1) Gynogenesis is a form of reproduction that produces all-female offspring through inactivating sperm so it does not contribute genetically.
2) It occurs naturally in some fish and nematode species, and can be induced in others through techniques like irradiating sperm or shocking eggs.
3) Shocking eggs with temperature, pressure, or chemicals can induce polyploidy, resulting in haploid, triploid, or tetraploid offspring useful for aquaculture.
A fish hatchery is a facility where fish eggs are hatched and fish are reared through early life stages. Hatcheries provide fish seed for aquaculture and some fisheries by spawning, hatching, and caring for various fish and shellfish species. Factors to be considered in hatchery design include site selection, water supply and disposal systems, equipment selection, and developing floor plans. Tanks can be circular or rectangular and are used for rearing fish at different life stages.
This document discusses the feeding habits of fish. It begins by defining feeding habit as the kind of food an animal habitually consumes during its life or at a particular stage. It then describes different modes of feeding such as herbivores, omnivores, carnivores, and limnivores. The document highlights that understanding the feeding habits of fish is important for polyculture systems. It also discusses the major types of feeding like grazing, predation, straining, sucking, and parasitism. Finally, it provides examples of different mouth structures in fish and how they relate to the fish's diet.
This document discusses biological productivity in water bodies. It defines biological productivity as the rate of energy production or flow, and explains that it must be considered when selecting sites for culturing organisms, as it indicates the water quality and production potential. The document then provides background on ecosystems and their components, habitats and ecological niches. It describes food chains and trophic structure in aquatic systems. Finally, it defines and compares different measures of productivity, including gross primary productivity, net primary productivity, secondary productivity, and methods for measuring productivity like harvest methods, oxygen measurement, diel changes in oxygen, and radioactive carbon labeling.
Bundhs are tanks or impoundments that simulate riverine conditions for carp breeding during monsoon months. Dry bundhs are seasonal while wet bundhs are perennial. Dry bundhs, popular in West Bengal and Madhya Pradesh, consist of storage ponds, hatcheries, and sluice gates for draining water to allow multiple spawnings per season. Wet bundhs in West Bengal are larger ponds that fill with monsoon rainfall, providing a single annual spawning opportunity. Both bundh types provide controlled environments to induce carp breeding through water level manipulation.
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.
Ornamental fish culture provides opportunities for entrepreneurship and income generation. It requires a minimum of 500 sq ft of land and access to fresh water and electricity. Selection of quality broodstock is important, as different species prefer different water parameters for breeding. Beginners should start with livebearers like guppies and later move to egg-layers, focusing on one species at a time. CIFA has developed technologies for breeding 16 indigenous ornamental fish species and commercializing an endangered species. It conducts national training programs and facilitates entrepreneurs with business plans and information on government subsidies.
This document discusses sewage-fed fish culture, which involves using treated sewage water to culture fish. It provides background on the history and present status of sewage-fed fish culture. The key processes involved are primary and secondary sewage treatment through sedimentation, dilution, and storage before releasing into fish ponds. Farmers culture various fish species using techniques like pond preparation, primary fertilization through sewage, stocking, feeding, and harvesting fish for market. While sewage-fed culture benefits waste recycling and low input costs, it can also pose health risks if not properly managed.
1) Gynogenesis is a form of reproduction that produces all-female offspring through inactivating sperm so it does not contribute genetically.
2) It occurs naturally in some fish and nematode species, and can be induced in others through techniques like irradiating sperm or shocking eggs.
3) Shocking eggs with temperature, pressure, or chemicals can induce polyploidy, resulting in haploid, triploid, or tetraploid offspring useful for aquaculture.
A fish hatchery is a facility where fish eggs are hatched and fish are reared through early life stages. Hatcheries provide fish seed for aquaculture and some fisheries by spawning, hatching, and caring for various fish and shellfish species. Factors to be considered in hatchery design include site selection, water supply and disposal systems, equipment selection, and developing floor plans. Tanks can be circular or rectangular and are used for rearing fish at different life stages.
This document discusses the feeding habits of fish. It begins by defining feeding habit as the kind of food an animal habitually consumes during its life or at a particular stage. It then describes different modes of feeding such as herbivores, omnivores, carnivores, and limnivores. The document highlights that understanding the feeding habits of fish is important for polyculture systems. It also discusses the major types of feeding like grazing, predation, straining, sucking, and parasitism. Finally, it provides examples of different mouth structures in fish and how they relate to the fish's diet.
This document discusses biological productivity in water bodies. It defines biological productivity as the rate of energy production or flow, and explains that it must be considered when selecting sites for culturing organisms, as it indicates the water quality and production potential. The document then provides background on ecosystems and their components, habitats and ecological niches. It describes food chains and trophic structure in aquatic systems. Finally, it defines and compares different measures of productivity, including gross primary productivity, net primary productivity, secondary productivity, and methods for measuring productivity like harvest methods, oxygen measurement, diel changes in oxygen, and radioactive carbon labeling.
Bundhs are tanks or impoundments that simulate riverine conditions for carp breeding during monsoon months. Dry bundhs are seasonal while wet bundhs are perennial. Dry bundhs, popular in West Bengal and Madhya Pradesh, consist of storage ponds, hatcheries, and sluice gates for draining water to allow multiple spawnings per season. Wet bundhs in West Bengal are larger ponds that fill with monsoon rainfall, providing a single annual spawning opportunity. Both bundh types provide controlled environments to induce carp breeding through water level manipulation.
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.
Ornamental fish culture provides opportunities for entrepreneurship and income generation. It requires a minimum of 500 sq ft of land and access to fresh water and electricity. Selection of quality broodstock is important, as different species prefer different water parameters for breeding. Beginners should start with livebearers like guppies and later move to egg-layers, focusing on one species at a time. CIFA has developed technologies for breeding 16 indigenous ornamental fish species and commercializing an endangered species. It conducts national training programs and facilitates entrepreneurs with business plans and information on government subsidies.
