the presentation provides the details regarding the murrels or snakeheads which includes the basic taxonomy, some of the important species, distribution, special characters, its aquaculture potential, food and feeding habits, sexual dimorphism, parental care, age at maturity, the maturity stages, breeding season, courtship and mating, natural spawning, fecundity, induced spawning using ovaprim and HCG and LHRHa, and also the detailed facts regarding larval reariing.
Carps form the mainstay of aquaculture in India contributing over 85% of the total aquaculture production There are 61,259 species of vertebrates recognized world; over 30,700 are fish species of which 8,411 ore fresh water while 11,650 are marine. In India 2,163 spp. are fin fishes have been recorded from upland cold water (157; 7.26%) warm water of the plain (54; 20.99%), Brackish water (182; 8.41%) and marine environment (1,370; 63.43%). Some of these species are cultured at commercial level which covering a lot varieties of fin fishes The three Indian major carps, namely Catla (Catla catla), Rohu (Labeo rohita) and Mrigal (Cirrhinus mrigal) contribute the bulk of production to the extent of 75 to85 percent of the total fresh water fish production, the three exotic carp such as Silver carp (Hypophthalmichthys molitrix) and Common carp (Cyprinus carpio ), Grass carp (Ctenopharyngodon idella )form the second important group to incorporate several other medium and minor carp and into the carp poly culture system several method were used because of their region specific consumer preference and higher market demand.
History
Carp culture in India was restricted only to a homestead backyard pond activity in west Bengal and Odisha until late 1950 s with seed from riverine sources as the only input resulting low level of production the technological breakthrough breeding of carp through hypophysation in 1957 freshwater aquaculture of the country the country till 1984 virtually laid the foundation of scientific carp farming in the country.
Important characteristics of Indian major carps:-
Indian major carp grow fast and can reproduce even in artificial ponds. They feed upon phytoplankton, zooplankton, decaying organic matter, aquatic plant etc. stomach is absent in the alimentary canal of the major carps. Three types of Indian major carps are cultured in
Carps form the mainstay of aquaculture in India contributing over 85% of the total aquaculture production There are 61,259 species of vertebrates recognized world; over 30,700 are fish species of which 8,411 ore fresh water while 11,650 are marine. In India 2,163 spp. are fin fishes have been recorded from upland cold water (157; 7.26%) warm water of the plain (54; 20.99%), Brackish water (182; 8.41%) and marine environment (1,370; 63.43%). Some of these species are cultured at commercial level which covering a lot varieties of fin fishes The three Indian major carps, namely Catla (Catla catla), Rohu (Labeo rohita) and Mrigal (Cirrhinus mrigal) contribute the bulk of production to the extent of 75 to85 percent of the total fresh water fish production, the three exotic carp such as Silver carp (Hypophthalmichthys molitrix) and Common carp (Cyprinus carpio ), Grass carp (Ctenopharyngodon idella )form the second important group to incorporate several other medium and minor carp and into the carp poly culture system several method were used because of their region specific consumer preference and higher market demand.
History
Carp culture in India was restricted only to a homestead backyard pond activity in west Bengal and Odisha until late 1950 s with seed from riverine sources as the only input resulting low level of production the technological breakthrough breeding of carp through hypophysation in 1957 freshwater aquaculture of the country the country till 1984 virtually laid the foundation of scientific carp farming in the country.
Important characteristics of Indian major carps:-
Indian major carp grow fast and can reproduce even in artificial ponds. They feed upon phytoplankton, zooplankton, decaying organic matter, aquatic plant etc. stomach is absent in the alimentary canal of the major carps. Three types of Indian major carps are cultured in
This slide is about a pearl spot fish which includes about its habit, habitat ,morphology, food and feeding, breeding behaviour, hatching, larval rearing, embryonic development, nutritive values, farming practices, seed production and pond preparation...
Seed production of giant freshwater prawn fisheries pptAshish sahu
Giant freshwater prawn seed production starts in Andaman - INDIA - A scientist and his team of the Division of Fisheries Science, Central Agricultural Research Institute (CARI), Port Blair, have initiated research on breeding and larval rearing of Giant Freshwater Prawn (M Rosenbergii) under controlled conditions at the CARI farm complex.
