This is a presentation about the culture and breeding aspects of Red Sea bream,Pagrus major (Chrysophrys major).This fish have high aquaculture Importance today because of its meat quality and high growth rate
This document provides details on the design of components for a carp hatchery complex. It discusses calculating brood fish requirements based on production targets, sizing spawning and incubation pools, and estimating nursery pond area. Brood fish of 1300kg are needed for 50 million spawn production annually. A 5m diameter spawning pool and 2.4m diameter incubation pool are designed to support 30 lakh egg production. A 15,000 liter overhead water tank is sized to supply these units. A 2.5 hectare nursery area is required to rear 50 million fry over 5 crop cycles.
Fish stocking involves releasing fish into bodies of water to boost recreational fishing opportunities or rehabilitate degraded fish stocks. There are two main categories of stocking: put-grow-take releases small fish that grow to catchable size, while put-and-take places large fish for immediate catching. Stocking can also aim to enhance species diversity or conserve genetic diversity of endangered populations. However, problems can arise if stocking is not properly planned, such as overpopulation of target species that compete for resources, or imbalances between fish populations.
This document discusses seed production of the Asian catfish (Clarias batrachus). It describes the catfish's importance as a food fish and its distribution in India, Bangladesh, and Thailand. The document outlines the process for broodstock development, including tank setup, feeding, and selection of brood fish based on size and secondary sexual characteristics. It provides details on the hormone injection process for induced spawning and the subsequent stripping of eggs and fertilization. Larval rearing is also summarized, from initial feeding of hatchlings to growing fingerlings in outdoor tanks.
This document discusses the feeding habits and nutritional requirements of fish at different life stages. It begins by explaining that fish require energy, amino acids, fatty acids, vitamins, and minerals to sustain life and promote growth. It then discusses the feeding behaviors and nutritional needs of fish larvae, including their underdeveloped digestive systems and reliance on plankton and zooplankton. The document also categorizes different types of food sources for fish and classifies fish based on their dependence on food types and positions in the water column. Specific examples are provided of the feeding behaviors of fish larvae, juveniles, and adults.
This document discusses fish seed certification and quarantine procedures. It covers topics like quality assurance of fish seeds, certification processes in different countries, guidelines for good aquaculture practices, and general principles and considerations for quarantine facilities. Quarantine involves isolating aquatic animals to observe for diseases and involves proper treatment, testing, and containment to prevent spread of pathogens.
Brood stock management and larval rearing of mud crab scylla serrata-Gayatri ...Gayatri R. Kachh
This document provides information about the mud crab Scylla serrata, including its natural range, classification, life stages, and aquaculture practices. Key points include:
- S. serrata is an economically important crab species found in mangroves and estuaries in Africa, Australia, and Asia.
- Its life stages include juvenile, subadult, and adult crabs that inhabit different zones, as well as larvae and megalopae.
- Aquaculture of S. serrata involves maintaining broodstock for breeding and larval rearing, then culturing megalopae through to market size in ponds. Proper water quality, feeding, and health management are
1 construction, preparation of ponds, seed, feed & health management of i...B. BHASKAR
This document provides instructions for constructing fish ponds in multiple steps:
1. Site selection based on soil type to ensure proper water quality and permeability.
2. Preparation of the pond site through dewatering and removal of aquatic weeds and predatory fish.
3. Fertilization of the pond bottom with manure and chemicals to promote plankton growth as fish feed.
4. Stocking the pond with fish seed and providing regular feeding and health management until harvest.
A Minimal Water Exchange Aquaculture System, also known as a Recirculating Aquaculture System (RAS), is a modern and sustainable approach to fish farming that minimizes water usage by continuously recycling and treating the water within a closed system. In this system, water is reused and treated to maintain optimal water quality for fish while reducing the environmental impact associated with traditional aquaculture methods.
The key components of a minimal water exchange aquaculture system include:
1. Fish Tanks: These are the primary units where fish are raised. The tanks are designed to provide suitable conditions for fish growth, such as appropriate water depth, temperature, and oxygen levels.
2. Filtration System: RAS incorporates various filtration components to remove solid waste, excess nutrients, and harmful substances from the water. Mechanical filters remove large particles, while biological filters foster beneficial bacteria that convert toxic ammonia into less harmful substances.
3. Water Treatment: Water treatment technologies, such as UV sterilization or ozonation, are used to control pathogens and maintain water quality within acceptable parameters. These methods help to ensure a healthy environment for the fish.
4. Oxygenation: Adequate oxygen levels are critical for fish health. RAS employs techniques such as aerators, oxygen injectors, or oxygen cones to maintain dissolved oxygen levels throughout the system.
5. Monitoring and Control: RAS relies on advanced monitoring and control systems to continuously measure and regulate parameters such as temperature, pH, oxygen levels, and water flow. This ensures optimal conditions for fish growth and allows for timely adjustments if any deviations occur.
The benefits of a Minimal Water Exchange Aquaculture System (RAS) include:
1. Water Conservation: RAS significantly reduces water consumption by recycling and reusing water within the system. It helps conserve this valuable resource and minimizes the environmental impact associated with traditional aquaculture, which often requires large amounts of freshwater usage.
2. Improved Water Quality: The water in a RAS undergoes thorough filtration and treatment, resulting in high-quality water conditions for the fish. By removing waste and controlling water parameters, RAS helps minimize the risk of disease outbreaks and promotes optimal fish health.
3. Reduced Environmental Impact: The closed-loop nature of RAS prevents the release of excess nutrients and waste into the surrounding environment, minimizing the impact on natural ecosystems and reducing the risk of pollution.
4. Increased Production Density: RAS allows for higher stocking densities compared to traditional aquaculture systems. The controlled environment and efficient waste management of RAS enable farmers to maximize production within a smaller footprint.
5. Disease Control: The controlled and isolated environment of RAS helps minimize the risk of disease transmission
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.
This document discusses fertilizers and manures used in aquaculture. It defines fertilizers as inorganic, manufactured materials that contain nutrients like nitrogen, phosphorus and potassium, while manures are organic materials made from plant and animal waste. Both can be used to increase primary productivity in aquaculture ponds by augmenting the availability of plant nutrients. Common fertilizers discussed include urea, single super phosphate, and ammonium sulfate. Common manures include cattle dung, poultry manure, pig manure and night soil. Schedules for application of fertilizers and manures during nursery, rearing and grow-out phases are provided.
Stress from factors like overcrowding, poor water quality, and injury can weaken fish's natural defenses, making them susceptible to disease. Mucus, scales, skin, and inflammation are part of fish's immune response, but stress compromises these defenses. To prevent disease outbreaks and mortality, good management practices must maintain water quality, prevent stress from handling and overcrowding, provide proper nutrition, and implement sanitation measures. Prioritizing the reduction of stressors is key to controlling disease problems in aquaculture.