This document discusses sewage-fed fish culture, which involves using treated sewage water to culture fish. It provides background on the history and present status of sewage-fed fish culture. The key processes involved are primary and secondary sewage treatment through sedimentation, dilution, and storage before releasing into fish ponds. Farmers culture various fish species using techniques like pond preparation, primary fertilization through sewage, stocking, feeding, and harvesting fish for market. While sewage-fed culture benefits waste recycling and low input costs, it can also pose health risks if not properly managed.
This document discusses coloration in fishes. It begins by introducing the sources of color - chromatophores and iridiophores. Chromatophores contain pigment cells called melanophores, erythrophores, xanthophores, and iridiophores which produce black/brown, red/orange, yellow, and white colors respectively. Fishes obtain varied color patterns through mixing of these pigments. Chromatophores can respond physiologically through pigment redistribution or morphologically by changing cell number or pigment amount. Coloration allows for camouflage through concealment, disguise, and advertisement behaviors which aid communication, survival, and reproduction.
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.
This document discusses sex reversal in fish through hormone treatment. It explains that in early development, gonads can differentiate into either testes or ovaries, and hormones guide this process. Sex reversal has been achieved by turning males into females and vice versa. Temperature and hormone treatments before phenotypic sex development can cause total functional sex reversal. The document outlines different hormone treatment methods, examples of steroid hormones used, and considerations for successful and sustainable sex reversal programs.
This document provides an overview of reproductive biology in fishes. It discusses the different types of sexuality observed in fishes, including unisexuality, bisexuality, hermaphroditism, and parthenogenesis. It describes the reproductive cycles and hormones that regulate reproduction for both male and female fish. Key aspects covered include the gonads, sexual dimorphism, seasonal breeding patterns, and hormonal control of the reproductive system through the CNS-pituitary-gonad axis.
Pen culture involves holding culturable aquatic organisms in enclosed spaces surrounded by nets or fences while maintaining water flow. It originated in Asia in the early 1920s and was later introduced to freshwater lakes and reservoirs. Pens are usually built in shallow waters and consist of barriers made from various materials like concrete, wire mesh, or nylon nets. Common species cultured in pens include various carp, milkfish, tilapia, and prawns. While pen culture provides benefits like increased production and growth, it also faces challenges like damage from predators, fouling, and poor harvest recovery rates. Overall, pen culture is best suited for extensive or semi-intensive aquaculture.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
This document discusses fertilization of fish ponds. It explains that fertilization increases essential nutrients which leads to increased productivity. It causes algal blooms that provide shade and prevent weed growth. Fertilizers are substances that increase natural food for fish. Organic fertilizers are cheaper and provide nutrients slowly while inorganics are more concentrated but must be carefully applied. The primary purpose of fertilization is to boost nutrients and productivity in fish ponds, but over-fertilization can deplete oxygen and harm fish. Proper scheduled application of fertilizers is important.
Generalized and specific definition of pond and the types relating their size, use, construction method were illustrated. Besides the culture system of fish and aquatic organisms and their types were also described.
This document discusses the classification of planktonic organisms. It defines plankton as diverse microscopic and small organisms that live in water bodies but cannot swim against currents. Plankton are classified into phytoplankton and zooplankton. Phytoplankton include algae and cyanobacteria that photosynthesize, while zooplankton feed on other plankton. Both groups are further divided based on size into bacterio, nano, micro, macro, and meg plankton. The document provides examples for different classifications.
This document summarizes information about brackishwater aquaculture in India. It discusses how brackishwater aquaculture contributes to India's GDP and agricultural GDP. Farmed shrimp production reached 7 lakh tonnes in 2019, with 87% exported earning Rs. 3500 crores. India has vast coastal and inland resources suitable for brackishwater aquaculture. Common species cultured are Penaeus monodon and Litopenaeus vannamei. The document outlines considerations for site selection, pond design and construction, stocking, feeding, and harvesting practices. It also discusses disease prevention and management techniques.
Hybridization is the act of breeding between two different fish species or genera that do not ordinarily interbreed. There are two types: natural hybridization which can occur when species spawn in the same area due to habitat changes, and artificial hybridization where gametes are manually mixed. This results in a hybrid offspring that has intermediate physical characteristics between the parents. Examples include hybrids of different carp species. Hybrids can be diploid or polyploid depending on chromosome manipulation techniques used. While hybridization may have economic benefits, uncontrolled hybridization could cause losses.
Pond Design And Construction System In An Aqua Farm.AsrafurTalha1
This document outlines the pond design and construction system for an aqua farm. It discusses selecting a suitable site based on soil type, water source, and topography. Different types of ponds are described for nursery, rearing, stocking, and treatment purposes. The construction process involves preparing the site, building dikes and clay cores, digging the pond, and installing inlets and outlets. Material used, fencing, and planting vegetation on dikes is also covered. Proper pond design and construction is essential for a successful fish farming operation.
Setting an aquarium is an important steps to maintaining healthy ornamental fishes. It gives mind relaxation and peaceful. It is a hobby and reduces the stress also
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,
Soil is an important ecological factor for aquatic environments and ponds. It is the main source of nutrients through decomposition of detritus by microbes like algae and bacteria. This enhances pond productivity and supports bottom-dwelling organisms that fish prey on. Key soil properties that influence suitability for fish culture include pH, organic carbon, phosphorus and nitrogen levels, carbon to nitrogen ratio, texture and water holding capacity. Optimal ranges are pH of 6.5-7.5, over 1% organic carbon, phosphorus and nitrogen above 10 mg/100g and 6 mg/100g respectively, and a carbon to nitrogen ratio of 10-15.
