Reproduction is a fundamental biological process which enables continuation of species. In fisheries biology, reproduction assumes greater significance to understand sexual
dimorphism, process of maturation, size or age of maturity, breeding season, spawning area, sexual segregation, migration, fecundity, embryonic and larval development and
recruitment. Most of the management strategies in capture fisheries are based on reference points that are the manifestations of reproductive biology. In aquaculture,
knowledge of reproductive biology of a fish is essential for hatchery production of fish feeds.
,
Nazmul Haque Syekat
Modern developments in transport technology are from two levels; one is from an understanding of internal physiological mechanisms of the fish and the optimal requirements, ensuring maximum survival of fish under transport and the other is from a study of the environmental parameters of the medium in which fish are transported. Under anaesthesia fish can be transported without water even, provided the skin and gills are kept moist under low temperature. The cryopreservation of fish sperm for use at any convenient time can be referred to here, though this would concern seed production more directly than live seed transport.
it is about endocrine glands of the fishes ,like the pituitary gland, thyroid gland, adrenal gland, the corpuscles of stannius ,the ultimobranchial gland , urohypophysis, pancreatic islet
pineal organ
Modern developments in transport technology are from two levels; one is from an understanding of internal physiological mechanisms of the fish and the optimal requirements, ensuring maximum survival of fish under transport and the other is from a study of the environmental parameters of the medium in which fish are transported. Under anaesthesia fish can be transported without water even, provided the skin and gills are kept moist under low temperature. The cryopreservation of fish sperm for use at any convenient time can be referred to here, though this would concern seed production more directly than live seed transport.
it is about endocrine glands of the fishes ,like the pituitary gland, thyroid gland, adrenal gland, the corpuscles of stannius ,the ultimobranchial gland , urohypophysis, pancreatic islet
pineal organ
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.
cryopreservation of fish gametes NBFGR gene bankAshish sahu
Cryopreservation of reproductive products of many aquatic species has been successfully achieved. ... Cryopreservation technology applied to the preservation of fish gametes in aquaculture plays an important role in seed production, genetic management of broodstock and conservation of aquatic resources
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Phone: 9010705687
Fishing gears are defined as tools used to capture marine/aquatic resources, whereas how the gear is used is the fishing method.
Traps are fishing devices into which fish or shellfish are enticed by bait or shelter spaces or enclosures where they are guided to enter, because of an obstacle placed in their normal migration path and from which their escape is made difficult by constriction, retarding valves or labyrinths.
Trap fishing is a passive fishing technique of ancient origin. There is extraordinary variety in their design, fabrication and operation.
The cold water fisheries deal with fisheries activity in water where temperature of water ranges from 5 to 25 degrees centigrade. The water temperature under cold water fisheries should not be more than 25°C even in summer. Such conditions in India occur in Himalayan and peninsular regions.
9 Finest Coldwater Aquarium Fish
Orangethroat Darter.
Three-Spined Stickleback.
Orange-Spotted Sunfish.
Diamond Sturgeon.
Siberian Sturgeon.
Sterlet.
Fathead Minnow.
Southern redbelly dace.
Tench.
Rosy Barb. Hailing from Afghanistan and Bangladesh, this little fish is tolerant of temperatures in …
Gold Barb. The gold bard, or Chinese barb, is an extremely popular cold-water fish. Any aquarium …
Two Spot Barb. This fish hails from Nepal, India, and Pakistan. The omnivorous two spot barb …
Bloodfin Tetra. Natives to Southern Brazil and Paraguay, both the standard bloodfin .
Coldwater fish in terms of the aquarium trade refers to any fish species that prefer cooler water temperatures. The optimal temperatures for these fish hover around the 68-degree mark, although each species’ temperature range may vary from the norm.
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.
cryopreservation of fish gametes NBFGR gene bankAshish sahu
Cryopreservation of reproductive products of many aquatic species has been successfully achieved. ... Cryopreservation technology applied to the preservation of fish gametes in aquaculture plays an important role in seed production, genetic management of broodstock and conservation of aquatic resources
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Phone: 9010705687
Fishing gears are defined as tools used to capture marine/aquatic resources, whereas how the gear is used is the fishing method.
Traps are fishing devices into which fish or shellfish are enticed by bait or shelter spaces or enclosures where they are guided to enter, because of an obstacle placed in their normal migration path and from which their escape is made difficult by constriction, retarding valves or labyrinths.
Trap fishing is a passive fishing technique of ancient origin. There is extraordinary variety in their design, fabrication and operation.
The cold water fisheries deal with fisheries activity in water where temperature of water ranges from 5 to 25 degrees centigrade. The water temperature under cold water fisheries should not be more than 25°C even in summer. Such conditions in India occur in Himalayan and peninsular regions.
9 Finest Coldwater Aquarium Fish
Orangethroat Darter.
Three-Spined Stickleback.
Orange-Spotted Sunfish.
Diamond Sturgeon.
Siberian Sturgeon.
Sterlet.
Fathead Minnow.
Southern redbelly dace.
Tench.
Rosy Barb. Hailing from Afghanistan and Bangladesh, this little fish is tolerant of temperatures in …
Gold Barb. The gold bard, or Chinese barb, is an extremely popular cold-water fish. Any aquarium …
Two Spot Barb. This fish hails from Nepal, India, and Pakistan. The omnivorous two spot barb …
Bloodfin Tetra. Natives to Southern Brazil and Paraguay, both the standard bloodfin .
Coldwater fish in terms of the aquarium trade refers to any fish species that prefer cooler water temperatures. The optimal temperatures for these fish hover around the 68-degree mark, although each species’ temperature range may vary from the norm.
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.
AGE AND GROWTH OF THE ANTARCTIC FISH Chaenocephalus aceratus based on OTOLITH weight, microstructure and TL frequency; some relations with Pseudochaenichthys georgianus.