Carp hatcheries have contributed to a large increase in fish seed production in India from 6,321 million fry in 1985-86 to over 37,000 million fry currently. The document discusses the history and developments of different types of carp hatchery designs used in India and other countries, including hatching pits, hapa, glass jar hatcheries, LDPE models, and Chinese circular hatcheries. It provides details on the components, operation, advantages and disadvantages of these various hatchery designs.
distribution,biology,seed collection,nursery rearing and culture techniques o...Kavitha Cingam
This document discusses culture techniques for groupers, including important species, distribution, biology, habitat, nursery rearing, and grow-out. It describes experiments conducted to develop grouper broodstock in sea cages off Visakhapatnam, India. Broodfish were stocked and grown in cages and tanks, achieving higher survival and maturity in cages. Induced spawning trials were conducted, leading to the conclusion that sea cages are better than tanks for broodstock development and domestication of greasy groupers. This represents progress toward commercial grouper seed production and farming in India.
Freshwater aquaculture relies on fish seed from hatcheries and wild sources. Hatchery management involves maintaining broodstock and producing quality seed through induced breeding and quarantine practices. The broodstock management process includes pre-spawning procedures like selection, maintenance and spawning as well as post-spawning activities such as handling, rearing and health management. Quarantine and genetic improvement programs help select broodstock with desirable traits and disease resistance. Ensuring quality seed through certification standards improves survival and growth performance. National committees in different countries formulate policies and legislation around fish seed certification and quarantine.
Design of a Partitioned Aquaculture SystemKayla Kernich
The document summarizes a proposed redesign of a partitioned aquaculture system (PAS). The goals of the redesign are to optimize algal productivity for carbon sequestration, sustain desired water quality, and maximize biomass yield. The design proposes using a well as the water source, incorporating paddlewheels for mixing, harvesting algae every 7 days using belt filters, and monitoring water quality with automated sensors. The total estimated cost is $144,186.
Daphnia and Moina are important freshwater zooplankton used as live feed in fish and shellfish hatcheries. Daphnia can be cultured through batch or continuous systems using stable tea or algal cultures, while Moina is cultured in batches or semicontinuously using algal foods. Both reproduce rapidly under optimal conditions and can reach high densities, making them suitable for mass culture as live feed.
• Fish needs some extra feed
along
with
available
natural feeds in water for
their regular growth.
• This extra feed which are
provided to fish is called
supplementary feed of fish.
Rice bran
•Refined pulse and wheat roughage
•Mustard or sesame cake
•Fish-meal (fish powder)
•Blood and innards of bird or animal
•Green leaves of various vegetables
•Minerals and vitamins
•Kitchen leftovers, etc.
This document discusses biosecurity in aquaculture. It defines biosecurity as measures adopted to secure a disease-free environment in all phases of aquaculture. It identifies different levels of biosecurity including external and internal barriers to prevent the spread of disease. Components of biosecurity include quarantine, sanitation, and disinfection. Recommended protocols for sanitation and disinfection include being careful with live foods, proper storage and usage of manufactured feeds, and good overall system cleanliness. The document also discusses biosecurity strategies for shrimp production specifically.
This document provides taxonomic classification and information about groupers, including their life cycle, reproduction, commonly cultured species, hatchery design considerations, and broodstock acquisition and management. Groupers are popular aquaculture species in Asia-Pacific known for their fast growth and hardiness. They are mostly protogynous hermaphrodites that change sex from female to male. Hatchery design focuses on biosecurity to prevent diseases like viral nervous necrosis. Broodstock are selected based on health and size criteria and held in large tanks before spawning.
Breeding And Culture Of Seabass And SiganidsRidzaludin
This document provides information about breeding and culturing two species of marine fish: Asian seabass (Lates calcarifer) and orange-spotted rabbitfish (Siganus guttatus). It describes the taxonomy, morphology, life history traits, environmental tolerances, diseases, and farming methods for these species. The document also discusses setting up hatcheries, nurseries, and grow-out systems for culturing these and other high-value marine fish species.
Finfish breeding and hatchery management pdfKartik Mondal
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.
This document discusses the design and construction of fish farms. It notes that fish farming has occurred for centuries using simple ponds and structures. It outlines important considerations for selecting a fish farm site, such as water availability, temperature, soil type, and proximity to markets. The document then describes extensive and intensive fish farming systems and provides details on designing earthen ponds, including pond shape, buildings, water supply and drainage, and bank construction. It stresses that proper design and construction are essential for successful fish production.
Perspectives of marine fish farming in NE Brazil (in Portuguese)Alberto Nunes
O documento apresenta uma perspectiva da piscicultura marinha no Nordeste do Brasil. Discute o potencial da atividade no país, destacando que a reprodução e larvicultura de peixes marinhos não são impedimentos, mas os altos custos sim. Também resume os parâmetros de desempenho de cultivo de espécies como barramundi, beijupirá e garoupas em outros países.
The document describes various identifying features of different fish species at different life stages. It notes physical characteristics like spots, stripes, coloration and markings on bodies and fins that can be used to identify the fish as juveniles or adults. Pictures are included but require additional software to view them.
Ginseng and other medicinal plants. An old herbal book with information on the cultivation and medicinal use of herbs found in the woods. A very useful guide complete with pictures and descriptions. From Gloucester, Virginia Links and News website. Visit us for more incredible content.
1. Mosquito fish (Gambusia affinis) are small, live-bearing fish that can be introduced to control mosquito populations. They are voracious eaters of mosquito larvae.
2. Female mosquito fish give birth to live young and can have multiple broods per year, allowing populations to establish rapidly. They have a modified anal fin that allows males to deposit sperm inside females.
3. Mosquito fish are hardy and adaptable, surviving in a wide range of temperatures and water qualities. They primarily eat mosquito larvae but can negatively impact native fish populations through competition and predation.
YSI Feed Smart Aquaculture Software OverviewXylem Inc.
The Feed Smart Feed Timer is software that:
1. Can be used with YSI's 5200A and 5400 continuous water quality monitors or independently with most powered feeders.
2. Allows for automated fish feeding on a timed or continuous schedule taking into account daily feed amounts, number of feedings, and water quality parameters like dissolved oxygen, temperature, and pH.
3. Records feeding events and parameters to evaluate feeding programs and detect any water quality issues.
Grouper are a family of fish found in marine environments around the world. They have stout bodies, large mouths, and come in a variety of colors depending on species. While not fast swimmers, some grouper species can grow very large, over a meter in length and 100 kg in weight. Grouper reproduce through both sex change and dedicated sexes depending on species, with larger males typically controlling harems. They are an important part of marine ecosystems, preying on other fish and invertebrates while also serving as prey for larger predators.