1. Plankton are microscopic or macroscopic aquatic organisms that drift or float in freshwater and marine environments. They are divided into phytoplankton, which are autotrophic plant-like organisms, and zooplankton, which are heterotrophic animal-like organisms.
2. Phytoplankton include algae, diatoms, and dinoflagellates that form the base of aquatic food chains. Zooplankton feed on phytoplankton and include crustaceans like copepods and cladocerans.
3. Polyculture is the practice of culturing multiple fish species together in a pond by selecting species with different feeding habits, from
This document discusses fish nutrition and feed technology. It covers fundamentals of fish nutrition including the importance of proper nutrition for fish farming. Fish require proteins, lipids, carbohydrates, vitamins and minerals for healthy growth. Energy is also essential and is derived from dietary nutrients. The document outlines various forms of energy partitioning in fish and methods of energy metabolism. It discusses laws of thermodynamics and units of energy measurement. Feed formulation involves balancing protein, energy and amino acid levels. The steps in feed formulation include initial protein and energy balancing, checking indispensable amino acid levels, and consideration of additives.
EUS is an infection of freshwater and estuarine fish caused by the oomycete fungi Aphanomyces invadans. It is an epizootic disease affecting many fish in an area simultaneously. EUS causes ulceration of the skin and erosion of tissue, particularly on the tail and head. Advanced cases show necrosis in internal organs. Control involves stopping water flow, removing infected fish, applying lime or calcium hydroxide to raise pH, and introducing fresh water after 3 weeks. CIFA has also developed a medicine called CIFAX to treat and prevent EUS.
1. Induced breeding is a technique where ripe fish are stimulated to breed in captivity using pituitary hormones or synthetic hormones.
2. The history of induced breeding began in the 1930s in Argentina and Brazil, and was first applied to Indian major carps like Cirrhinus mrigala in the late 1930s.
3. Induced breeding is needed because environmental conditions and hormone levels may be insufficient to trigger natural spawning in captive conditions.
Plankton are microscopic organisms that drift or float in aquatic environments. They are categorized into phytoplankton and zooplankton. Phytoplankton are plant-like organisms that can photosynthesize, while zooplankton are animal plankton that consume other organisms. Plankton play important roles in aquatic ecosystems as indicators of water quality, primary producers that form the base of the food web, producers of oxygen through photosynthesis, and major participants in the global carbon cycle. They are studied and classified by size, nutritional requirements, length of planktonic life, and habitat. Understanding plankton communities provides insights into ecosystem health and functions.
This document describes the different types of eggs based on the amount and distribution of yolk. There are three main types: microlecithal eggs with very small amounts of yolk, mesolecithal eggs with moderate amounts, and megalecithal eggs with enormous amounts. The distribution of yolk also varies, with some eggs having evenly distributed yolk (homolecithal) and others having polarized yolk concentrated in one hemisphere (telolecithal). Egg membranes form inside and outside the ovary, providing protection, buoyancy, and preventing self-fertilization. Unequal cytokinesis during meiosis allows one cell to contain most of the yolk to sufficiently nourish the developing embryo.
The document discusses the egg and larval development of fish from fertilization through the various life stages until adulthood. It describes the embryonic, larval, fry, ripe, and senescent phases. During the embryonic phase, development occurs inside the egg until hatching. The larval phase follows, where the yolk sac is absorbed and organs develop. Next is the fry phase where scales develop. The ripe phase occurs when gonads are fully developed. Finally, the senescent phase is when sexual activity declines. The document also covers reproductive cycles, environmental cues for spawning, and methods for assessing fish recruitment.
This document discusses coloration in fishes. It begins by introducing the sources of color - chromatophores and iridiophores. Chromatophores contain pigment cells called melanophores, erythrophores, xanthophores, and iridiophores which produce black/brown, red/orange, yellow, and white colors respectively. Fishes obtain varied color patterns through mixing of these pigments. Chromatophores can respond physiologically through pigment redistribution or morphologically by changing cell number or pigment amount. Coloration allows for camouflage through concealment, disguise, and advertisement behaviors which aid communication, survival, and reproduction.
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.
This document discusses sex reversal in fish through hormone treatment. It explains that in early development, gonads can differentiate into either testes or ovaries, and hormones guide this process. Sex reversal has been achieved by turning males into females and vice versa. Temperature and hormone treatments before phenotypic sex development can cause total functional sex reversal. The document outlines different hormone treatment methods, examples of steroid hormones used, and considerations for successful and sustainable sex reversal programs.
This document provides an overview of reproductive biology in fishes. It discusses the different types of sexuality observed in fishes, including unisexuality, bisexuality, hermaphroditism, and parthenogenesis. It describes the reproductive cycles and hormones that regulate reproduction for both male and female fish. Key aspects covered include the gonads, sexual dimorphism, seasonal breeding patterns, and hormonal control of the reproductive system through the CNS-pituitary-gonad axis.
Pen culture involves holding culturable aquatic organisms in enclosed spaces surrounded by nets or fences while maintaining water flow. It originated in Asia in the early 1920s and was later introduced to freshwater lakes and reservoirs. Pens are usually built in shallow waters and consist of barriers made from various materials like concrete, wire mesh, or nylon nets. Common species cultured in pens include various carp, milkfish, tilapia, and prawns. While pen culture provides benefits like increased production and growth, it also faces challenges like damage from predators, fouling, and poor harvest recovery rates. Overall, pen culture is best suited for extensive or semi-intensive aquaculture.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
This document discusses fertilization of fish ponds. It explains that fertilization increases essential nutrients which leads to increased productivity. It causes algal blooms that provide shade and prevent weed growth. Fertilizers are substances that increase natural food for fish. Organic fertilizers are cheaper and provide nutrients slowly while inorganics are more concentrated but must be carefully applied. The primary purpose of fertilization is to boost nutrients and productivity in fish ponds, but over-fertilization can deplete oxygen and harm fish. Proper scheduled application of fertilizers is important.