An oil spill is a release of crude oil or refined petroleum products into the environment, such as oceans, rivers, lakes, or land. Oil spills can be caused by a variety of factors, including accidents during transportation, storage, or drilling operations, natural disasters such as hurricanes or earthquakes.
The primary productivity of phytoplankton, macroalgae, and seagrasses forms the base of marine ecosystem structuring in aquatic environments. Primary productivity is affected by various environmental factors and ecological processes that usually interact in a complex manner. The rate of primary production usually governs the overall ecosystem health and ecological productivity of a water body, and any observed trends may reveal the occurrence of potential stresses on existing ecosystems. Along the Saudi Gulf coast, primary productivity monitoring may help provide the basis for identifying the potential stressors to the coastal marine environments. Foremost among the considerations is the potential adverse effect of excessive anthropogenic nutrient loadings, which may lead to eutrophication events that can adversely impact on ecosystem health. In addition, high nutrient loads from man-made activities may trigger the excessive growth of some toxic phytoplankton species, potentially resulting in harmful algal blooms (HABs) with serious human health risks and negative economic impacts.
This study is geared towards monitoring the primary productivity levels in selected areas of the Saudi Gulf waters to identify areas of concern as regards hyper-nutrification, ecological disturbance, and potential hot spots for HAB events. Nutrient loadings and the identification of potential HAB organisms will form a special focus of the investigations.
Carbon is an essential element for all life forms on Earth. Whether these life forms
take in carbon to help manufacture food or release carbon as part of respiration, the
intake and output of carbon is a component of all plant and animal life.
The carbon cycle is vital to life on Earth. Nature tends to keep carbon levels balanced,
meaning that the amount of carbon naturally released from reservoirs is equal to the
amount that is naturally absorbed by reservoirs. Maintaining this carbon balance
allows the planet to remain hospitable for life. Scientists believe that humans have
upset this balance by burning fossil fuels, which has added more carbon to
the atmosphere than usual and led to climate change and global warming.
Not only fish but also all animals, must obtain oxygen from the environment for respiration. Oxygen is far less available to aquatic organisms than it is to air-breathers, and the dissolved oxygen content of water may limit the activities of fish. In most natural waters, the supply of oxygen to water (diffusion from the atmosphere and production from underwater photosynthesis) exceeds the amount used in oxygen-consuming processes, and fish seldom have problems obtaining enough oxygen to meet normal metabolic demands.
In aquaculture ponds, however, the biomass of plants, animals and microbes is much greater than in natural waters, so oxygen is sometimes consumed faster than it is replenished. Depending on how low the dissolved oxygen concentration is and how long it remains low, fish may consume less feed, grow more slowly, convert feed less efficiently, be more susceptible to infectious diseases, or suffocate and die. Aqua culturists avoid these problems by aerating ponds mechanically to supplement normal oxygen supplies.
Global production from aquaculture is growing substantially and provides increasingly significant volumes of fish and other aquatic food for human consumption, a trend that is projected to continue. Although aquaculture growth has potential to meet the growing need for aquatic foods and to contribute to food security, poverty reduction and, more broadly, to achieving sustainable development and the Millennium Development Goals, it is increasingly recognized that improved management of the sector is necessary to achieve this potential. The application of certification in aquaculture is now viewed as a potential market-based tool for minimizing potential negative impacts and increasing societal and consumer benefits and confidence in the process of aquaculture production and marketing
Whiteleg shrimp (Litopenaeus vannamei, formerly Penaeus vannamei), also known as Pacific white shrimp or King prawn, is a variety of prawn of the eastern Pacific Ocean commonly caught or farmed for food.L. vannamei is a decapod crustacean which is native to the Eastern Pacific Coast of Central and
South America from Tumbes, Peru in the south to Mexico in the north. It has been introduced widely around the world since the 1970s, but especially since 2000, as it has become the principle
cultured shrimp species in Asia. The species itself is not considered a major threat to biodiversity, does not appear to have formed breeding populations, and has generally resulted in positive economic impacts in non-indigenous areas. An examination of current lists of invasive species
published by the International Union for Conservation of Nature’s Invasive Species Specialist Group (IUCN, 2004) revealed no listings for L. vannamei. As mentioned, L. vannamei has been anthropogenically introduced as an aquaculture species to several areas of the world to which it is
not native.
,
Nazmul Haque Syekat
Haploids are individuals that have only a single set of chromosomes. Because they have only a single set of chromosomes, every detrimental allele will be expressed, since none will be hidden by a dominant allele in the heterozygous condition. As such, it is doubtful that many haploids will survive very long. Haploid medaka , common carp , masu salmon , rainbow trout , Atlantic salmon , chum salmon and plaice have been produced for experimental purposes, but none lived long.
The government of Bangladesh has formulated the Government Water Resources Management Policy, 2009 in the public interest with a view to giving priority to the provision of settlements in favor of real fishermen and conservation of biodiversity including conservation of fishery resources and increase in production.
Blue Economy means sustainable use of ocean resources for economic growth, improved livelihoods and jobs, and ocean environment health. More specifically, it basically refers to any economic activity in the marine sector, whether sustainable or not”.In Bangladesh , Coastal and Marine based aquaculture has been developed day by day .There are many prawn and shrimp farm in Bangladesh among the different districts.These farm play a dominant role for rising blue economic development of Bangladesh .Besides sea weed is also a prominent aquaculture in Bangladesh .There are about 133 species of sea weeds that commercially produce in different kinds of farm in Bangladesh .Although there has so many bar to management theses types of farm ,but day by day the efficiency of producing these product are increasing very rapidly. A very great role has kept by the marine and coastal aquaculture for developing blue economy of Bangladesh
Inbreeding is the production of offspring from the mating or breeding of individuals or
organisms that are closely related genetically.By analogy, the term is used in human
reproduction, but more commonly refers to the genetic disorders and other consequences that
may arise from expression of deleterious or recessive traits resulting from incestuous sexual
relationships and consanguinity. Inbreeding results in homozygosity, which can increase the
chances of offspring being affected by deleterious or recessive traits.This usually leads to at least
temporarily decreased biological fitness of a population(called inbreeding Common fruit fly
females prefer to mate with their own brothers over unrelated males. depression), which is its
ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially
referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by
inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing.