Introducing the Laboratory of Aquaculture & Artemia Reference Center, Ghent U...Jean Dhont
The Laboratory of Aquaculture & Artemia Reference Center of Ghent University is a leading research and education center specialised in larval nutrition of aquatic organisms, microbial management, disease control, Artemia fundamental and applied research
Las auditorías de certificación de Buenas Prácticas de Acuicultura (BAP) permiten a las empresas acuícolas demostrar su compromiso con la seguridad alimentaria, el cuidado ambiental y el bienestar animal. La certificación BAP cubre aspectos como la calidad del agua, la salud de los animales, la seguridad de los trabajadores y la trazabilidad de los productos. La empresa chilena Cermaq recibió la máxima calificación de cuatro estrellas BAP para toda su producción de salmón, lo que resp
FRESHWATER FARMING OF BRACKISHWATER SHRIMP, PENAEUS MONODON (FABRICIUS) WIT...American Research Thoughts
Abstract: Brackish water shrimp (Penaeus monodon) farming expanded rapidly after the technical
viability of this culture system was established and farmers discovered that the high profits derived
from shrimp production could easily offset increased costs associated with this culture. These factors
facilitate the spread of brackish water shrimp farming into freshwater agricultural areas of Purba
Medinipur district of West Bengal that never experience salt water intrusion. The emergence of
brackish water shrimp farming within paddy growing regions of Purba Medinipur district has raised
concerns regarding potential environmental impacts and the suitability of conducting this activity
within highly productive freshwater agricultural areas. In the present study an attempt had been
made to farm the black tiger shrimp, Penaeus monodon in almost freshwater condition with
innovative technologies in 04 earthen tanks each with 0.4 ha water spread area under Contai -III Dev.
Block in Purba Medinipur district in the year 2011 (April to August). The PCR tested P. monodon
seeds (PL15) were stocked in all freshwater earthen tanks after proper acclimatization @
50,000nos/tank. The salinity of the tanks was recorded between 0.0063 ppt to 0.04 ppt. The shrimps
were fed with branded feed and the feeding schedule was based on check-tray method as well as a feed
chart given by the concerned manufacturer.
Barley is the fourth most important cereal crop after wheat, maize, and rice. It originated in Asia and Ethiopia and was one of the first crops domesticated along with wheat and peas. Barley is grown for both animal feed and human consumption products. It is well adapted to temperate regions and can tolerate drought and salinity better than other cereals. In Pakistan, barley is grown on around 80,000 hectares annually, producing around 78,000 metric tons, with most production occurring in the provinces of Deir, Bahawalnager, and Bajour agency.
This experiment tested the growth rates of barley plants in either potting soil or pine soil, with and without the plant nutrient Miracle-Gro. The researchers planted single barley seeds in four pots, two with pine soil and two with potting soil, one of each including Miracle-Gro. They measured the growth of the barley plants weekly over eight weeks, finding that the barley grew fastest in potting soil with Miracle-Gro, reaching over 47 centimeters tall.
1. Rotifers are commonly used live feed for marine fish larvae. They are small, tolerate a wide range of conditions, and reproduce rapidly.
2. Mass culture of rotifers involves three units - one for culturing algae food, one for stock culture, and one for large-scale production. Proper temperature, pH, salinity, and aeration are needed.
3. Rotifers are enriched by feeding them algae rich in omega-3 fatty acids to increase their nutritional value for fish larvae. Enriched rotifers are stored at low temperatures to preserve fatty acid levels.
YSI Advancements in Monitoring & Control Technology Webinar 1213Xylem Inc.
Webinar covering product advancements that improve system performance, productivity and efficiency with M&C water quality technology.
Topics include:
• optical based dissolved oxygen
• connectivity/networking options
• automated feeding with YSI Feed Smart
• data management with AquaManager and the AquaViewer App
• alarming options
Applications for M&C systems include tank-based/RAS commercial aquaculture, aquaculture research, live haul, public aquariums, algae culture and anyone interested in aquaculture monitoring and control technology to improve performance, productivity and efficiency.
This document provides information about culturing live feeds for hatcheries, focusing on microalgae culture. It discusses the importance of live feeds like microalgae and zooplankton for larval fish. Common microalgae used include Chaetoceros, Isochrysis, Pavlova, and Tetraselmis. Methods for mass culturing microalgae include batch, semi-continuous, and continuous systems. Batch culture is most common and involves growing algae in increasing volumes harvested at peak density. Facilities use bags or tanks with artificial lighting and aeration to produce microalgae as live feed.
This document discusses Penaeus monodon, also known as giant tiger prawn. It covers the scientific classification of P. monodon and provides an overview of grow-out techniques including extensive, semi-intensive and intensive culture methods. The production cycle and physiology of prawns is described. Other topics covered include geographical location considerations, pond preparation, soil and water management, prawn feed requirements, harvest, and disease control measures.
This document provides information on the African catfish (Clarias gariepinus). It discusses the biology of C. gariepinus and the closely related species C. anguillaris. It also describes the natural breeding and artificial propagation of C. gariepinus, including hormone treatment of broodfish, incubation and hatching of eggs, nursing of fry, and feeding regimes for early fry and advanced fry in hatcheries. Semi-intensive polyculture of catfish and tilapia in earthen ponds is also summarized.
Transport of hatchlings, fry, and fingerlings is common in aquaculture. Proper techniques involve understanding fish physiology and mortality causes during transport. Seed can be collected from wild or hatcheries. Major carps are collected from flooded rivers during monsoon season. Seed from estuaries and coastal waters include milkfish, mullets, pearlspot, and seabass. Bundhs are seasonal flooded areas that stimulate breeding. Induced spawning techniques breed species that don't spawn in captivity using hormones. Transport uses open or closed oxygenated systems. Factors causing mortality are oxygen depletion, waste accumulation, temperature fluctuations, and stress. Anaesthetics and antibiotics are used to reduce stress and prevent disease.
Culture Of Cobia- Its Biology, Seed Collection & Culture TechniquesHaladharHembram2
Cobia , Rachycentron canadum also known as Lemon fish or Ling is an oceanodromous , migratory and pelagic fish that lives in brackish and marine waters.
The fish is popular known by the common names-Black kingfish, Black salmon, runner or sergeant fish, crab eater and Sea murrel.
It is a highly priced game fish with high market value both in domestic and international markets.
Cobia known for its excellent meat quality is a famous premium food fish highly preferred by people in Taiwan and Japan. The white meat of the fish is served in restaurants as raw fish called Sashimi.
The fast growth rate, adaptability to captive breeding (attains 6-8 kg/year) are the major attributes which makes cobia as an excellent candidate species for aquaculture.
Cobia is one of the marine finfish species with high aquaculture potential particularly for cage culture in India.
Groupers belongs to the family Serranidae.
⚫ Groupers are classified in 14 genera of the subfamily Epinephelinae, which comprises at least half the approximately 449 species in the family Serranidae.
⚫ Several grouper species have been raised on a commercial scale, but mostly by growing out captured wild juveniles.
Fish farming involves raising fish commercially, usually for food. The most common fish species raised on farms are salmon, carp, tilapia, seabass, catfish, and cod. There is increasing demand for fish which has resulted in overfishing, so fish farming offers another source. Fish farms can be extensive or intensive. Extensive farms rely on natural food sources while intensive farms require artificial feeding and water treatment. Common fish farm systems include cages, ponds, composites of different fish species, and integrated systems that reuse water. Issues with fish farms include the use of wild fish in feeds and the high densities that can cause disease.
CAGE CULTURE OF FISH THEIR TREND,STATUS AND PRODUCTION Ashish sahu
Cage culture is an aquaculture production system where fish are held in Cage. Cage culture of fish utilizes existing water resources but encloses the fish in a cage which allows water to pass freely through the enclosures and the surrounding water body. Cages are used to culture several types of shell fish and finfish species in fresh, brackish and marine waters. Cages in freshwaters are used for food fish culture and for fry to fingerling rearing.