Generalized and specific definition of pond and the types relating their size, use, construction method were illustrated. Besides the culture system of fish and aquatic organisms and their types were also described.
This document discusses the classification of planktonic organisms. It defines plankton as diverse microscopic and small organisms that live in water bodies but cannot swim against currents. Plankton are classified into phytoplankton and zooplankton. Phytoplankton include algae and cyanobacteria that photosynthesize, while zooplankton feed on other plankton. Both groups are further divided based on size into bacterio, nano, micro, macro, and meg plankton. The document provides examples for different classifications.
This document summarizes information about brackishwater aquaculture in India. It discusses how brackishwater aquaculture contributes to India's GDP and agricultural GDP. Farmed shrimp production reached 7 lakh tonnes in 2019, with 87% exported earning Rs. 3500 crores. India has vast coastal and inland resources suitable for brackishwater aquaculture. Common species cultured are Penaeus monodon and Litopenaeus vannamei. The document outlines considerations for site selection, pond design and construction, stocking, feeding, and harvesting practices. It also discusses disease prevention and management techniques.
Hybridization is the act of breeding between two different fish species or genera that do not ordinarily interbreed. There are two types: natural hybridization which can occur when species spawn in the same area due to habitat changes, and artificial hybridization where gametes are manually mixed. This results in a hybrid offspring that has intermediate physical characteristics between the parents. Examples include hybrids of different carp species. Hybrids can be diploid or polyploid depending on chromosome manipulation techniques used. While hybridization may have economic benefits, uncontrolled hybridization could cause losses.
Pond Design And Construction System In An Aqua Farm.AsrafurTalha1
This document outlines the pond design and construction system for an aqua farm. It discusses selecting a suitable site based on soil type, water source, and topography. Different types of ponds are described for nursery, rearing, stocking, and treatment purposes. The construction process involves preparing the site, building dikes and clay cores, digging the pond, and installing inlets and outlets. Material used, fencing, and planting vegetation on dikes is also covered. Proper pond design and construction is essential for a successful fish farming operation.
Setting an aquarium is an important steps to maintaining healthy ornamental fishes. It gives mind relaxation and peaceful. It is a hobby and reduces the stress also
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,
Soil is an important ecological factor for aquatic environments and ponds. It is the main source of nutrients through decomposition of detritus by microbes like algae and bacteria. This enhances pond productivity and supports bottom-dwelling organisms that fish prey on. Key soil properties that influence suitability for fish culture include pH, organic carbon, phosphorus and nitrogen levels, carbon to nitrogen ratio, texture and water holding capacity. Optimal ranges are pH of 6.5-7.5, over 1% organic carbon, phosphorus and nitrogen above 10 mg/100g and 6 mg/100g respectively, and a carbon to nitrogen ratio of 10-15.
1. Plankton are microscopic or macroscopic aquatic organisms that drift or float in freshwater and marine environments. They are divided into phytoplankton, which are autotrophic plant-like organisms, and zooplankton, which are heterotrophic animal-like organisms.
2. Phytoplankton include algae, diatoms, and dinoflagellates that form the base of aquatic food chains. Zooplankton feed on phytoplankton and include crustaceans like copepods and cladocerans.
3. Polyculture is the practice of culturing multiple fish species together in a pond by selecting species with different feeding habits, from
This document discusses fish nutrition and feed technology. It covers fundamentals of fish nutrition including the importance of proper nutrition for fish farming. Fish require proteins, lipids, carbohydrates, vitamins and minerals for healthy growth. Energy is also essential and is derived from dietary nutrients. The document outlines various forms of energy partitioning in fish and methods of energy metabolism. It discusses laws of thermodynamics and units of energy measurement. Feed formulation involves balancing protein, energy and amino acid levels. The steps in feed formulation include initial protein and energy balancing, checking indispensable amino acid levels, and consideration of additives.
EUS is an infection of freshwater and estuarine fish caused by the oomycete fungi Aphanomyces invadans. It is an epizootic disease affecting many fish in an area simultaneously. EUS causes ulceration of the skin and erosion of tissue, particularly on the tail and head. Advanced cases show necrosis in internal organs. Control involves stopping water flow, removing infected fish, applying lime or calcium hydroxide to raise pH, and introducing fresh water after 3 weeks. CIFA has also developed a medicine called CIFAX to treat and prevent EUS.
1. Induced breeding is a technique where ripe fish are stimulated to breed in captivity using pituitary hormones or synthetic hormones.
2. The history of induced breeding began in the 1930s in Argentina and Brazil, and was first applied to Indian major carps like Cirrhinus mrigala in the late 1930s.
3. Induced breeding is needed because environmental conditions and hormone levels may be insufficient to trigger natural spawning in captive conditions.
Plankton are microscopic organisms that drift or float in aquatic environments. They are categorized into phytoplankton and zooplankton. Phytoplankton are plant-like organisms that can photosynthesize, while zooplankton are animal plankton that consume other organisms. Plankton play important roles in aquatic ecosystems as indicators of water quality, primary producers that form the base of the food web, producers of oxygen through photosynthesis, and major participants in the global carbon cycle. They are studied and classified by size, nutritional requirements, length of planktonic life, and habitat. Understanding plankton communities provides insights into ecosystem health and functions.
This document describes the different types of eggs based on the amount and distribution of yolk. There are three main types: microlecithal eggs with very small amounts of yolk, mesolecithal eggs with moderate amounts, and megalecithal eggs with enormous amounts. The distribution of yolk also varies, with some eggs having evenly distributed yolk (homolecithal) and others having polarized yolk concentrated in one hemisphere (telolecithal). Egg membranes form inside and outside the ovary, providing protection, buoyancy, and preventing self-fertilization. Unequal cytokinesis during meiosis allows one cell to contain most of the yolk to sufficiently nourish the developing embryo.