A SEMINAR ON INDUCING AGENTS OF HYPOPHYSATIONKartik Mondal
The precise combination of environmental factors required for maturation, ovulation and spawning.
However, quite often, under farm conditions, the requisite environmental factors are either not available or do not persist for sufficient length of time for spontaneous maturation to occur.
The pioneering discovery of B.A. Houssay (1931) and Von Ihering (1935, 1937, Argentina) that fishes can be induced to spawn by injecting pituitary homogenates has somewhat mitigated the problem.
The principal advantage of this technique, referred to in aquaculture parlance as “Hypophysation.”
The transfer of fish seed from the hatchery or place of collection to the rearing pond is called transport of fish seed. The seed fish include fry and fingerlings.
Clarias batrachus, commonly known as the walking catfish or Thai catfish, is a species of air-breathing catfish. Here's some information about the reproduction, breeding techniques, hormonal usage, and related aspects of Clarias batrachus:
1. Sexual Dimorphism: Male and female walking catfish can be distinguished based on certain physical characteristics. Males tend to have a larger size, broader head, and more prominent spines on their pectoral fins compared to females.
2. Breeding Conditions: Walking catfish are known to breed during the rainy season or when there is an increase in water levels. They typically prefer warm water temperatures.
3. Spawning Behavior: Walking catfish are nest builders, and males exhibit paternal care. The male constructs a nest by digging a depression in the substrate, often in muddy areas or among aquatic vegetation.
4. Hormonal Induction: In aquaculture settings, hormonal induction is commonly used to synchronize and stimulate breeding in walking catfish. Hormones like human chorionic gonadotropin (hCG), luteinizing hormone-releasing hormone analogs (LHRHa), or synthetic hormone analogs are used to induce ovulation in females and spermiation in males. The dosage and timing of hormone administration depend on factors such as fish size, maturity, water temperature, and breeding objectives.
5. Breeding Tank Setup: Prepare suitable breeding tanks or ponds for walking catfish reproduction. The tanks should have appropriate water conditions, including a temperature range of 25-30°C (77-86°F), pH around 7, and good aeration to ensure oxygen supply.
6. Hormone Injection: Hormonal injection is typically performed on female walking catfish to induce ovulation. The hormone is administered through intramuscular or subcutaneous injections. It is important to handle the fish carefully during the injection process to minimize stress and ensure proper dosage delivery.
7. Spawning Technique: After hormone injection, the female walking catfish is introduced into the male's nest. The male initiates courtship behavior by circling, nudging, and wrapping his body around the female. This stimulates the release of eggs by the female and sperm by the male for fertilization.
8. Nest Construction and Preparation: Male walking catfish construct nests by excavating depressions in the substrate. They may create tunnels leading to the nest for protection. Nests are usually built in shallow waters, often in muddy areas or among aquatic vegetation.
9. Egg Collection and Incubation: Once the eggs are fertilized, they adhere to the nest walls. The male walking catfish guards the nest and ensures adequate oxygenation of the eggs by fanning them with his pectoral fins. During incubation, maintain suitable water conditions and temperature for the eggs to develop.
Larval Rearing: After hatching, the walking catfish larvae have external gills and can breathe atmospheric air. Provide appropriate rearing conditions, including water quality, temperature.
This slide is about a pearl spot fish which includes about its habit, habitat ,morphology, food and feeding, breeding behaviour, hatching, larval rearing, embryonic development, nutritive values, farming practices, seed production and pond preparation...
Seed production of giant freshwater prawn fisheries pptAshish sahu
Giant freshwater prawn seed production starts in Andaman - INDIA - A scientist and his team of the Division of Fisheries Science, Central Agricultural Research Institute (CARI), Port Blair, have initiated research on breeding and larval rearing of Giant Freshwater Prawn (M Rosenbergii) under controlled conditions at the CARI farm complex.
A SEMINAR ON INDUCING AGENTS OF HYPOPHYSATIONKartik Mondal
The precise combination of environmental factors required for maturation, ovulation and spawning.
However, quite often, under farm conditions, the requisite environmental factors are either not available or do not persist for sufficient length of time for spontaneous maturation to occur.