In 1950s modern cage culture began with the initiation of production of synthetic materials for cage construction. Fish production in cages became highly popular among the small or limited resource farmers who are looking for alternatives to traditional agricultural crops. The mesh size of the cage is kept smaller than the fish body. In India cage culture have been attempted first for Air breathing fish. Cage mesh netting made from synthetic material that can resist decomposition in water for a long period of time. Cage are used to culture several type of shell fish and fin fishes in fresh , brackish and marine water. Cage in fresh water are used for food fish culture and for fry to fingerling rearing. Cages are generally small, ranging in freshwater reservoirs from 1 square meter (m2) to 500 m2.
Definition –
Cage culture is a system in which the cultured Fish 0r animal are enclosed from all side allowing water to pass freely through the enclosures and the surrounding water body.
HISTORY-
Cage culture seem to have developed around 200 year ago in Cambodia where fisherman used to keep clarias spp. And some other fishes in bamboo made cage. Cage culture is traditional in part of Indonesia also attempted for the first time in air breathing fishes in swamp for raising major carp in running water in the river, Yamuna and Ganga at Allahabad and for raising Common carp , Catla , Silver carp, Rohu , Snakehead and Tilapia in still water body of Karnataka. In India sea cage start in 2007 for culture sea bass at Vishakhapatnam by CMFRI. anchored in streams which are practically open sewers. Common carp , where cage are in the southern USA. Around 80 species are being culture in cage. In India cage culture was initially culture in bamboo cage is practice in west java, since early 1940. Modern cage culture in open water bodies probably originated in Japan in early 1950. According to FAO cage culture is being practiced in more than 62 countries and has a become high tech business in developed countries such as floating and submerged cage culture of Salmonids in Norway, Canada and Scotland, Tuna and Yellowtails in Japan , Chinese carp in China, and catfish.
Seed production and breeding of pearl Oyster &.pptxAbhayBamaniya2
so this presentation includes breeding and seed production of both edible and pearl oyster, which are basically same in a way. note that this does not includes pearl formation in the pearl oyster but after reading this presentation you might learn how to the culture the oyster. good luck! and have fun.
This document provides guidance on setting up a saltwater aquarium, including:
1) Easy to keep fish for beginners include damselfish, gobies, cardinalfish, and clownfish. Suitable corals are leather corals, mushroom anemones, colonial anemones, and cleaner shrimp.
2) The aquarium should be at least 100 liters to maintain water quality. Combining fluorescent and metal halide lighting provides optimal conditions for corals and invertebrates.
3) Coarse coral sand makes an ideal substrate, providing bacteria habitat and stabilizing pH.
Hill areas offer good scope for the development- of fisheries—both for commercial and sport purposes.
The coldwater fishery resources in India comprise high and mid-altitude lakes, rivers, streams, their tributaries and reservoirs dammed across such rivers.
The importance of coldwater fisheries lies in their unique biodiversity, valuable germplasm and maintenance of environmental quality in hills.
Coldwater fishes breed naturally but since some species have been listed as endangered, therefore artificial breeding is now being practiced to restore the diversity.
The document provides information on the culture of mud crabs. It discusses the scientific classification of mud crabs, their biology, hatchery technology, and culture methods. Mud crabs can be cultured through monoculture or polyculture. They reach market size within 6 months when cultured and common diseases include white spot disease and bacterial shell diseases. The document concludes that mud crab farming is becoming popular due to demand and provides alternative livelihood opportunities through crab fattening.
Fingerlings must be handled carefully from hatchery to stocking to minimize stress and disease. Proper procedures include ordering fish in advance, quarantining and treating them with saltwater upon arrival at the hatchery. When transporting, the water quality of transport containers and receiving ponds/tanks should be similar to reduce stress. Fingerlings should be acclimated gradually to receiving waters. Upon stocking, fish should be carefully counted and released when environmental conditions are suitable to avoid shock. Adhering to best practices helps ensure healthy fingerlings that survive to market size.
Fingerlings must be handled carefully from hatchery to stocking to minimize stress and disease. Proper procedures include ordering fish in advance, quarantining and treating them with saltwater upon arrival at the hatchery. When transporting, the water quality of transport containers and receiving ponds/tanks should be similar to reduce stress. Fingerlings should be acclimated gradually to receiving waters. Upon stocking, fish should be anesthetized, counted and monitored to ensure health and survival. Communication between hatcheries and farmers is important for rearing quality fingerlings.
distribution,biology,seed collection,nursery rearing and culture techniques o...Salmashaik26
This document discusses culture techniques for grouper species, including distribution, biology, nursery rearing, and grow-out. It summarizes techniques for broodstock development using wild-caught groupers in sea cages, induced spawning trials, and successful maturation of groupers within one year when reared in open sea cages compared to indoor tanks. The document concludes that continuous supply of grouper seeds is needed to develop grouper aquaculture in India and that broodstock development in sea cages is an important step towards captive seed production.
The document provides information about the mud crab (Scylla serrata), including its classification, distribution, ecology, and methods for farming and hatchery management. It notes that mud crabs are found naturally in the Indo-Pacific region and are an economically important species. Mud crab farming can be done using grow-out systems, where young crabs are raised for 5-6 months until market size, or fattening systems, where soft-shelled crabs are raised for a shorter period. Hatchery management involves broodstock selection and care, spawning and larval rearing techniques, and achieving survival rates as high as 18.1% compared to the world average of 3-3.5
Biology and Aquaculture Pearl spot E. suratensisB. BHASKAR
This document provides information on the biology, aquaculture, and culture of Pearl spot fish. Some key points:
- Pearl spot is an indigenous fish found along India's coasts that is important for aquaculture. It is cultured in brackishwater and freshwater environments.
- Details are provided on its classification, life cycle, breeding/spawning behavior, hatchery seed production techniques, and pond preparation for culturing.
- For grow-out culture, Pearl spot can attain market size within 8-10 months under monoculture or polyculture. Yields of 1,000 kg/ha/year are possible at stocking densities of 20,000-30,000 fish/ha. Pro
This document discusses polyculture of carp fish in Bangladesh. It describes that polyculture involves culturing multiple fish species together that have different feeding habits and ecological niches. Common carp species cultured together in Bangladesh include various types of indigenous carp like rohu, mrigal carp, and exotic carp like silver carp. Effective polyculture management requires selecting compatible species, maintaining suitable water quality parameters, providing adequate natural and supplemental food, monitoring fish health and growth, and preventing diseases. Polyculture aims to maximize fish production from a water body by fully utilizing available resources.
This document discusses traditional and modern aquaculture systems. It describes different aquaculture systems including extensive, semi-intensive and intensive systems. Cage culture and raceway pond systems are introduced as open systems that make use of existing water bodies. Close recirculating aquaculture systems are also summarized as they allow for intensive aquaculture production with environmental control. The document outlines advantages and disadvantages of different aquaculture methods.
