characters most useful in identification of fish eggs are the following: (1) egg shape-spherical, ellipsoidal, irregular, or oth- erwise; (2) egg size-fish eggs range in size from 0.5 to 26.0 mm; (3) oil globules-presence or-absence. Identification of Fish Eggs - SWFSCswfsc.noaa.gov › publications Search for: How can you tell a fish egg?

This document discusses estuaries and estuarine fisheries in India. It defines an estuary and notes that India has over 55 estuaries along its eastern and western coasts, totaling approximately 30,000 square kilometers. Several major river systems like the Ganges, Mahanadi, Godavari and Krishna form highly productive estuarine ecosystems. The document examines the fish production and ecology of estuaries like the Hooghly, Krishna, Godavari, Mahanadi, Chilka, Pulicat Lake, and Kerala backwaters. It provides details on fish catches, species diversity, and threats like overfishing in several of India's important estuarine systems.

This document discusses paddy-cum-fish culture as a technique for integrated fish and rice farming. It provides details on the history and development of rice-fish culture, site selection considerations, suitable fish and rice varieties, culture techniques, trench designs, advantages and disadvantages. An economic analysis compares the net return from traditional paddy cultivation versus paddy-cum-fish culture, finding that the integrated system provides over double the income. The conclusion states that rice-fish culture is an innovative system that boosts rice yields, generates additional income from fish, and helps reduce farmer poverty while creating jobs.

This document discusses parasitic diseases of fish. It covers various protozoan parasites like Ichthyophthirius multifilis and Epistylis sp. that can infect fish skin and gills. It also discusses metazoan parasites like monogenean trematodes of the genus Dactylogyrus and Gyrodactylus that attach to fish gills and skin, and nematodes of the genus Contracaecum that can infect fish intestines and other tissues. The life cycles of these parasites are described along with the diseases they can cause in fish like emaciation, decreased growth and survival. Methods for specimen collection and examination for parasites are also outlined.

This document discusses the importance of various physical and chemical parameters of water for successful aquaculture. It outlines key water quality factors like temperature, depth, transparency, and dissolved oxygen levels. Temperature affects fish metabolism and physiology, with high temperatures being lethal. Water depth should be between 1.5 to 3 meters. Transparent water supports higher plankton production and fish growth. Dissolved oxygen, pH, hardness, carbon dioxide, and nutrient levels also impact fish health and pond productivity. Maintaining suitable ranges of these parameters is essential for aquaculture.

Fungal diseases can seriously impact fish populations. Three common fungal diseases are: 1. Saprolegniasis is caused by Saprolegnia fungi and is characterized by cotton-like fungal growths on the skin, gills, or eyes of fish. It can spread rapidly between fish and cause death. 2. Branchiomycosis (gill rot) infects gill tissues and is caused by Branchiomyces fungi. Infected fish have difficulty breathing and their gills may appear red. 3. Ichthyophonosis causes rough skin and white lesions inside the body and is caused by Ichthyophonus fungi. More severe infections result in organ

In aquatic animals such as fish respiration takes place through special respiratory organs called gills, however lung fish respiration takes place through lungs. Gills are present on both the sides of the head of fish. The gills are covered by gill covers also called operculum. When the fish open its mouth, water is drawn into the buccal cavity and passed through the gills. The gills contain special type of cells that absorb the oxygen present in water. The absorbed oxygen is then supplied to all the cells of body through blood. In the cells, oxygen is converted into carbon dioxide and returned back to gills through blood. Ultimately, the gills release the carbon dioxide in water passing through them. Respiration in Fish The gills of fish are very efficient; it is estimated gills can extract about 80% oxygen dissolved in water. In addition to the respiratory organs, the gills have an important role in maintaining the right balance of salts in the body.

Fertilized fish eggs are known as Fish seeds. In simple words, they are the baby fishes used for seeding new Ponds in fisheries. Fish seed transportation is a process by which transfer of fish seed from the hatchery or place of collection to the rearing ponds.

All the freshwater prawns that have been cultured so far belong to the genus Macrobrachium , Bate 1868, the largest genus of the family Palaemonidae. About 200 species have been described, almost all of which live in freshwater at least for part of their life. The giant river prawn, Macrobrachium rosenbergii , was one of the first species to become scientifically known , the first recognizable illustration appearing in 1705. The nomenclature of freshwater prawns, both on a generic and a species level has had quite a muddled history. In the past, generic names have included Cancer (Astacus) and Palaemon. Previous names of M. rosenbergii have included Palaemon carcinus, P. dacqueti and P. rosenbergii ( De Man 1879) became universally accepted.

This document discusses the management of nursery ponds for fish culture. It describes the pre-stocking, stocking, and post-stocking management of nursery ponds. For pre-stocking management, it discusses dewatering and drying the pond, desilting, controlling predators and weeds, liming, fertilizing, and maintaining water quality. Nursery ponds are typically stocked at 5-6 million spawn per hectare. Post-stocking management includes feeding the spawn based on their growth and harvesting fry after 15 days once they reach 20-25mm in size. The goal of nursery pond management is to nurse the hatchlings until they grow into fry that can be transferred

Rivers were the major source of freshwater fish seed in India during 1950’s and 1960’s.  Over the years, the riverine contribution has declined and at present forms only a supplementary source, constituting less than 5% of the country’s total fish seed production.  The Ganga, the Brahmaputra and the Indus river systems in the North and the Peninsular East coast and the West coast river systems in the South are the important natural sources of fish seed.