The pioneering discovery of B.A. Houssay (1931) and Von Ihering (1935, 1937, Argentina) that fishes can be induced to spawn by injecting pituitary homogenates has somewhat mitigated the problem.
The principal advantage of this technique, referred to in aquaculture parlance as “Hypophysation.”
The transfer of fish seed from the hatchery or place of collection to the rearing pond is called transport of fish seed. The seed fish include fry and fingerlings.
Clarias batrachus, commonly known as the walking catfish or Thai catfish, is a species of air-breathing catfish. Here's some information about the reproduction, breeding techniques, hormonal usage, and related aspects of Clarias batrachus:
1. Sexual Dimorphism: Male and female walking catfish can be distinguished based on certain physical characteristics. Males tend to have a larger size, broader head, and more prominent spines on their pectoral fins compared to females.
2. Breeding Conditions: Walking catfish are known to breed during the rainy season or when there is an increase in water levels. They typically prefer warm water temperatures.
3. Spawning Behavior: Walking catfish are nest builders, and males exhibit paternal care. The male constructs a nest by digging a depression in the substrate, often in muddy areas or among aquatic vegetation.
4. Hormonal Induction: In aquaculture settings, hormonal induction is commonly used to synchronize and stimulate breeding in walking catfish. Hormones like human chorionic gonadotropin (hCG), luteinizing hormone-releasing hormone analogs (LHRHa), or synthetic hormone analogs are used to induce ovulation in females and spermiation in males. The dosage and timing of hormone administration depend on factors such as fish size, maturity, water temperature, and breeding objectives.
5. Breeding Tank Setup: Prepare suitable breeding tanks or ponds for walking catfish reproduction. The tanks should have appropriate water conditions, including a temperature range of 25-30°C (77-86°F), pH around 7, and good aeration to ensure oxygen supply.
6. Hormone Injection: Hormonal injection is typically performed on female walking catfish to induce ovulation. The hormone is administered through intramuscular or subcutaneous injections. It is important to handle the fish carefully during the injection process to minimize stress and ensure proper dosage delivery.
7. Spawning Technique: After hormone injection, the female walking catfish is introduced into the male's nest. The male initiates courtship behavior by circling, nudging, and wrapping his body around the female. This stimulates the release of eggs by the female and sperm by the male for fertilization.
8. Nest Construction and Preparation: Male walking catfish construct nests by excavating depressions in the substrate. They may create tunnels leading to the nest for protection. Nests are usually built in shallow waters, often in muddy areas or among aquatic vegetation.
9. Egg Collection and Incubation: Once the eggs are fertilized, they adhere to the nest walls. The male walking catfish guards the nest and ensures adequate oxygenation of the eggs by fanning them with his pectoral fins. During incubation, maintain suitable water conditions and temperature for the eggs to develop.
Larval Rearing: After hatching, the walking catfish larvae have external gills and can breathe atmospheric air. Provide appropriate rearing conditions, including water quality, temperature.
Le diaporama dédié à la culture du milkfish offrira une exploration approfondie des multiples facettes de cette pratique aquacole. En mettant en avant les conditions environnementales optimales, il abordera les techniques de reproduction, les régimes nutritionnels recommandés, ainsi que les défis et avantages inhérents à l'élevage du milkfish. Des visuels graphiques et des images saisissantes seront incorporés pour illustrer de manière vivante le cycle de vie du poisson et dépeindre les installations d'élevage modernes. En parallèle, des données économiques viendront étayer la présentation, mettant en relief l'impact financier de cette activité. L'aspect culturel du milkfish ne sera pas négligé, mettant en lumière son importance dans diverses régions et soulignant son rôle significatif tant sur le plan économique que social. En somme, ce diaporama vise à offrir une compréhension holistique de la culture du milkfish, alliant informations pratiques et perspectives culturelles.
Salient biological characteristics of some selected carps: imran nagarihn FreeStyle Corp.
A very large group of fish native to Europe and Asia.
Carp is a common name for various species of freshwater fish of the family Cyprinidae.
They have been introduced to various locations around the world.