Aquaculture is the most reliable sector to the providing world nutrias food. It is all depended on the cultivable species. Asian seabass is one of the candidate species for aquaculture because of the wide range of water quality tolerance, growth performance, and consumer preference. The Indian and Western Pacific Oceans are where Asian seabass is found in its natural habitat. It can be cultured in the earthen pond, floating or stationer cages, and recirculating system. Seed resources are available in rivers and lakes of fresh water, but aquaculture is the depending on the hatchery that produces seed because of the superior growth production. In the nursery phase, cannibalism is predominant in Asian seabass cultivation, which will improve via the grading of a shooter. Feeding is one of the important management for good growth performance and reducing cannibalism to give the optimum feed requirements. The growth rate of the Asian seabass is 400-600 g in 4 to 6 months. Asian seabass farmers are suffering from some infectious and non-infection diseases, it will improve via the good management practices of the culture promises. In this review paper, some key points of Asian seabass farming are covered for better understanding.
Application of biotechnology_in_lipid_processing_and_valueVishnuraj R S
Lipid biotechnology uses enzymes like lipases to modify lipids and produce specialty products. Lipases can hydrolyze or interesterify triglycerides and are used in food processing. Glycerol, a byproduct of biodiesel production, can be converted to high-value chemicals like dihydroxyacetone and 1,3-propanediol using biocatalysts. Supercritical fluids like carbon dioxide are also used to efficiently extract lipids due to their gas-like diffusion properties.
This document discusses lipids in fish nutrition. It defines lipids and their subclasses, and notes that they are the principal form of energy storage in animals. The document categorizes lipids and describes their composition, functions, and essential fatty acid requirements in fish. It also discusses negative aspects like the lability of polyunsaturated fatty acids to oxidation. In conclusion, lipids are an important source of energy and building blocks, but high levels can suppress growth and negatively impact product quality.
This document discusses silverbelly fish fisheries in India. It notes that silverbellies are small fish found in shallow waters along the Indian coast that are an important resource, with annual landings of around 5,000 tons. The majority of landings come from trawling in the southern states of Tamil Nadu and Kerala. Silverbellies have a unique distribution along the Indian coast and consist of 21 species, though diversity is highest in the Palk Bay and Gulf of Mannar regions of southern Tamil Nadu. They spawn year-round but with one or two longer peak seasons. Due to their importance as a fishery resource, management of silverbelly stocks is important.
This document provides information on sea cucumbers (holothurians), including their biology, life cycle, reproduction, and aquaculture. It discusses that holothurians are economically important as food and that their skin and muscle layers are edible. It also describes their internal anatomy, feeding behavior, spawning season from March to April when eggs and sperm are released, and larval development. The document outlines aquaculture techniques for sea cucumbers such as pond culture and discusses broodstock maintenance and artificial breeding.
Anchovies are a small, silvery fish found throughout the world's oceans in temperate waters. There are over 140 species of anchovy across 17 genera. Major anchovy fisheries exist in India, Indonesia, Malaysia, Sri Lanka, and along the coasts of Peru, Japan, and South Africa. Anchovies are an important commercial resource, supporting fisheries through use of nets, purse seines and other gear. They are a nutritious food high in protein, vitamins, and minerals that provide numerous health benefits such as supporting heart health, skin health, tissue repair, weight loss and eye health.
Clupeids, including sardines, anchovies, and shads, make up a significant portion of marine fish landings in India, accounting for around 38% annually. Whitebaits are an important component of anchovy landings, contributing an average of 55,415 tonnes per year. Golden anchovy landings have declined in recent years. Hilsa shad landings increased substantially from 1999-2008, with the species contributing over 80% of total shad landings on average. Management strategies must account for the multi-species nature of clupeid fisheries.
Feed formulation is the major part of aquaculture.The main objective of feed formulation is to utilize the knowledge of nutrient requirements, locally available feed ingredients and digestive capacity of fish for the development of a nutritionally balanced mixture of feed stuff…
This document discusses infectious pancreatic necrosis (IPN), a viral disease that affects young salmonids. It is caused by the IPN virus, a birnavirus with two RNA segments. The disease causes high mortality in fry and fingerlings. While it was first described in Canada in 1941, it has since spread worldwide and can be transmitted through infected water, equipment, fish, eggs and carriers like birds. Clinical signs include swimming abnormalities, loss of appetite and paleness. Diagnosis involves detecting viral lesions on the pancreas and intestines. Management requires controlling water quality, screening broodstock, disinfecting eggs and vaccinating fish. Many fish species can be infected and act as asymptomatic carriers.
This document discusses the application of biotechnology in lipid processing and value-added products from fats and lipids. It describes how various biocatalysts like lipases can be used to modify lipids and transform oils and fats through processes like interesterification. It also discusses how glycerol, a byproduct of biodiesel production, can be converted to valuable intermediates. Supercritical fluid technology using carbon dioxide is also highlighted as an environmentally friendly method for lipid extraction.
The Vembanad Lake estuarine system in Kerala, India is an important fishery resource but its health is declining. It supports over 100 fish and shellfish species and once produced over 8,500 tons of catch annually, but production has fallen significantly. Key threats include obstruction of water flows, sand mining, habitat destruction, pollution, and unsustainable fishing practices. Conservation efforts are needed to restore the lake's fisheries and protect the livelihoods of local fishing communities.
Traditional aquaculture practices have been used in India for centuries, as documented in ancient texts. These include brackish water shrimp and fish farming using tidal flows. In western India, Bhery culture involves constructing ponds surrounded by earthen dykes, with sluice gates to control tidal water entry and drainage. Sea water and naturally occurring plankton and organic matter support fish growth. In southern India, Pokkali fields use similar tidal flooding of rice paddies for shrimp culture after the rice is harvested. These traditional low-input methods continue today in some areas, though productivity is low.
The document discusses methods for collecting and preserving various types of crustaceans. It describes different nets, traps, and techniques used to collect crabs, lobsters, prawns, and cladocerans. The key preservation methods include fixation in formalin, storage in 70-75% ethyl alcohol, and adding glycerol or propylene glycol to prevent desiccation. Regulations for crab traps and nets are also outlined.
The document discusses several major environmental problems facing the world including climate change, ozone depletion, biodiversity loss, ocean exhaustion, desertification, pollution, deforestation, and population growth. It provides details on the causes and impacts of issues like global warming, the Antarctic ozone hole, desertification, pollution of oceans, air, water and soil. Solutions proposed include sustainable development, green economy, education programs, effective policy implementation, and individual action along with government and non-government groups working together. The presentation calls for immediate intervention to address the alarming global environmental crisis.
The document discusses air pollution, its causes, effects, and methods of control. It states that air pollution primarily comes from burning fossil fuels by industries and vehicles, which release pollutants like sulfur oxides, nitrogen oxides, and particulate matter. Some pollution also occurs naturally from volcanoes, forest fires, and animal respiration. The health effects of air pollution include respiratory diseases. Control methods discussed include particulate filters and scrubbers, changing combustion processes, catalytic converters on vehicles, and biofilters to break down pollutants.