The document discusses the egg and larval development of fish from fertilization through the various life stages until adulthood. It describes the embryonic, larval, fry, ripe, and senescent phases. During the embryonic phase, development occurs inside the egg until hatching. The larval phase follows, where the yolk sac is absorbed and organs develop. Next is the fry phase where scales develop. The ripe phase occurs when gonads are fully developed. Finally, the senescent phase is when sexual activity declines. The document also covers reproductive cycles, environmental cues for spawning, and methods for assessing fish recruitment.
Fertilization is a complex chain of events that must occur successfully for conception. It begins with changes to the sperm to prepare for fusion with an egg. A single sperm must fuse with the egg to prevent polyspermy, which leads to embryonic death. Following fusion, the genetic material from the sperm and egg combine and the zygote undergoes rapid cell division through cleavage to form a blastula or blastocyst. This initiates differentiation of cells and early embryonic development.
- Gametogenesis is the production of gametes (sex cells) via meiosis from germ cells. This involves the formation of haploid egg and sperm cells from diploid precursor cells.
- Eggs undergo a process called oogenesis to form female gametes (ova/eggs). Sperm undergo spermatogenesis to form male gametes. Both involve mitosis, growth, and meiotic maturation.
- Mature eggs contain stored nutrients, proteins, mRNA and other materials necessary to support early embryonic development before the embryo can feed itself. Eggs accumulate these materials during oogenesis.
1. Embryonic development in insects includes cleavage, blastoderm formation, gastrulation, formation of the germ band and organ systems, and appendages developing from the three germ layers.
2. Post-embryonic development occurs outside the egg and insects progress through instars separated by molts until reaching adulthood.
3. There are four main types of metamorphosis in insects - ametabola (no change), hemimetabola (incomplete change), paurometabola (gradual change), and holometabola (complete change through a larval stage and pupal stage).
presentation on oogenesis of fertilisation process full details about it u will never find it anywhere else have full details about the ovum formation polar bodies and everything . so explore here
Comparative Anatomy of Vertebrates Chapter 5 Early Craniate MorphogenesisLarry Sultiz
This document provides an overview of early craniate morphogenesis and development. It discusses the types of eggs craniates produce (microlecithal, mesolecithal, macrolecithal), cleavage patterns (holoblastic, meroblastic), and developmental stages (gastrulation, neurulation, organogenesis). Key events include the formation of the three germ layers (ectoderm, endoderm, mesoderm) and their contributions to tissues and organs, as well as the roles of the neural crest, placodes and morphogens in differentiation and development.
The document discusses early concepts of development including preformation versus epigenesis. It was once thought that the embryo was preformed in the egg, but experiments demonstrated that undifferentiated material in the egg becomes arranged through epigenesis. Key developmental stages are described including fertilization, cleavage, blastula formation, and gastrulation which establishes the three germ layers. Differences in protostome and deuterostome development are outlined, focusing on differences in cleavage, fate determination, and body axis formation. The role of induction in patterning the embryo is also summarized.
The document summarizes the functional morphology of gonads in fish. It describes the structure and function of testes and ovaries, including their attachment in the body cavity, composition of seminiferous tubules in testes, stages of oocyte maturation in ovaries, and seasonal reproductive cycles involving rhythmic changes in the gonads. Key phases of the testicular and ovarian cycles include resting, preparatory, mature/prespawning, spawning, and post-spawning periods characterized by spermatogenesis, spermiation, and ovulation processes.
The document summarizes key stages in animal embryogenesis including fertilization, cleavage, blastulation, gastrulation, and neurulation. During fertilization, a sperm fuses with an egg to form a zygote. Cleavage involves cell divisions that form a ball of cells or blastula. Gastrulation establishes the three germ layers through cell movements. It occurs differently depending on egg characteristics like yolk content. Neurulation transforms the gastrula into a neurula by forming the neural tube from ectoderm.
Fish reproductive organs include paired testes and ovaries located in the abdominal cavity. Reproduction can involve unisexuality, bisexuality, or hermaphroditism. The testes produce sperm and hormones, while ovaries contain developing oocytes at different stages of maturation. Environmental and nutritional factors influence reproduction. Understanding fish reproductive physiology is important for aquaculture practices like controlled spawning and seed quality improvement.
Journey of an embryo...development biologyakfanazraf90
1. Neurulation and organogenesis are key developmental processes in early embryos. Neurulation involves the formation of the neural plate and tube which give rise to the central nervous system. Organogenesis is when specific organs are formed through cell differentiation and tissue interactions.
2. The three germ layers - endoderm, mesoderm and ectoderm - produce different organ systems. The endoderm forms lung, thyroid and pancreas tissues. The mesoderm aids in heart, muscle, kidney and blood development. The ectoderm produces skin and neural tissues.
3. Embryonic development proceeds through stages of cleavage, gastrulation, neurulation and organogenesis as the single-celled z
Oogenesis is the process by which ova or egg cells are formed in the ovaries. It involves three main phases: 1) the multiplication phase where primordial germ cells undergo mitosis to form oogonia, 2) the growth phase where the oocytes increase in size through protein and RNA synthesis, and 3) the maturation phase where the oocytes undergo the first meiotic division to form secondary oocytes, followed by ovulation and the second meiotic division after fertilization to form the ovum. Key events include cytoplasmic growth through organelle proliferation and yolk deposition, formation of the follicle surrounding the oocyte, and reduction of the chromosome number through meiosis.
Oogenesis is the process by which female gametes (ova/eggs) are formed. It begins during fetal development with the formation of oogonia, which undergo mitosis to form primary oocytes. Primary oocytes then enter meiosis I but arrest in prophase I. After puberty, one oocyte is selected each month to complete meiosis I and II, forming a haploid egg and polar bodies. The remaining oocytes remain arrested until death. Oogenesis involves three phases - multiplication, growth, and maturation - resulting in a mature ovum containing half the number of chromosomes, organelles and nutrients required for embryonic development.