Crossbreeding between populations also often has positive effects on fitnessrelated traits, but
also sometimes leads to negative effects known as outbreeding depression. However increased
homozygosity increases probability of fixing beneficial alleles and also slightly decreases
probability of fixing deleterious alleles in population. Inbreeding can result in purging of
deleterious alleles from a population through purifying selection.
Bangladesh , the largest delta on earth, is situated
in South Asia. It is located between 20°
34′ and
26°
38′ north latitude and 88°
01′ and 92°
41′ east
longitude. It is bordered by India on the west,
north, and east, by Myanmar on the southeast, and
by the Bay of Bengal on the south. The area of the
country is 147,570 km2
. Most of the country is
low-lying comprising mainly the delta of the
Ganges and Brahmaputra rivers. A total of 80% of
the country is floodplain . The environment of the
country is under severe pressure due to changing
climate and destructive anthropogenic activities.
Environmental degradation is directly and
indirectly affecting human health, ecosystems
, and economic growth of the country. Demographic pressure, poverty,lack of proper
awareness on environmental issues, and lack of implementation and monitoring of
environmental rules are the main causes for existing environmental condition of
Bangladesh. The climatic condition of Bangladesh is tropical monsoon. The country
currently faces several environmental issues which threaten these resources, including
groundwater metal contamination, increased groundwater salinity, cyclones and flooding, and
sedimentation and changing patterns of stream flow due to watershed mismanagement. Some
of these, such as the changing patterns of stream flow and presence of lead in groundwater,
can be directly correlated with human activity and industrial processes, while others, such as
cyclones and flooding are naturally occurring issues.
Geographic environment is that part of the terrestrial natural environment
that has been to some extent altered by human beings and which at the
present moment is directly connected with the life and production activity
of society. The natural objects and the phenomena related to them which
surround men constitute the geographical environment. (eg. surface of the
earth, minerals, water, animals, mountains, plants, sun, moon, plains.) The
geographic environment is one of the permanent and necessary conditions
for the development of society. It can accelerate or retard this development,
but it is not the main moving force of society’s development, since the
specific laws of the movement of nature and society, as well as the rates of
movement (changes), are essentially different.
Social impact assessment (SIA) includes the processes of analyzing, monitoring and managing
the intended and unintended social consequences, both positive and negative, of planned
interventions (policies, programs, plans, projects) and any social change processes involved by
those interventions ( According to the International Association for Impact Assessment).In case
of fisheries science Social Impact Assessment is a method of gauging the social and cultural
consequences of alternative fishery management actions or policies. The purpose and logic of the
SIA are the same as those for the economic and ecological elements of environmental impact
analysis and assessment. An impact assessment determines (social/cultural) conditions in areas
or populations likely to be affected by the regulatory action or policy; projects future effects of
continuing the status quo; and then estimates effects, relative to the status quo, that will result on
local, regional, and national scales if reasonable fishery management alternatives are
implemented.
Fish diseases affect the survival and growth rates of fìsh under culture. Given that drug
treatments are expensive, fìsh diseases invariably lead to lower harvest and higher cost.
Fish farmers often suffer hefty economic losses due to fìsh diseases.To alleviate such losses,
it is crucial to take precautions to prevent fìsh diseases and reduce pathogen levels in water
bodies. It is also important to prevent water quality from deteriorating and to strengthen
the natural resistance of the fìsh stock. Regular monitoring of fìsh health is an effective way
to identify disease causes and appropriate treatments. One major cause of serious fìsh kill
is overlooking the contagiousness of fìsh diseases and thus delaying treatment. As such,
adequate care and treatment should be given to infected fish promptly.
,
Nazmul Haque Syekat
Syekat
Four fishing grounds have been identified so far. They are south patches, south of south patches, middle ground and Swatch of no Ground.This slide will show you about the different fishing site in bay of bengal where the abundance of fish is higher than other areas.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Breeding Biology & Parameters of Finfish and Shellfish by Syekat
1. Course Title : Fish Hatchery Operation and Management
Course Code : FIMS 3209, Year 3 Term 2
An Assignment On : “Breeding Biology & Parameters of Finfish and
Shellfish”
Submitted to Submitted by
Dr. Shyamal Kumar Paul
Assistant Professor ,
Department of Fisheries & Marine
Science , Noakhali Science & Technology
University
Nazmul Haque Syekat
Roll: ASH1802050M
Department of Fisheries & Marine
Science , Noakhali Science &
Technology University
Date of Submission : 12th April 2021
Noakhali Science & Technology University
Sonapur, Noakhali -3814
Department of Fisheries and Marine Science
2. 2 | P a g e
INDEX OF THE ASSIGNMENT
SL NAME OF CONTENTS PAGE
1 Introduction 3
2 What is Fin fish ? 3
3 What is Shell fish ? 4
4 Breeding Biology and Parameters of Finfish 6
5 Reproductive Biology of IMC’s 14
6 Breeding Biology of Penaeid Shrimps and Prawns: 15
7 Breeding Biology of Crabs 21
8 Reproductive Biology & Physiology of Lobsters: 24
9 Conclusion 25
10 References 26
3. 3 | P a g e
Breeding Biology and Parameters of Finfish and Shellfish
Introduction:
Reproduction is a fundamental biological process which enables continuation of species. In
fisheries biology, reproduction assumes greater significance to understand sexual
dimorphism, process of maturation, size or age of maturity, breeding season, spawning
area, sexual segregation, migration, fecundity, embryonic and larval development and
recruitment. Most of the management strategies in capture fisheries are based
on reference points that are the manifestations of reproductive biology. In aquaculture,
knowledge of reproductive biology of a fish is essential for hatchery production of fish
feeds.