Mail Server Configuration Using App passwords in Odoo 17Celine George
In Odoo 17, we can securely configure an email server to send and receive emails within the application. This is useful for features like sending quotations, invoices, and notifications via email. If our email service provider (e.g., Gmail, Outlook) supports app passwords, we can use them to authenticate our Odoo instance with the email server.
This is an introduction to Google Productivity Tools for office and personal use in a Your Skill Boost Masterclass by the Excellence Foundation for South Sudan on Saturday 13 and Sunday 14 July 2024. The PDF talks about various Google services like Google search, Google maps, Android OS, YouTube, and desktop applications.
APM event held on 9 July in Bristol.
Speaker: Roy Millard
The SWWE Regional Network were very pleased to welcome back to Bristol Roy Millard, of APM’s Assurance Interest Group on 9 July 2024, to talk about project reviews and hopefully answer all your questions.
Roy outlined his extensive career and his experience in setting up the APM’s Assurance Specific Interest Group, as they were known then.
Using Mentimeter, he asked a number of questions of the audience about their experience of project reviews and what they wanted to know.
Roy discussed what a project review was and examined a number of definitions, including APM’s Bok: “Project reviews take place throughout the project life cycle to check the likely or actual achievement of the objectives specified in the project management plan”
Why do we do project reviews? Different stakeholders will have different views about this, but usually it is about providing confidence that the project will deliver the expected outputs and benefits, that it is under control.
There are many types of project reviews, including peer reviews, internal audit, National Audit Office, IPA, etc.
Roy discussed the principles behind the Three Lines of Defence Model:, First line looks at management controls, policies, procedures, Second line at compliance, such as Gate reviews, QA, to check that controls are being followed, and third Line is independent external reviews for the organisations Board, such as Internal Audit or NAO audit.
Factors which affect project reviews include the scope, level of independence, customer of the review, team composition and time.
Project Audits are a special type of project review. They are generally more independent, formal with clear processes and audit trails, with a greater emphasis on compliance. Project reviews are generally more flexible and informal, but should be evidence based and have some level of independence.
Roy looked at 2 examples of where reviews went wrong, London Underground Sub-Surface Upgrade signalling contract, and London’s Garden Bridge. The former had poor 3 lines of defence, no internal audit and weak procurement skills, the latter was a Boris Johnson vanity project with no proper governance due to Johnson’s pressure and interference.
Roy discussed the principles of assurance reviews from APM’s Guide to Integrated Assurance (Free to Members), which include: independence, accountability, risk based, and impact, etc
Human factors are important in project reviews. The skills and knowledge of the review team, building trust with the project team to avoid defensiveness, body language, and team dynamics, which can only be assessed face to face, active listening, flexibility and objectively.
Click here for further content: https://www.apm.org.uk/news/a-beginner-s-guide-to-project-reviews-everything-you-wanted-to-know-but-were-too-afraid-to-ask/
2. Red seabream, Pagrus major (Temminck and Schlegel, 1843) is a
demersal species that occurs in the northwest Pacific (the northeastern
part of the South China Sea northward towards Japan) at depths between
10 and 50 m.
The red sea bream, Pagrus major (Chrysophrys major), is the most
valuable marine fish in Japan.
A first trial to culture it has been made at a hatchery located at Seto
Inland Sea coast in 1902 (KAJIYAMA, 1937). The hatchery was soon
closed because of difficulty in rearing the larvae.
SHlKAMA, YMASHITA and NISHIZUKA succeeded in rearing 22 red
sea bream fry from the eggs for the first time in Japan in 1962
(YAMASHITA, 1967).
These successes were achieved on an experimental scale, and therefore,
further experimentation was necessary before developing mass
production methods.
3. 1967, NOGUCHI observed natural spawning' of cultured red sea breams in
a large tank at Naruto Aquarium, Tokushima, Japan+ (NOGUCHI, 1968).
Based on these successes, research has been carried out in order to find a
mass rearing method for red sea bream larvae at the hatcheries belonging to
Seto Inland Sea Fish Farming Association (ANONYMOUS, 1974).Most
sparid species have been used in mariculture and cultivated in cages.
CLASSIFICATION AND CHARACTERS
Kingdom: Animalia (animals)
Phylum: Chordata (chordates)
Subphylum: Vertebrata (vertebrates)
Superclass: Gnathostomata (jawed vertebrates)
Class: Actinopterygii (ray-finned fishes)
Order: Perciformes
Family: Sparidae
Genus: Pagrus
Species: Pagrus major
4. The family Sparidae contains 35 genera and112 species, distributed
mainly in tropical and temperate waters of the Atlantic, Pacific and
Indian oceans (Froese and Pauly, 2005).
Eighteen of these species inhabit the Adriatic continental shelf (Jardas,
1996). Two of these belong to the genus Pagrus (Cuvier, 1816): Pagrus
pagrus (Linnaeus, 1758) and Pagrus coeruleostictus (Valenciennes,
1830).
5. DISCRIPTION
Body robust, oblong, moderately compressed. Upper profile of head convex
with a bulge above eye.
Lower jaw slightly shorter then upper. Head and upper body dark violet,
sides and belly silvery. Several small bright blue spots on upper sides.
All spines of dorsal fin tough and not elongated.
Caudal fin forked with pointed lobes. Scales moderately large, absent from
bases of soft dorsal and anal fins. Posterior margin of caudal fin black, lower
margin white.
Dorsal spines (total): 12; Dorsal soft rays (total): 10; Anal spines:
3; Anal soft rays: 8.
Body with many bluish dots when fresh. Shallow body, body depth 2 or
more in SL.
Transverse scales 6.5-7.5. All spines of dorsal fin are tough and not
elongated. Posterior margin of caudal fin black, lower margin is white.
Occurs from 10 to 50 m depths, often on rough grounds, but also on softer
bottoms.
6. NATURAL DISTRIBUTION
They are mainly distributed in Northwest Pacific: northeastern part of South
China Sea (Philippines excluded) northward to Japan.
HATCHERY DESIGN
The basic considerations in establishing a fish hatchery are: (i) which
site is suitable, (ii) what is the area of the site and the facilities required
in relation to the goals or objectives of the hatchery, and (iii) how will
the hatchery be managed.
7. It is of primary importance to conduct a feasibility study to determine the suitability
of the site.
This should be done prior to the establishment of the hatchery. There are three
factors which must be considered in designing a fish hatchery:
(i) species,
(ii) production target, and
(iii) level of financial input.
In addition, the facility requirements will depend on the nature of organization to
run the hatchery.
For government pilot projects, some laboratory support facilities are required.
Criteria in the selection of sites for seabream hatchery
1. Seawater supply
The seawater used in a hatchery should be clean, clear and relatively free
from silt. The water quality should be good with minimal fluctuation in
salinity all year round. Suitable sites are usually found near sandy or rocky
shore. Sites which are not suitable for hatchery include areas which are
heavily influenced by rain or turbulence.
An added advantage of having a site on rocky shores is that good quality
seawater is relatively near the shoreline. This reduces the cost of piping
installation and pumping. The hatchery site should also be free from any
inland water discharges containing agricultural or industrial wastes.