Internal fertilization involves the male releasing sperm into the female reproductive tract, increasing chances of fertilization. After fertilization, the zygote undergoes cleavage and develops into a morula, blastula and gastrula. The gastrula forms the three germ layers - ectoderm, endoderm and mesoderm - which give rise to the organs of animals. In humans, the blastocyst implants in the uterus and develops a placenta and umbilical cord to exchange gases and nutrients with the mother.
The document summarizes the human reproductive system and stages of human growth. It also discusses the reproductive systems of representative animal groups like amphibians, birds, fish, and mammals. Key parts of each system are described along with their functions in reproduction. Differences in external and internal fertilization between groups are also mentioned.
The document summarizes the human reproductive system and stages of human growth. It also discusses the reproductive systems of representative animal groups like amphibians, birds, fish, and mammals. Key parts of the reproductive systems are described for each group, including their functions in producing gametes and supporting development. The modes of reproduction for different animal groups are also compared, such as external vs internal fertilization.
1) Early mammalian embryonic development involves cleavage divisions that result in a solid ball of cells called a morula.
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3. The embryonic phase lasts until 8 weeks when major organ systems have begun to form and it is then called a fetus. By the end of the third month the placenta is functioning to exchange gases, nutrients, and waste
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Eggs and larval dynamics of finfish and shellfish.pptx
1. Eggs and larval dynamics
Prepared by - Sourav Saha
FSM-2022-20-08
M.F.Sc. 1st Year, FRM
2. Reproductive cycle in fish
• Majority of teleost fishes are seasonal breeders, while a few
breed continuously.
• In order that survival of young be optimized, the timing of
spawning by the mature, adult fish must be closely linked to
the cycles of availability of prey consumed by the newly
hatched young.
• In many temperate and cold water species, spawning is an
annual event. These fishes have discrete spawning season, so
that the eggs hatch, and young are ready to consume
exogenous food, at a time when prey is abundant.
3. • In broad terms annual cycle can be divided into three
major periods, or phases:
1. A post-spawning period when the gonads are small
and appear to be in a resting phase;
2. A pre-spawning period in which the gonads begin
production of gametes (gametogenesis) and there is
production and incorporation of yolk into the oocytes
(vitellogenesis); this is accompanied by a gradual
increase in gonad size;
3. A spawning period, involving final maturation and
ripening of the gametes: this phase culminates in the
spawning act, with the release of gametes and
fertilization of the eggs.
4. Photoperiod, temperature and seasonal rainfall, among other factors, are
important in regulating reproductive cycles in teleost fishes. They show
considerable but precisely-timed annual fluctuations in temperate regions,
whereas in the tropics, dry seasons alternate with wet ones and lead to
seasonal differences in water quality and food availability.
In many Salmonids, that spawn in autumn, gradually increasing photoperiods
followed by decreasing ones or even short photoperiods play a dominant role in
the regulation of reproductive cycles.
In Cyprinid and Perciform fishes, temperature may also be a significant
regulatory factor in the reproductive cycling.
Thus, even among teleost fishes, mechanisms for reproductive timing vary
considerably.
5. Embryonic Development in Finfishes
1. Fertilization
Fertilization is usually external in water, and sperms and ova are discharged close to each
other in water. Sperms become very active soon after they are released in water, but
survive only for a few minutes during which fertilization takes place.
Fertilization is internal in a few teleostean species, in which the urinogenital papilla or
the anal fin is enlarged and modified for transferring the sperms.
Key stages in embryonic development:
1. Fertilization
2. Cleavage
3. Blastula formation
4. Gastrulation
5. Hatching and postembryonic
development
6. 2. Cleavage
Cleavage is a period after fertilization, when a 1-cell embryo starts developing into a
multicellular organism.
It consists of a series of mitotic divisions, which divide the large volume of a fertilized egg
into numerous smaller, nucleated cells—blastomeres.
It is meroblastic (incomplete) being confined to the layer of cytoplasm.
In early stages, the cleavage is vertical only and all the cells lie in one plane over the yolk.
Later, horizontal cleavages take place and more than one row of blastomeres are formed.
7. 3. Blastula
A blastula is an early embryonic stage characterized by a hollow, fluid-filled sphere or ball of
cells.
As the zygote undergoes cleavage, it transforms into a multicellular structure with a central
fluid-filled cavity known as the blastocoel.
The key characteristic of the blastula is its hollow, spherical structure. It consists of an outer
layer of cells called the blastoderm, which surrounds the central fluid-filled cavity.
The blastula serves as a stage of development during which the embryo is organized into
distinct cell layers.
The formation of the blastula is a critical step in embryonic development because it marks
the beginning of differentiation and specialization of cells.
8. 3. Gastrulation
During gastrulation, the single-layered blastula transforms into a three-layered structure,
known as the gastrula. This process is essential for the formation of various tissues and
organs in the developing fish embryo.
It results in the formation of three primary germ layers: ectoderm, mesoderm, and
endoderm. These germ layers give rise to different tissues and organs during the later stages
of fish development.
• Ectoderm: The outermost layer that gives rise to the skin, nervous system, and sensory
organs.
• Mesoderm: The middle layer that contributes to muscles, bones, circulatory system, and
reproductive organs.
• Endoderm: The innermost layer that develops into the digestive system and associated
organs.
9. 3. Hatching and Postembryonic development
A small embryo formed having more or less cylindrical, bilaterally symmetrical body.
Body of embryo becomes distinct from yolk sac.
The embryo grows further in size, while yolk sac shrinks.
Finally hatching takes place and embryo become free swimming larvae.
The ectoderm forms the epidermis and its derivatives like enamel of the teeth, lens of eye,
and internal ear. Brain, Spinal cord and retina also formed fro, ectoderm.