What is Fin fish ?
Fins are usually the most distinctive anatomical features of a fish. They are composed of
bony spines or rays protruding from the body with skin covering them and joining them
together, either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as
seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with
the spine and are supported only by muscles. Their principal function is to help the
fish swim.
Fig : Ray fins on a teleost fish, Hector's lanternfish (1) pectoral fins (paired), (2) pelvic fins (paired),
(3) dorsal fin, (4) adipose fin, (5) anal fin, (6) caudal (tail) fin
4. 4 | P a g e
Fins located in different places on the fish serve different purposes such as moving
forward, turning, keeping an upright position or stopping. Most fish use fins when
swimming, flying fish use pectoral fins for gliding, and frogfish use them for crawling. Fins
can also be used for other purposes; male sharks and mosquitofish use a modified fin to
deliver sperm, thresher sharks use their caudal fin to stun prey, reef stonefish have spines
in their dorsal fins that inject venom, anglerfish use the first spine of their dorsal fin like a
fishing rod to lure prey, and triggerfish avoid predators by squeezing into coral crevices
and using spines in their fins to lock themselves in place.
What is Shellfish ?
Shell fish is a colloquial and fisheries term for exoskeleton bearing aquatic invertibrates
used as food,including various species of molluscs,crustacean and echinoderms.Although
most kind of shellfish are hervested from salt water environments,some are found in fresh
water.In addition ,a few species of land crabs are eaten for example Cardisoma guanhumi in
the Caribbean. Shellfish are among the most common food allergens.
Fig: Marine Shirmp & fresh water prawn
Despite the name, shellfish are not fish. Most shellfish are low on the food chain and eat a
diet composed primarily of phytoplankton and zooplankton. Many varieties of shellfish,
and crustaceans in particular, are actually closely related to insects and arachnids;
crustacean make up one of the main subphyla of the Arthopoda .Molluscs include
cephalopods (squids, octopuses, cuttlefish) and bivalves (clams, oysters), as well
5. 5 | P a g e
as gastropods (aquatic species such as whelks and winkles; land species such as snails and
slugs). Molluscs used as a food source by humans include many species of
clam,mussels,oysters, winkles, and scallops. Some crustaceans that arecommonly eaten
are shrimp, lobsters, crayfish, and crabs. Echinoderms are not as frequently harvested for
food as molluscs and crustaceans; however, sea urchin roe is quite popular in many parts of
the world, where the live delicacy is harder to transport.
Fig ; Some Examples of shellfish
6. 6 | P a g e
Breeding Biology and Parameters of Finfish
1.Natural breeding of finfishes :
Most teleosts are seasonal breeders and their spawning coincides with seasonal
changes in environmental factors.
In response to environmental stimuli, the hypothalamus secretes a hormone termed
as releasing hormone (RH).
The Nucleus Lateralis Tuberis (NLT) of the hypothalamus responds to an electrical
signal from the brain by secreting RH at the end of the axon; thus an electric signal
becomes a chemical one (bridging the gap between nervous/neural and hormonal
information).
The arrangement of these neurons/axons is unique in teleosts, their axon directly
end on gonadotropic cells in the adenohypophysis, but do not secrete their
hormones into a portal blood system.
However, the effect of RH is to stimulate the production of Gonadotropic hormone
(GtH) and its subsequent release into the vascular system of the adenohypophysis.
GtH is then carried in the general blood circulation to the gonads which in turn
secrete steroids which are required for final maturation and spawning.
The chain of events leading from the reception of environmental stimuli to maturation and
release of gametes is as follows:
7. 7 | P a g e
2.Sexual maturity
Maturation of fish gonads (gonadal maturation) is a process by which minute sex
cells (germ cells) develop, with accessory tissues, into large organs (testis and
ovary) which finally lead to the maturation and release of gametes (sperm and
eggs).
Maturation may occur once in the life spawn of a fish or once a year or many times a
year, depending on species and conditions.
Age at sexual maturity in fish varies with climatic and ecological /environmental
conditions. It varies between species and between sexes. In general, males mature
earlier than females.
Size at first sexual maturity also varies with species and between sexes.
3.Breeding season
The cultivated carps (with the exception of common carp) attain maturity at the end
of second year or the beginning of third year, depending upon the temperature.
They mature during May-June and some are found to remain mature till the end of
August.
Majority of the major carps breed during south-west monsoon, in flooded rivers.
The common carp attains maturity at 4-6 months of age and breed year-round in
captivity.
Like the common carp, tilapia matures at 4-5 months and spawns through out the
year.
Medium carps, catfishes, murrels, etc. mature during pre-monsoon and with the
onset of South-West monsoon and breed in ponds, tanks, paddy fields, etc.
Brackish-water and marine fishes attain maturity during pre-monsoon and with the
onset of South-West monsoon and have prolonged breeding season.
Gonadotropins regulate the formation and maturation of gametes indirectly through
steroid hormones produced by gonad itself.
8. 8 | P a g e
Although there are rare cases of parthenogenesis, such as in the Amazon molly (Poecilia
formosa), the large majority of teleosts reproduce through sexual reproduction.