8. 2. Accessibility
Ideally, a hatchery site should be selected in areas where there are active fish
farming operations so that the fish larvae produced can be easily transported
and distributed to the grow-out ponds and cages. The site chosen for a
hatchery must have easy access to communication and transportation
channels.
3. Availability of power source
A fish hatchery cannot be operated without electricity. Electricity is essential
to provide the necessary power to run the equipment and other life support
systems of the hatchery.
4. Topography
The ideal site should be spacious, situated on flat to gently sloping grounds,
well drained and not susceptible to floods, strong wave and tidal actions.
5. Acquisition
It is advisable to pay attention to land values early in the site selection
phase to ensure that the site is available for purchase or lease and at a price
consistent with the project budget.
9. Hatchery size
Hatchery design is aimed at achieving certain production targets which in
turn determine the size of the hatchery.
The capacity is based on an approximate ratio between tank for production
of natural food (algae and rotifer) and larval rearing tank.
The spawning tank depends on the larval requirement which is based on the
number of spawners.
SEAWATER SYSTEM
Seawater can be drawn directly from the sea or from the sump pit.
If the source of water is relatively clear, the water can be pumped directly
into the overhead filter tank and stored in the reservoir or storage tank.
if the water is turbid and contains a high concentration of suspended solids,
it must be pumped first into a sedimentation tank where the suspended
solids are allowed to settle down
Holding tanks
The holding tanks in the seabream hatchery are used for various purposes
such as for brood stock conditioning and subsequent spawning, incubation,
larval rearing and production of natural food.
13. SPAWNING AND HATCHING
Maturation
The red sea breams used for spawning are kept in net cages or concrete
tanks
(Dimensions: 10-20 m x 10 m x 5 m), for about a year or two depending
on their initial ages.
The red sea bream becomes sexually mature when 3 years old.
The spawning season extends from April to June, with a peak in early
May.
Brood stock development
There are two sources of seabream brood stock: wild-caught adults and
from ponds/cages (2–6 years old fishes averaging in weight from 3 to 5
kg).
It is advantageous to use pond or cage-reared brood stock as they are
already used to culture conditions being easier to condition and develop
them into brood fish.
14. 1. Wild brood stock collection
The fishery worker must constantly strive to minimize stress in handling
captive brood stock.
Efforts to capture seabream should be confined to areas where they are
known to occur.
The selection of a suitable gear or method of capture must also be
considered.
2. Conditioning of wild brood stock
Captured fish are placed immediately in transport tanks and taken directly to
the hatchery or holding cages.
Anesthetic is not necessary if the fish are shipped in live tanks or in aerated
transport containers.
Upon arrival at the hatchery, the fish are treated with antibiotic such as
oxytetracycline.
2 ppm for the dripping method for 24 hours and 20 mg per 1 kilogram of
fish for the injection method.
In nature, seabream is a carnivorous and feeds voraciously on live fish.
However, in captivity, they can be conditioned to feed on dead fish.
15. The uneaten feed should be removed to prevent water pollution.
3. Brood stock maintenance
The fish, whether cultivated or wild-caught, can be maintained as brood
stock in cages and concrete tanks.
(a) Cages
Floating cages are usually used for brood stock development.
The size of the cages varies from 10 to 100 sq.m in surface area with a depth
of 2 meters (dimension: 5 × 5 × 2m or 10 × 10 × 2m).
Smaller cages are more suitable because they are easier to maintain and
manage (such as in changing of net and harvesting).
The mesh size of a brood stock cage varies from 4–8 cm. Stocking density
of fish is 1 per cubic meter of water.
(b) Concrete tanks
The size of concrete tanks used for holding brood stock depends on the size
of the hatchery. It is advisable to use a bigger tank to allow the fish ample
space for swimming.
Generally, tank volume ranges from 100–200 tons (5 × 10 × 2m and 10 × 10
× 2m). Stocking rate in brood stock tank is 1 fish for every 2 cubic meters of
water.
16. Spawning and fertilization
1. Selection of spawners
The selection of spawners from the brood stock should be done months
before the beginning of natural spawning to allow ample time for the fish to
be conditioned to environmental and diet controls. Spawners are normally
selected based on the following criteria:
fish should be active
fins and scales should be complete
free from disease and parasite
free from injury or wounds
males and females of similar size groups are preferred
spawner should be at least 4–5 kg in body weight and should not be less
than 3 years old
Selected spawners are then transferred to the pre-spawning tank. The ratio of
male and female stocked in the pre-spawning tank is 1:1.
17. 2 .Care of spawners in pre-spawning tank
Immediately after stocking in the pre-spawning tank, the feeding is reduced
from 5% to 1% of the total body weight and fed once a day.
This is to prevent the fish from getting fat which can result in poor gonadal
development.
The feed given should be fresh marine fishes such as sardine, yellow stripe
thread fin, etc.
Water in the spawning tank should be maintained in good condition. This
can be achieved by changing the water about 50–60% daily.
Spawning of seabream
Presently, there are two major techniques employed in mass production of
seabream fry in Southeast Asian countries: artificial fertilization and induced
spawning.
1 .Artificial fertilization.
Spawners are caught in natural spawning grounds near the mouth of the
river or in salt water lakes, where the water depth is about 10–20m.
18. The degree of maturity of the collected spawners should be immediately
checked.
If the female has ripe eggs and the male is in the running stage, stripping is
done in the boat. The fertilized eggs can then be transported to the hatchery
for subsequent hatching.
In cases where only the male is caught, the milt is collected by stripping into
a dry glass container.
Milt is then stored in an ice box or refrigerator. The milt can maintain its
viability after a week in cold storage (5–15°C).
The preserved milt should be made available for immediate use when a ripe
female is caught. The dry method of fertilization is normally used in this
case.
The eggs are stripped directly from the female to a dry and clean container
where the milt is added.
A feather is used in mixing the milt and eggs for about 5 minutes. Filtered
seawater is then added into the mixture while stirring it and then allowed to
stand undisturbed for 5 minutes.
19. 2. Induced spawning
Two methods are normally used for inducing seabream to spawn in
captivity, e.g. hormonal injection and environmental manipulation. Both
methods would induce the fish to spawn naturally in the tank. This results in
a monthly spawning until the gonads are spent.
2.1, Induced spawning by hormone injection
After stocking seabream brood stock in the pre-spawning tank for two
months, the fish are inspected twice a month during spring tide, ovarian
maturity of the female is measured as follows: the eggs are sampled from
the female through the use of a polyethylene cannula of 1.2 mm in diameter.
The fish is either anaesthetized or inverted gently with a black hood over the
head. The cannula is inserted into the oviduct for a distance of 6–7- cm from
the cloaca.
Eggs are sucked orally into the tube by the operator as the cannula is
withdrawn. The eggs are then removed from the cannula and egg diameter
measurement is made.
20. When the seabream eggs reach the tertiary yolk globule stage or have a
diameter of 0.4–0.5 mm, the female is ready for hormone injection. In
males, only those with running milt are chosen.
The hormones usually used to induce spawning in seabream that produce
reliable results are:
Puberogen
HCG + pituitary gland of Chinese carp
Puberogen consists of 63% follicle stimulating hormone (FSH) and 34%
Leutinizing hormone (LH). The dosage usually applied is 50–200 IU/kg of
fish.