Seed production of Freshwater Prawn.pdfSadia Nabilah
The giant freshwater prawn is the largest and fastest-growing freshwater prawn widely distributed in Indian rivers’ confluent of the sea. The Giant freshwater prawn, M. rosenbergii, has great demand both in national and international markets. It migrates between river and estuary.
National and international scenario of aquafeeds availability demand and supplyAkhila S
,aquafeeds, demand, and supply of aquafeeds ,covid- 19 impact on aquafeed industry ,major market players in the aquafeed market ,scenario of aquafeeds in india ,shrimp industry in india ,farm-made feed industry in india
primary productivity, photosynthesis, the primary producers in the aquatic environment. the factors affecting primary productivity in water, gross and net primary productivity, methods of measuring primary productivity based on measurements of oxygen evoution, carbohydrate estimation and chlorophyll method. the methods include radiocarbon(C14) method, C13 method , dark and light bottle method chlorophyll method, remote sensing and also incubation
Nutritional requirement of larvae and broodstock of commercially important fi...Akhila S
the presentation provides the details regarding, Tthe broodstock nutrition, essential nutrients and recent data on broodstock nutrition; also larval nutrition; the hatchery utilised live feeds in detail and also microparticulate diet, the recent knowlwdge on essential elements amd minerals in larval nutrition, like taurine, phospholipids, liposomes, waxy spray beds etc
the presentation provides the various fungal pathogens of fish and shell fish along with their lifecycles, the pathology, histology, epizootiology, prevention and treatment measures
the presentation provides details regarding the natural and artificial feeds of fishes, purified and semipurified diets, feeds based on the moisture contents, the larval feeds including the most recent spray dried and vacuumdried feeds, microparticulate diets, the microencapsulated, the microcoated and the microbound diets, microextruded marumerisation, and particle associated rotated agglomeration
the presentation deals in detail the taxonomic aspects,the general behaviour and livelihood,centolecithal eggs, developmental aspects, the anatomical parts of the body,spawning activity, male organ called claspers, the developmental stages which include the granulation and degranulation stage, nuclei formation, germ disc formation, germ disc expansion, the limb bud stage followed by the embryonic moult stages, special reference to the trilobate larvae
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
2. INTRODUCTION
Highly regarded food fish in South and
South East Asian Countries
Popular fish for aquaculture since they
breed in confined water bodies.
Aggressive and carnivorous in nature.
Also considered a pest fish since they
destroy other natural species of a
water body where they inhabit.
3. BASIC TAXONOMY
Phylum Vertebrata
Subphylum Craniata
Superclass Gnathostomata
Series Pisces
Class teleostomi
Subclass Actinopterygii
Superorder Ostariophysi
Order Channiformes
Family Channidae(=Ophiocephalidae)
Genus Channa
4. There are about 33 sps of murrels
distributed in tropical Asia including
Northern China and Africa
Species of aquaculture importance:
◦ Channa striatus
◦ C. punctatus
◦ C. marulius
◦ C. maculata
◦ C. micropeltes
10. DISTRIBUTION
The geographic distribution of genus
Channa extends from Amur in eastern
Siberia to China, Korea, India, Burma,
Bangladesh, Afghanistan, Iran,
Srilanka, Thailand, Vietnam,
Kampuchia, Malaysia, Indonesia,
Phillippines, East India and tropical
Africa.
Channa inhabit all type of freshwater
such as rivers, lakes, reservoir, ponds,
swamps, canals, ditch.
11. SPECIAL CHARACTERS
Ability to breathe atmospheric oxygen-
sold alive at high prices in the market
Predacious and cannibalistic
Known to survive drought by
aestivating for months in moist mud
Very hardy and can tolerate
unfavourable conditions.
12. AQUACULTURE POTENTIAL
Most common system of murrel culture is in earthen
ponds ranging in size from 800- 1600m³.
In Vietnam- cultured in cages moored near the shore
or trailed behind fishermen boat
Traditional system- in irrigation wells
High quality flavour and texture of flesh- regarded as
diets for invalids and recuperating patients
Generally monoculture practiced,
◦ In Taiwan, murrels stocked in carp and tilapia ponds to
forage unwanted fishes
◦ In Thailand, integrated culture with pig and poultry
In Thai, farmers stock 75-460 fry of C. striatus per
square metre of pond area
trash fish, rice bran and broken rice are fed thrice
daily in the ratio 8:1:1
13. FOOD AND FEEDING
HABITS
Parameswavaran(1975) has made a detailed
study on the food and feeding habit of C.marulius
in swamps.