4.Number of Breeding Opportunity
Synchronous: Synchronous fish reproduce only once each year, or once in their lifetime. In
such species, all oocytes develop simultaneously and are at the same developmental stage
at a given time. This is the case for salmonids, for example. Eggs are spawned and the fish
dies -Pacific salmon
Group synchronous: Group synchronous fish have two or more distinct populations of
oocytes present at the same time and ovulate once in a season, or undergo multiple
ovulations over a few days or weeks within the spawning season.-Most species of fish
Asynchronous: Asynchronous fish, such as the zebrafish, are capable of ovulating on a
regular basis, sometimes every day, over a prolonged period.
5. Size and Age at First Maturation
Under different geographical and ecological conditions, the maturity age of the same
species is widely different. The maturity age of common carp is one year, for gross carp and
silver carp 2+ years and in case of Indian major carps such as Mrigal and Rohu the maturity
age is 1+ years while for catla 2+ years. However, in the same region maturity age varies
somehow rather with ecological conditions and other intrinsic factor. The induced breed
species reared in pond culture practice gets early maturity than the natural riverine stock.
Generally males mature little earlier than the female, in cultivable carps.
6. Time of Spawning and Duration/Season of Reproduction
The regular monsoon season (July-August) is the breeding season for the 5 cultivable carps
viz., Catla, Rohu, mrigal, silver carp and grass carp, in most part of India. However, the
season may begin a few months earlier or last longer depending upon the setting in of the
monsoon season, early or late in respective regions of the country, e.g. the breeding season
for carp’s starts earlier in Assam than in Orissa or Bengal. All the above carp species are
9. 9 | P a g e
more difficult to spawn than common carp. The common carp breeds in ponds and has two
breeding seasons on the plains of India viz. monsoon and post-winter period i.e. Feb. -
March. The major Indian and Chinese carps breed naturally in flooded river conditions
during monsoon in their native countries and this is also the suitable season for taking up
the induced breeding operation.
CARPS (IMC): April to Sept. – During monsoon
Common carp: 1-Feb-March; 2-August-sept
Grass & Silver carp: April to Sept. – During monsoon
Catfish(s) : During monsoon period
7. Type of Spawning
Open substrate spawner
Pelagic spawner: Benthic spawner:
A species that sheds pelagic eggs into the
water column .The eggs, embryos and larvae
of pelagic spawners contain oil globules or
have a high water content. They are usually
pelagic fish such as tuna and sardines. Some
demersal fish leave the bottom to spawn
pelagically, particularly coral reef fish such
as parrotfish .
Benthic spawners deposit their spawn on or
near the bottom. They are usually demersal
fish such as cod and flatfish
Brood hider
Brood hiders hide their eggs but do not give parental care after they have hidden them.
Brood hiders are mostly benthic spawners that bury the fertilized eggs. For example,
among salmon and trout the female digs a nest with her tail in gravel. These nests are
called redds. The female then lays her eggs while the male fertilizes them, while both fish
defend the redd if necessary from other members of the same species. Then the female
10. 10 | P a g e
buries the nest, and the nest site is abandoned. Annual killifish known as egg buriers lay
their eggs in mud. The parents mature quickly and lay their eggs before dying when the
water dries up. The eggs remain in a dormant stage until rains stimulate hatching.
Bearers
Bearers are fish that carry their embryos around with them, either externally or internally.
External bearers:
Mouth brooders - carry eggs or larvae in their mouth. Mouth brooders can be ovophiles or
larvophiles. Ovophile or egg-loving mouth-brooders lay their eggs in a pit, which are
sucked up into the mouth of the female. The small number of large eggs hatch in the
mother's mouth, and the fry remain there for a period of time. Fertilization often occurs
with the help of egg-spots, which are colourful spots on the anal fin of the male. When the
female sees these spots, she tries to pick up the eggspots, but instead gets sperm that
fertilizes the eggs in her mouth. Many cichlids and some labyrinth fish are ovophile
mouthbrooders. Larvophile or larvae-loving mouth-brooders lay their eggs on a substrate
and guard them until the eggs hatch. After hatching, the female picks up the fry and keeps
them in her mouth. When the fry can fend for themselves, they are released. Some
eartheaters are larvophile mouthbrooders.
Internal bearers:
The shorter times spwans are characteristic of species that eventually deposit their
embryos in the environment, surrounded by a horny capsule; whereas the longer periods
are characteristic of sharks that retain the embryos until they are ready to emerge as
actively swimming young. Fishes can be classified in to 5 groups on the basis of spawning.
Lithophils: Fishes which spawn on hard stony surface eg. Salmon.
Phytophils: Fishes which lag eggs among aquatic plants e.g. carp (Common carp)
Psammophils: Fishes which deposit eggs in sandy surface e.g. Loach.
Ostracophils: Fishes which deposit eggs inside a bivalve e.g. Chilogolsio.
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Pelagophils: Fishes which spawn freely in column of water and the eggs float (cod
fish)
8. Mating System
Promiscuous mating system : Promiscuous is a mating system where both sexes have
multiple partners during the breeding system (e.g. Herring, Cod). In fishes, this is the most
common mating system. Breeders make little or no mate choice and spawn with multiple
partners, either sequentially or at the same time.
Polygamous mating system: Polygamous is a mating system in which an individual of one
sex has multiple partners during the breeding system but individuals of the opposite sex
have only one partner (e.g. Sunfish, tilapia, catfish). Evolutionarily, these systems are
purported to have an increased chance of passing on “good genes” from individuals that
compete for the ability to mate with multiple partners. This mating system can occur with
one male and many females (polygyny) or one female and multiple males (polyandry)
9.Gender System
Gonochoristic: In biology, gonochorism or unisexualism or gonochory describes the state
of having just one of at least two distinct sexes in any one individual organism. The term is
most often used with fish, in which the individual are often gonochorous.