The fish will spawn at about 36 hours after injection. If no spawning occurs,
the second injection is applied 48 hours after the first injection.
The dosages of second injection should be double from that of the first
injection and can also be given 24 hours after the initial injection.
The male is usually injected at the same time as the female with a dosage of
20–50 IU/kg of fish. The fish will normally spawn within 12–15 hours after
the second injection.
21. Homogenized pituitary glands of Chinese carp are used at 2–3 mg/kg of fish
mixed with Human Chorionic Gonadotropin (HCG) at 250–1,000 IU/kg of
fish.
The time interval of application and spawning are the same when using
puberogen .
2.2 Induced spawning by environmental manipulation
Based on field observations and analysis of natural phenomena that occur
during spawning period of seabream, techniques were developed to
stimulate the fish to spawn in captivity. The following steps are necessary:
changing the water salinity to simulate fish migration
decreasing the water temperature to simulate the decreased water
temperature after rain
lowering and subsequent addition of fresh seawater to the tank in order to
simulate the rising tide, and
Follow the moon phase.
22. Initially, the salinity of water in pre-spawning tank is prepared at 20–25 ppt
before stocking the selected spawners.
After stocking, 50–60% of water is changed daily until 30–32 ppt is
reached. This will take about 2 weeks.
This will simulate the migration of fish from its growing grounds to the
spawning grounds.
At the beginning of the new moon or full moon, the water temperature in the
spawning tank is manipulated by reducing the water level in the tank to 30
cm deep at noon time and exposing to the sun for 2–3 hours.
This procedure increases water temperature in the spawning tank to 31–
32°C.
Filtered seawater is then rapidly added to the tank to simulate the rising
tide. In effect, the water temperature is drastically decreased to 27–28°C.
The fish spawn immediately the night after manipulation (1800–2000 hours)
or if no spawning occurs, manipulation is repeated for 2–3 more days.
23. Egg collection and incubation
Fertilized eggs of seabream range in size from 0.8–1 mm. They float in
the water column (pelagic) and are very transparent.
Eggs in spawning tank can be collected and transferred to incubation tanks
by either of the following procedures:
The spawning tanks are supplied with continuous flow of seawater. The
overflowing water carry the eggs into a small tank (2 × 0.4 × 0.3 m)
containing a plankton net (200μ mesh).
Eggs are collected and transferred to larval rearing tanks the following
morning.
The eggs are collected from the spawning tanks using a fine mesh (200μ)
seine net the morning after spawning.
Fertilized eggs are then transferred to incubation tank at the density of
100 eggs/liter.
The eggs will hatch at about 17–18 hours at 26–28°C after spawning.
Dead eggs which settled at the bottom are removed by siphoning.
24. Hatching rate of seabream eggs by environmental and hormonal
manipulation ranges between 40–85% and 0.1–85%, respectively.
Larval rearing
The rearing tanks are commonly fabricated from plastic, fiberglass, wood
or concrete. A typical larval rearing tank is rectangular in shape and
located outdoor. Its volume ranges from 8–10 tons (7 × 1.2 × 1m or 10 ×
1.5 × 1m).
The tanks are usually protected from strong sunshine and heavy rains by
a roof tile cover
The usual stocking density for newly-hatched larvae in rearing tank is
between 50–100 larvae/liter.
27. REARING THE LARVAE
Prelarval stage
The newly hatched larvae are introduced into floating tanks (dimensions:
about2-4 m x 2-4 m x 1.5-2 m) made of synthetic fiber cloths.
The floating tanks are hanged in a large concrete tank (water volume: 50-
200 m3).
The survival rates of pre larvae are improved in tanks with abundant
propagation of uni-cellular green algae.
In order to promote the propagation of uni-cellular green algae, small
amounts of inorganic and organic nutrients are added into the floating tank.
The optimum density of uni-cellular green algae is about 300,000 cells/ml.
Slight aeration is provided by about 8 vinyl hoses (diameter: 5 mm) per
floating tank.
28. The pre larvae are released into large concrete tanks after they have been
reared for about 10 days in the floating tanks.
The daily rate of water renewal is set to 1/4 of the total volume several days
before transferring the larvae to another rearing net cage.
Waste accumulated on the bottom is removed by siphoning.
The newly hatched larvae live for the initial 3 days on their yolk sac.
The actual feeding begins on the 4th day after hatching, when the yolk sac
is resorbed and the digestive organ is formed.
Oyster eggs, rotifers (Braahionus pliaatilis), copepods collected by net, and
nauplius of Artemia salinaare used for feeding individuals in pre larval
stage.
Copepods seem to be a better food than Artemia.
Maximum initial density of pre larvae was 25000/m3 while the density at
harvest was 2000/m3.
Average survival rate at pre larval stage was 10 % Pre larvae hatch at 2.0-2.3
mm total length. They grow to about 6 mm total length in 20days.
29. POST LARVAL STAGE
Post larvae of red sea bream (about 6 mm in total length) are transferred into
net cages installed at sea.
The water depth of the large concrete tanks is decreased to 1/3 (water
volume: 50 m3) before gathering the larvae in order to avoid injury due to
water current.
The nets are cleaned every 2-3 days and replaced every 5 to 10 days. Post
larvae are cultured to fry stage (20-30 mm total length) in the net cages for
about l0-40days.
Initial density of post larvae in the net cages is about 2.000/m3.
The number of fry harvested is about 400-500/m3. Survival rate during net
cage stage is about 30 %.
Survival rate of fry from hatching to 20 mm total length is about 3 %.
Feeding with Braohionus plieatilisand Artemia salinais preferable at the
early stage of the net cages.
But the main feed used during the net cage stage is trash shrimp and fish
flesh.
30. The factors affecting the hatching rate
Water temperature:
The fertilized eggs cease to develop at morula stage at 10° C. The hatching
rate becomes poorer and mortality increases at 25° C. The optimum
incubation temperature ranges from 15.0 to 17.5° C.
Specific gravity:
The fertilized eggs float at the water surface when its specific gravity is
higher than 1.023. They sink under the middle layer when the specific
gravity is lower thanl.023. The hatching rate is 80-98 % for the former case
and 20-50 % for the latter.
Turbidity due to mud:
The effect on the hatching rates of 50 ppm silt in the water is not detectable.
However a decrease in hatching rates' is noticeable at l00 ppm.
Mechanical shocks:
It is important to avoid mechanical shocks such as disturbance and
vibration, as much as possible, when gathering and transferring the eggs.
31. Red seabream, Pagrus major (Temminck and Schlegel, 1843) is a
demersal species that occurs in the northwest Pacific (the northeastern
part of the South China Sea northward towards Japan) at depths
between 10 and 50 m.
The red sea bream, Pagrus major (Chrysophrys major), is one of the
most valuable marine fish in Japan.
This is one of the fish used in aquaculture, and in India its aquaculture
practice is not much developed.
The seeds producing in artificial way is to be more difficult because
of its less survival capacity.
But in artificial way also seed produced, that is by induced method
and environmental manipulation.