The mesoderm divide into epimere, mesomere and hypomere. Epimere divide to form
vertebral column, muscles etc. Mesomere give rise to kidneys, gonads and their ducts.
Hypomere enclose the coelomic cavity.
10. Embryonic Development in Shellfishes
Embryonic development in shellfish, which include various species of mollusks (such as clams, oysters,
and mussels) and crustaceans (like shrimp, crabs, and lobsters), is a complex and highly variable
process. The specific stages and details of embryonic development can differ among different species of
shellfish. Here is a general overview of the stages involved:
1. Fertilization: The first step in embryonic development is the fertilization of eggs by sperm. In some
shellfish, fertilization is external, with eggs and sperm released into the water where fertilization
occurs. In others, it may be internal, with the male transferring sperm to the female.
2. Cleavage: Cleavage patterns can be classified into two main types: holoblastic and meroblastic
cleavage.
i. Holoblastic Cleavage: This type of cleavage occurs when the entire zygote or egg undergoes cleavage.
Bivalve mollusks (e.g., clams and oysters)
11. A. Radial Holoblastic Cleavage: In radial cleavage, the cleavage planes are
perpendicular or parallel to the animal-vegetal axis. This type of cleavage is commonly observed
in echinoderms.
B. Spiral Holoblastic Cleavage: In spiral cleavage, the cleavage planes are diagonal to
the animal-vegetal axis, leading to a distinctive spiral arrangement of cells. Spiral cleavage is more
characteristic of annelids and some mollusks.
ii. Meroblastic Cleavage: In meroblastic cleavage, only a portion of the zygote undergoes
cleavage, typically due to the presence of yolk. This type of cleavage is common in organisms with
large amounts of yolk. Crustaceans (e.g., crabs and shrimp) and cephalopod mollusks (e.g., squids
and octopuses) show meroblastic cleavage.
12. 3. Blastula Formation: The cleavage-stage embryo develops into a blastula,
which is a hollow, fluid-filled sphere of cells. The blastula is the early
embryonic stage that follows cleavage.
4. Gastrulation: Gastrulation is the stage where the blastula undergoes a
reorganization of cells to form three primary germ layers: ectoderm,
mesoderm, and endoderm. These germ layers give rise to different tissues
and organs in the developing shellfish embryo.
5. Organogenesis: Following gastrulation, the embryo continues to develop,
and specific organs and structures start to form. The timing and details of
organogenesis can vary significantly among different species. For instance, in
bivalve mollusks like clams and oysters, the formation of the shell and gills is a
critical part of organogenesis.
13. Spawning stock and recruitment
It is the rate at which individuals recruit to the population that determines how rapidly
the numbers within a disturbed population will return to the equilibrium level.
Density-
dependent
factors
The absolute
numbers of fish
recruiting to the
population
influenced by
Population density
Spawning stock
Density dependent
factors related to
amount of food available
to individuals
Individual fecundity
Even when the individual fecundity is reduced, the population fecundity
may be higher for a large spawning stock.
14. The population fecundity gives an indication of the potential numbers of
recruits immediately after spawning (N0).
The eggs and larvae are vulnerable to predation, and mortality rate (M)
may be relatively high, so that there is a relatively rapid decline in
numbers with time.
The change in numbers with time (D in days) may be described by -
where ND is the number of eggs or
larvae remaining after time D days
ND = N0 e-MD
When initial number (N0) are large, the newly hatched larvae may deplete
their food base and, consequently, individual growth rate may be low. Slow
growing larvae need more time to reach the size of metamorphosis
(recruitment), therefore, vulnerable to predation for a longer period of time.
15. There are mainly two theories about relation between spawning stock and
recruitment:
The Beverton-Holt model, which says that the recruitment increases with the
size of the spawning stock to a certain level, then it flattens out. Further
increase of the spawning stock does not lead to higher recruitment.
Then we have the Ricker model, recruitment increases with the size of the
spawning stock to a maximum, then recruitment decreases as the spawning
stock increases.
Stock-recruitment relationship
There may be fewer recruits to the
population when the spawning
stock is large than when it is small.
16. How Recruitment Fits in Fish Life Cycles
The fish life cycle can be broken up into several notable physical stages,
in each of which mortality can be described as density-dependent or
density-independent.
Mortality for egg and larval stages is often considered density-
independent because these tiny fish have less control over the habitats
they occupy compared to larger fish.
Once larval fish have developed enough to direct themselves, they
often settle into structural habitat (like aquatic vegetation, corals,
shallow areas, etc.) or aggregate into schools. This settlement phase is
when most scientists think mortality begins to be density-dependent,
and the recruitment period starts.
Eventually the fish will grow large enough that density-dependent
mortality ceases and the fish are considered
as recruited or recruit size.
17. all larval fish must still survive the density-dependent period to become a
recruit. For this reason, recruitment is sometimes referred to as a "bottleneck"
because it limits the number of fish surviving to larger sizes where they can be
caught by fishers and eventually spawn to replenish the population.
18. Environmental cues
Environmental cues are subtle signals in the physical environment that influence
behavior, emotions and decisions of an organism.
Different fish species have been found to use different environmental cues to
time their reproductive migration, such as photoperiod, temperature, discharge,
hour in a day, lunar cycle, atmospheric pressure, or precipitation.
gonadal maturation
and reproductive
migrations
linked to
Photoperiod
Temperature
variation
19. Temperature: Water temperature plays a critical role in fish reproduction. Many fish
species have specific temperature ranges at which they spawn. Warmer temperatures
often trigger the onset of spawning, while cooler temperatures can delay or inhibit it.
Proper temperature is also essential for the development and survival of fish eggs and
larvae.
Photoperiod: The length of daylight hours, or photoperiod, can signal the appropriate
time for fish to reproduce. Changes in day length with the seasons can trigger
spawning behavior in many species. Some fish, like salmon, rely heavily on
photoperiod cues to determine when and where to spawn.