Hermaphroditic: Fish that, when mature, possess both male (testes) and female (ovary)
sex glands at the same time. In such species cross-fertilization can occur during spawning.
Most Serranidae (sea perches) are females first or have both sets of glands equally
developed. Sex may change after maturation (e.g. Sea bream)
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10.Spawning Site Preparation
No preparation; most spp. of broadcast spawners
Site preparation and defended; Tilapia, salmons
11. Place of Fertilization
External: External fertilization usually occurs in aquatic environments where both eggs
and sperm are released into the water. After the sperm reaches the egg, fertilization can
then take place. Most external fertilization happens during the process of spawning where
one or several females release their eggs and the male(s) release sperm in the same area, at
the same time.
Internal: Internal fertilization occurs most often in landbased animals, although some
fishes also have internal fertilization. There are three ways that offspring are produced
following internal fertilization: oviparity, ovoviparity, and viviparity.
Oviparity: Ovuliparity means the female lays unfertilized eggs (ova), which are externally
fertilized.Examples of ovuliparous fish include salmon, goldfish, cichlids, tuna and eels. In
the majority of these species, fertilisation takes place outside the mother's body, with the
male and female fish shedding their gametes into the surrounding water.
Ovoviviparity: In ovoviviparous fish the eggs develop inside the mother's body after
internal fertilisation but receive little or no nourishment directly from the mother,
depending instead on a food reserve inside the egg, the yolk. Each embryo develops in its
own egg. Familiar examples of ovoviviparous fish include guppies, angel sharks, and
coelacanths.
Viviparity: Viviparity occurs in some Sharks and Surf - perches. Similar to ovoviviparous
fish, internal fertilization and development occurs. However, the embryos receive direct
nourishment from the mother, similar to the development of an embryo in mammals. Like
ovoviviparous fish, the viviparous fish give birth to live young, however viviparous fish are
fully advanced at birth allowing for a greater chance of survival
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12. Mechanism of Hatching
There are two mechanisms involved in hatching such as: (a) mechanical hatching and (b)
enzymatic hatching
A. Mechanical Hatching: The mechanical hatching is a process in which egg envelopes are
broken down primarily by mechanical action such as pressure exerted from within or
mastication by the embryo itself.
B. Enzymatic Hatching: In enzymatic hatching emergence of young occurs after
dissolution or softening of egg envelope by the enzymes secreted by the embryo. This
enzyme is called hatching enzyme. These enzymes are secreted into the perivilelline fluid at
the time of hatching from the hatching gland cell located in the epidermis of the embryo.
13. Parental Care
Parental care is a very important adaptation among fishes for ensuring the survival of their
offspring. The parent fish stock look after their offspring during their most critical stage of
life when they are defenseless and very sensitive parental care is of two types: Passive care
(ii) Active care.
(i) Passive care: This is actually the hereditary foresight of the female to provide more
yolk for embryo to sustain life for a long time or to place the eggs on such sites where the
optimum environmental conditions are met and beyond the reach of enemies. Some fish
have in their eggs a poisonous substance which keeps predators away e.g. all major carps.
Fish with passive care have high number of eggs .
(ii) Active care:In active parental care either one or both of the parents take an active part
in carrying for and defending their eggs, larvae and sometimes the fry as well. This
includes the selection and preparation of a suitable place for depositing the eggs, selection
of a good substrate to which the eggs can adhere, collection of nest making material and
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preparation of the nest e.g. Tilapia, fighter etc. Fish with active care have normally less no.
of eggs.
Reproductive Biology of IMC’s
Sexuality: All the major carps species are bisexual (hetro-sexual) and sex can be
distinguished only during the breeding season. The identifying features between sexes are
related to the length and texture of pectoral fin, condition of genital aperture and size of the
belly.
Pectoral Fin: The pectoral fin of male has rough dorsal surface and the same is
longer than that of female. In female dorsal side of pectoral fin is smooth.
Genital Aperture: In female it is radish and swollen whereas in male the same is
not prominent. Further on applying gentle pressure, milt oozes out through the
genial aperture in male, but in female eggs ooze out.
Shape of the Belly: Belly of the female is soft swollen and bulging which is not
found is male.
Age and Size at First Sexual Maturity: Age and size at first sexual maturity of a given
species may vary depending on the temperature and other environmental factors.
Generally, all the 3 major carps attain sexual maturity in the second year and the males
mature earlier than female. The females grow faster than male and hence usually, the males
are smaller than female in a given population of the same age group. Hence carps of 2+
years and upto 5 years are preferred for breeding. After 5 years fecundity sets in and hence
is not advised to use for breeding.
Spawning Season: All the 3 major carps are seasonal riverine spawners, spawning during
the southwest monsoon months (June to August). They spawn in inundated shallow areas
adjacent to the river during floods. They do not breed usually in the first flood but breeding
during middle and later parts of monsoon. They do not spawn in confined waters.
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Fecundity: Fecundity in Catla has been reported to vary from 1.66 to 2.03 lacs per kg body
weight, in rohu it is reported to vary from 3.45 to 3.82 lacs per kg body weight and in
mrigal it is in range of 1.39 to 1.87 lacs per kg body wt. Thus out of 3 carps, rohu has
greater fecundity than the other two carps. The size of the water hardened eggs also varies
in three carps – largest size being in mrigal (20,000 Nos/ lit of water) and smallest being
that of rohu (30,000 Nos/lit of water). In catla 25000 eggs are usually found in one liter of
water hardened egg.