He found that post larvae are exclusively
phytophagus, the bulk constituted by
zooplankton and rotifers and also small quantity
of protozoans.
The phytoplankton encountered were desmids
and diatoms.
The large post larvae subsists mainly on small
aquatic insects and other hemipterans.
Aquatic insects predominate the diet of larger
juveniles.
The species develops piscivorous tendency at
this stage.
14. In general, the food and feeding habit of
C.striatus is the same as given murrel.
They are also highly piscivorous, but a lesser
degree than C.marulius.
At 151-250 mm size group, C.striatus
develop piscivorous tendency.
Larger adult are predominating piscivorous
constituting their diet mainly with carp
minnows, weed fish, small sized murrel etc..
True cannibalism is also observed in fry and
juveniles stage.
The feeding intensity decrease with the
increase in size of the fish; more in juveniles
and maximum in adults during maturing and
recovering months.
15. Like other murrels C.punctatus is also a
carnivore, feeding mainly on the animal food
right from the post larval stage, but in
different stages of life different diet have been
noticed.
Spawn and the early fry feed almost
exclusively on zooplankton; juveniles
consume mainly on aquatic insects;
fingerlings feed on bigger sized aquatic insect
and partly shrimps, annelids and small fish
while adult subsists on medium fish fry,
minows, shrimps, worms and insects.
The difference in food habit of the species of
murrels as observed may be attributed to the
variation in the availability of the different food
organisms.
16. SEXUAL DIMORPHISM
SPECIES MALE FEMALE
C.marulius No bulging abdomen.
Vent pale round and
reddish.
Slight bulging of
abdomen.
C.striatus No bulging abdomen.
Vent pale . Anal
papilla-like structure
with its tip pointed.
Slight bulging
abdomen. Vent round
and reddish. Anal
papilla like structure
broad, slightly reddish
in colour and blunt
with reddish dot.
C.punctatus No bulging abdomen.
Numerous minute
black dots on the dark
ventral bands. Vent
oblong and pale with
brown to dark
periphery. A pinkish
Slight bulging
abdomen. Diffused
black blotches. A few
minute black dots may
or may not be present.
Vent round, slightly
protruding and
19. PARENTAL CARE
In Channa marulius, the species exhibits
deep parental care.
They build cup like nests in a weedy
margin by inter weaving act of stem and
blade of weeds.
Both parents guard the egg and fry
although at times only one is seen with
the brood.
Parental care ceases and the young are
disposed when attain a size of above
170mm.
The degree of negligence is inversely
proportional to the size of young one.
21. AGE AT MATURITY
Murrels attain maturity at an age
between one and two years
Length
◦ C. striatus- above 25 cm
◦ C. marulius- above 36 cm
22. MATURITY STAGES
The following six stages of maturity was
observed in the ovary of spotted murrel
23. Stage 1 Ovaries thin, looks ribbon like transparent,
whitish grey in colour. Extends to not even half
the length of coelom.
Stage 2 Ovaries pale yellow, granular in appearance;
becomes slightly thicker and longer. Oocytes
increase in size and show formation of yolk
vesicle in the periphery of ooplasm.
Stage 3 Ovaries yellow, granular in appearance,
increases in length and width, occupying half of
the length of the body cavity. Yolk granules
increases in quantity and passes towards
periphery of ooplasm.
Stage 4 Ovaries enlarge in girth and length; occupy
almost entire length of coelom. Ova closely
packed, nuclear content not visible.
Stage 5 I. Ovaries attain maximum volume; ova
transparent with large yolk granules.
II. Volume is reduced; extrusion of some ova.
Stage 6 Spent ovaries shrunken; reddish in colour
occupying 3/4th length of coelom.