Food Availability: The availability of prey organisms is crucial for the survival of fish
larvae. Fish often time their spawning to coincide with periods of increased food
availability, such as the hatching of planktonic organisms. Adequate food resources are
necessary for the growth and survival of larval fish.
20. Water Flow and Currents: Water flow and currents can help disperse fish eggs and
larvae, increasing their chances of survival. Some species rely on specific water flow
patterns to transport their offspring to suitable nursery areas.
Oxygen Levels: Adequate oxygen levels are essential for fish egg development and
larval survival. Poor water quality, with low oxygen levels, can be detrimental to fish
reproduction and early life stages.
Salinity: For fish that inhabit estuaries and coastal areas, changes in salinity can be an
important cue. Some species require specific salinity levels for successful reproduction
and larval development. For example, many euryhaline species need lower salinities
for egg fertilization and larval survival.
21. Predator Avoidance: Avoiding predators is essential for the survival of fish eggs and
larvae. Many fish species time their spawning to minimize exposure to predators, often
choosing nighttime or low-light conditions.
Social Interactions: In some species, social interactions among individuals can
influence the timing of reproduction. Hierarchies within fish populations may
determine which individuals get to spawn first.
Chemical Signals: Chemical cues, such as pheromones released by adult fish, can play a
role in attracting potential mates and synchronizing spawning efforts.
22. In the tropics there are minor seasonal changes in photoperiod and water
temperature, so these factors unlikely to act as a major cues in tropics. In some
species, there are no distinct spawning season. In other species, spawning
activities vary on a seasonal basis, with factors such as variations in rainfall,
current weather conditions and tidal strength acting as the environmental cue.
Weather changes are also an essential component of environmental cues that
can trigger migrations and reproductive onsets in fishes.
Sudden changes in water discharge due to hydropeaking may have profound
effects on reproductive success.
Hour in a day was an important variable affecting the size of reproductive
aggregations.
Predation is often the reason why reproductive migrations and onsets occur
during the night and twilight hours.
Multiple cues may interact in complex ways to cause additional variation in
spawning intensity.
23. • In the Indian subcontinent, a vast majority of freshwater fishes
breed during the monsoon season when rainfall is heaviest.
• In Cyprinus carpio, start of maturation process is triggered by a
combination of increasing daylength and the commencement of the
spring - rise in water temperature. Cessation of spawning activity
due to inhibitory effects of high water temperature during summer.
• Salmonids that spawn in autumn are influenced by gradually
increasing photoperiods followed by decreasing ones or even short
photoperiods.
25. Natural food of commercially important finfish and shellfish
larvae from egg to adult
Yolk
Protein or Fat
Yolk granules smaller at the periphery towards
center, unite and forming a homogenous mass.
Eggs with amount of yolk
Microlecithal eggs- are small with little yolk. Eg:
Bivalves
Mesolecithal eggs- have relatively more yolk
than microlecithal eggs. Eg: Lampreys
Macrolecithal eggs- have a large yolk. Eg:
Cephalopods
26. Larva and juvenile in fishes
Yolk sac larva or Pro larva – which retains the yolk. The yolk sac
contains all the essential nutrients to feed the larvae and to help
it grow. Larva will feed from yolk sac until it grows bigger and
becomes able to feed by itself.
Pre-larva – which starts feeding on external food like phyto or
zooplankton, mouth will be well developed, gut will be long in
case of herbivorous and short in case of carnivorous.
Post-larva – Pre adult stage, resembles adult. Herbivorous or
carnivorous – mouth may be superior, inferior or terminal –
digestive system well developed.
27. Important live food organisms
Unicellular organisms
Yeast
Algae
Live animal prey
Copepod
Cladocerans
Rotifer
Artemia
34. Food and feeding habits of Shellfishes
Penaeid Shrimps
Penaeid shrimps are mostly omnivorous, feeding at the muddy bottom.
Their post-larvae and juveniles feed on detritus but sub-adult prawns prefer
polychaetes, bivalves, gastropods, benthic copepods, ostracods, amphipods and
foraminifers.
The adults of larger penaeids become predaceous and feed on cephalopods and
smaller species of prawns and fishes.
Non-penaeid Shrimps
Feeds on detritus
35. .
Marine Crabs
• Crabs feed mainly on smaller crustaceans, fishes, molluscs, polychaetes, detritus,
bits of plant and other organic materials.
Lobsters
• Lobsters generally prefer mussel and clam. Occasionally, they eat smaller
crustaceans, polychaetes, fishes while scavenging.
Cephalopods
• The cephalopods are generally carnivorous and their food consists of teleost fishes,
crustaceans and other cephalopods.
• Cannibalism is common among cephalopods. Feeding intensity decreases during
the spawning season
36. Reference
• Laprise, R., & Pepin, P. (1995). Factors influencing the spatio-temporal
occurrence of fish eggs and larvae in a northern, physically dynamic
coastal environment. Marine Ecology Progress Series, 122, 73-92.
• Tanaka, S. (1974). Significance of egg and larval surveys in the studies of
population dynamics of fish. In The Early Life History of Fish: The
Proceedings of an International Symposium Held at the Dunstaffnage
Marine Research Laboratory of the Scottish Marine Biological Association
at Oban, Scotland, from May 17–23, 1973 (pp. 151-157). Berlin,
Heidelberg: Springer Berlin Heidelberg.
• Khanna, S. S., & Singh, H. R. (2016). A textbook of fish biology and fisheries.
Naraendra Publishing House.
• Kunz-Ramsay, Y. (2013). Developmental biology of teleost fishes (Vol. 28).
Springer Science & Business Media.
• Scrimshaw, N. S. (1945). Embryonic development in poeciliid fishes. The
Biological Bulletin, 88(3), 233-246.