Breeding Biology of Shellfish
Reproductive Biology of Penaeid Shrimps and Prawns:
1.Age and Size :
Age at first breeding of tiger shrimp is not clearly established. It is reported that a
combination of age and body size along with feed availabe and favourable environmental
conditions influence the onset of sexual maturity. Nevertheless, the size is a matter for the
high fecundity and yield of good young ones.The males of body weight between 40 and 70g
and females with body weight of 60 to 80g are found sexually matured among wild stock,
whereas among farm reared shrimps, male weighing 35g and females weighing 40g are
found sexually matured. Other contributing factors might be resposnisble for differnce in
maturity.
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2.Sexual Demorphsm
Male Female
Presence of petasma in the 1st pleopod. Petasma is absent in the 1st pleopod in
female.
Presence of appendix masculina in the
2nd pleopod.
Appendix masculina is absent.
Thelycum is absent. Thelycum is present between pereopods IV
& V.
Gonopore is located at the base of
5th walking log.
Gonopore is located at the base of
3rd walking leg.
Smaller in size. Larger than male of the same age group
The male reproductive system
The male reproductive system consists of a pair of testes located in the cephalothorax (CT)
above the hepatopancreas (HP). The testes are translucent, composed of 6 lobes and all the
lobes are connected on the inner margin leading to vas deferens (vd). Vas deferens has 4
regions such as a proximal region, which is short and narrow, a medium portion which is
thick and larger, long narrow distal part and a muscular portion called terminal ampoule
which opens at the base of coxa of 5th perieopod. The gametes produced by the lobules of
testis are aggregated and stored in a bag and are called spermatophores, which are stored
in terminal ampoule. Spermatozoa of shrimps are small in size and lacks flagellum. Sperms
are immotile and attach to the egg at spike end.
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Fig: Macrobrachium sp. Reproductive system . A.Male. B.Female
The female reproductive system
There are a pair of ovaries which are partly fused extending almost the entire length of a
mature specimen. Each ovary consists of an anterior lobe, lateral lobes located dorsal to the
hepatopancreas and an abdominal lobe lying dorso-lateral to the intestine. The oviduct
originates from sixth lateral lobe, leading to the external genital papilla located at the base
of 3rd periopod.
Male reproductive organ-External Process
Male reproductive system externally consists of a pair of pleopods as accessory
reproductive organ, present on the inner side of the abdominal flap. The ejaculatory ducts
of the testes open into a small gential papilla at the base of the 3rd pair of the walking legs.
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The first pair of pleopod of the shrimp is made up of two segments, the basal one is broad,
rectangular and flattened and positioned close to the sternal wall and the terminal one is
long tube-like and tapering towards the tip. During mating with the female shrimp, this tip
is inserted into the seminal receptacle of the female.
The second pleopod helps in passing the spermatophores from the ejaculatory ducts into
the funnel-like portion of the first pleopod.The ejaculate from the gonad (testes) consists of
non-motile sperms and seminal plasma. Sperms are enclosed in numerous small
spermatophores and stored in the anterior vas deferens (vd), while the seminal plasma is
produced and stored in the posterior vas deferens.
Female reproductive organ - External
The female reproductive organ consists of a sperm receiving organ called Thelycum, which
is present in the middle portion of the last pair of the walking legs. There are two types of
Thelycum, namely closed thelycum and open thelycum based on the presence and absence
of the lateral plates in the thelycum, respectively.
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Maturity stages of ovary
In general the ovaries can be classified based on the maturity stages of the eggs. Broadly
the maturity stages are:
Immature: The ovaries in immatured female shrimps will be transparent / light yellowish
to ivory in colour; occupying 1/6th of body cavity; or like fili form. The Gonado
Somatic Index (GSI) at this stage will be strikingly low.
Maturing: Ovaries in maturing shrimps will be light to dark yellowish or orange in colour;
ovaries are filled with egg mass and therefore they will be occupying 1/3rd of body cavity.
Matured: Ovaries in matured females will be orange-red in colour; filled with matured
eggs with or without yolk granules. prominent seminal receptacle will be present;
occupying full body cavity and showing a high GSI. The females with matured ovary can be
identified by the presence of fully widened ovary in the body extending from cephalothorax
to the abdomen with prominent bulged portion in the ovary.
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Mating characteristics in open vs closed thelycum species
Penaeus species are grouped into two broad categories based on differences in morphology
of the female genital organ or thelycum which occupies the area from the third to the fifth
periopods. The “open thelycum” species include the members of
the Litopenaeus subgenera. They receive spermatophore or sperm packet from the male
and retain it externally for a few hours perior to spawning.
In contrast, the “closed thelycum” species are those which mate each time the female molts.
The closed thelycum female receives the spermatophore into her thelycum and then her
new exoskeleton gets hardened over it. She retains the spermatophore until she utilizes the
sperm in one or several spawning. The subgenera Penaeus, Fenneropenaues, Marsupenaeus
and Melicrotus have the closed or internal type thelycum.
This open thelycum females follow a sequence of molt-mature- mate and spawn while
closed thelycum species follow a sequence of molt- mate-mature and spawn. In both
groups, males with hard exoskeleton deposit spermatophores into females. Multiple
spawns may occur within one intermolt period for both open and closed thelycum speices.
The stimulus for courtship behaviour in Penaeus sp. is believed to be motivated by the sex
pheromone secreted in the females and received by the males through their antennules or
antennular flagella. In open thelycum species, mating occurs mainly in the evening and in
the night spawning will occur.
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Reproductive systems of male and female prawns
The male reproductive system of freshwater prawn consists of a pair of testes united at the
anterior end. It is located within the cephalothorax region of the male.
The female reproducitve system consists of a massive ovary situated in the cepahlothorax
region. The ovary can be clearly seen from the dorsal side of the body in the CT region as a
yellow coloured mass. The oviduct arising from the ovary opens outside in the base of the
3rd walking leg. The seminal receptacles are present in the exterior of the female genital
openings situated in the left and right sternites of sixth thoracic segment.