25. BREEDING SEASON
Peak breeding season of C. striatus is during
the rainy season, but the species seem to
breed throughout the year
the moderate climate and abundant rainfall in
peninsular India provide favourable
conditions for breeding of murrels throughout
the year
In north, these conditions prevelant only for
limited period- breeding restricted to
monsoon and post monsoon
spawns in a variety of habitats such as
rivers,lakes, reservoirs, swamps, jheels,
bheels, tanks,ponds, paddy fields and even
puddles
26. COURTSHIP AND MATING
An elaborate courtship with males actively
chasing the females precedes spawning
Only one male pairs with the female
intense male competition inherent in group
spawning.
The absence of breeding behavior from any
of the breeders often results in spawning
failure
Several factors like body size, pigmentation,
age, and social dominance, environmental
conditions, mating history, female
reproductive state, male dominance and
aggression are known to affect the mating
behavior of fishes in many species
28. NATURAL SPAWNING
In Channa striatus,
Construct a nest with its tail at the edge
of tanks, bites off weeds which grows in
them
The species generally lays its eggs in
shallow margins of weed infested waters
where the weeds are cleared in a small
circular area, probably during active
spawning movement of the breeders
weeds help to hold the floating eggs
together without dispersal.
Also found to breed in weed free waters
and even puddles
29. Both parents guard the egg and larvae
fertilization external
Fry move in shoals near the water
margin
Parental care ceases when they attain
a size of 57mm- young ones disperse
fry and fingerlings frequent the surface
and column
juveniles are column and shallow
bottom dwellers.
30. FECUNDITY
few hundreds to a few thousands,
depending on the size of the fish
vary between 2200 and 34,000 among
cultivated murrels
Fecundity differs in different agro climatic
region as well as habitat
eggs are free floating, spherical and non-
adhesive and have an oil globule.
Are golden yellow in colour in fresh
condition
32. INDUCED SPAWNING
Hypophysation,- natural and synthetic
hormones
using carp pituitary glands
◦ injected intramuscularly in the dorsolateral region
in two instalments
◦ An initial dose of gland varying from 2 to 20 mg/
kg weight of fish was administered to the female
◦ Nil to 20 mg to the males
◦ After 4 to 6 hr a higher dose ranging from 5 to
380 mg/kg was given to the females and 5 to
250mg to the males
Disadvantage- gonadotropic potency of
pituitary glands used is unknown and difficult
to standardise
33. Ovaprim hormone
◦ Single dosage
◦ Mass induced breeding
◦ Brood stocks were injected with dosage of
0.5 ml/kg body weight
◦ spawning occurred within 24-26 h,
following the injection with the hormon
Human Chorionic Gonodotrophin
(HCG) and LHRHa also used for
induced spawning
35. LARVAL REARING
Captive reproduction and larval rearing of
snakehead have been accomplished
experimentally, but are not done on a
commercial scale
The hatchling, according to Alikunhi (1953),
measures 4.33 mm in length.
The yolksac is fully absorbed on the third day
At this stage the post-larva has a well formed
mouth and has commenced feeding
Pronounced cannibalism is observed during
fry and juvenile stages(minimised in captive
stocks by ensuring abundant supply of
preferred food
36. The life cycle of any species of fish
from hatchlings to fry/fingerlings stage
have high mortality
Early fry subsists mainly on
zooplankton, it is better to feed them
with small plankton like rotifers and
Artemia nauplii
Fingerlings – insect larvae, fish fry,
zooplankton
37. fed with a supplementary feed
comprising of fish meal (50%) and
mustard oilcake (50) at the rate of 5-
8% of theestimated body weight.
39. PAPERS
Induced spawning of the striped murrel
Channa striatas using pituitary extracts,
human chorionic gonadotropin, luteinizing
hormone releasing hormone analogue, and
ovaprim- Mohamed A. Haniffa, Thangarose
Merlin, Junaith Shaik Mohamed; Acta Icht.
Piscat. 30 (1): 53-60, Ann. 2000
Effect of Different Synthetic Hormones and/or
Their Analogues on Induced Spawning in
Channa marulius-Muhammad Hafeez-ur-
Rehman,1 Muhammad Ashraf, 1 Farzana
Abbas, 1 Khalid Javed Iqbal, Iftikhar Ahmed
Qureshi and Syedah Andleeb; Pakistan J.
Zool., vol. 47(3), pp. 745-752, 2015.