Externally four pairs of pleopods serve as accessory reproductive organs present on the
inner side of the second to fifth segments of the abdominal flap. Each pleopod consists of a
basal propodite from which arise the medial endopodite and lateral exopodite. The
exopodite bears a large number of pinnate setae. A cluster of long and very smooth setae
are on the endopodite, to which the extruded eggs are attached at the time of spawning .
Reproductive Biology of Crabs
1.Identification of sexes : Sexes can be morphologically distinguished based on the
shape of the abdominal flap. Though the shape of this flap is similar in both immature and
mature male, it is different in mature and immature female. In mature female the shape of
abdominal flap is half-round, while in immature female it is broad and triangular.
2.Sexual dimorphism : The sexes are separate and there is distinct sexual dimorphism
in crabs: Distinction between male & female based on morphological characters.
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Male Female
Abdominal flap which is folded firmly
against the ventral side is narrow (triangle
shape) of cephalothorax is slender and
triangular.
Appendages are present only on 1st and
2nd abdominal segments and the same are
modified to copulatory organs.
The claws are comparatively larger.
Abdominal flap folded against the ventral
side of body is broad (Round shape) and
berried females.
There are 4 pairs of abdominal
appendages present from 2nd to
5th segment and the same are used for
carrying the eggs.
The claws are smaller.
3.Size and maturity: The size range at first maturity in males and females of S.
tranquebarica and S. serrata is presented in the Table below:
Size range at first maturity in S. tranquebarica and S. serrata
Species Sex
Size range at first maturity
(Carapace width in mm)
S.tranquebarica
S.serrata
Male
Female
Male
Female
125-133
129-135
80-89
85-96
4.Mating: The size at first sexual maturity is 120 mm (carapace width) for larger species
(S.tranquebarica) and 83 mm (cw) for S. serrata. The early maturing ovary is bright orange
in colour where as, in matured – ready to spawn female, it is deep yellow in colour.
Copulation takes place between a hard shelled male and a freshly moulted, soft bodied
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female. The courtship is initiated by a “premating embrace” between hard shelled male and
hard shelled female which lasts for 2-3 days
5.Spawning: The ova are extruded by the female and the same are fertilized by the
sperm stored in the spematophores. The fertilized eggs are attached to the ovigerous setae
of the abdominal appendages. In S. tranquebarica, the nos. of eggs may be 2-3 million per
female of body weight whereas in S. serrata it is 0.5-2.5 million such as females with eggs
attached to the abdomen are called berried.
6.Incubation & hatching : The berried females carry their eggs for 2 weeks, during
which period the embryos develop. The eggs undergo change of colour from orange to grey
/ brown. Just before releasing the larvae, the eggs become grey black. After the incubation
period, the larvae hatch out. The hatched out larvae need feed for their growth.
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Reproductive Biology & Physiology of Lobsters:
Spiny lobsters are abundant in Gulf of Kutch, Maharastra,Gulf of Mannar and Andaman
Nicobar islands. It is a valuable fishery resource for the country as it brings in huge foreign
exchange and a much demanded sea food in the world. In recent years there has been a
decline in the catch due to over- exploitation of juveniles and spawning females. It is
necessary to protect this valuable resource by artificial seed production and ranching. This
has been emphasized by many natural and biological researchers in the world.
There are many bottle necks in the hatchery seed production of lobsters. However,
constantly efforts are being made to overcome the bottle necks and make the seed
production possible. Clear understanding of the basic reproductive biology and physiology
of lobsters is essential to make success in the seed production.
1.Sexual dimorphism
Sexes are separate in lobsters and usually males are larger than females. In the male, the
5th periopod or walking leg ends in single claws but in the female the tips of these legs are
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provided with three points formed by spurs used for carrying eggs attched to the under
side of the tail.
2.Identification of males and females
The males differ by the presence of swollen genital opening at the base of last pair of
periopod, whereas in the females it opens at the base of 3rd pair of periopod or walking
legs. The female lobsters have two branches of swimming legs whereas the male is having a
single branch. The animal has a prolonged breeding periopod and the peak season is
October- December under natural condition but it is observed that in confined conditions,
it breeds throughout the year in India.
3.Mating and spawning
Male lobster deposits spermatophores on the sternum of the female between the last three
pairs of appendages. The spermatophores turn black and are called as tar spots.
Development of eggs will take 24-72 hrs, during this periopod eggs will develop and
remain attached with pleopods of female lobster or oveigerous setae. The female carries
the eggs until the hatch out.
Conclusion:
Fish genetic breeding is a process that remolds heritable traits to obtain neotype and
improved varieties. For the purpose of genetic improvement, researchers can select for
desirable genetic traits, integrate a suite of traits from different donors, or alter the innate
genetic traits of a species. These improved varieties have, in many cases, facilitated the
development of the aquaculture industry by lowering costs and increasing both quality and
yield. The pertinent literatures and summarize the biological bases and application of
selection breeding technologies (containing traditional selective breeding, molecular
marker-assisted breeding, genome-wide selective breeding and breeding by controlling
single-sex groups), integration breeding technologies (containing cross breeding, nuclear
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transplantation, germline stem cells and germ cells transplantation, artificial gynogenesis,
artificial androgenesis and polyploid breeding) and modification breeding technologies
(represented by transgenic breeding) in fish genetic breeding.
References:
[ 1 ] http://ecoursesonline.iasri.res.in/course/view.php?id=585
[2]https://www.researchgate.net/publication/305329627_Methodologies_for_studying_fi
nfish_and_shellfish_biology
[ 3 ] https://en.wikipedia.org/wiki/Shellfish
[ 4 ] https://en.wikipedia.org/wiki/Fish_fin
[ 5 ] https://www.slideshare.net/KartikMondal1/finfish-breeding-and-hatchery-
management-61758258