This document summarizes different reproductive strategies in fishes. It discusses that most fishes are oviparous and lay eggs externally. For marine fishes, the majority have pelagic eggs that float, while demersal eggs that sink are more common in freshwater. Some fishes are ovoviviparous or viviparous with internal fertilization. Different forms of parental care among fishes are also outlined, including by the male, female or both parents. Alternative reproductive strategies discussed include hermaphroditism, parthenogenesis, and natural polyploids and hybrids.
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.
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Fish usually migrate to feed or to reproduce, but in other cases the reasons are unclear.
Migrations involve the fish moving from one part of a water body to another on a regular basis. Some particular types of migration are anadromous, in which adult fish live in the sea and migrate into fresh water to spawn, and catadromous, in which adult fish live in fresh water and migrate into salt water to spawn.
Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at different times of year. The migratory movements may partly be linked to the fact that the fish cannot identify their own offspring and moving in this way prevents cannibalism. Some species have been described by the United Nations Convention on the Law of the Sea as highly migratory species. These are large pelagic fish that move in and out of the exclusive economic zones of different nations, and these are covered differently in the treaty from other fish.
Salmon and striped bass are well-known anadromous fish, and freshwater eels are catadromous fish that make large migrations. The bull shark is a euryhaline species that moves at will from fresh to salt water, and many marine fish make a diel vertical migration, rising to the surface to feed at night and sinking to lower layers of the ocean by day. Some fish such as tuna move to the north and south at different times of year following temperature gradients. The patterns of migration are of great interest to the fishing industry. Movements of fish in fresh water also occur; often the fish swim upriver to spawn, and these traditional movements are increasingly being disrupted by the building of dams.
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.
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Fish usually migrate to feed or to reproduce, but in other cases the reasons are unclear.
Migrations involve the fish moving from one part of a water body to another on a regular basis. Some particular types of migration are anadromous, in which adult fish live in the sea and migrate into fresh water to spawn, and catadromous, in which adult fish live in fresh water and migrate into salt water to spawn.
Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at different times of year. The migratory movements may partly be linked to the fact that the fish cannot identify their own offspring and moving in this way prevents cannibalism. Some species have been described by the United Nations Convention on the Law of the Sea as highly migratory species. These are large pelagic fish that move in and out of the exclusive economic zones of different nations, and these are covered differently in the treaty from other fish.
Salmon and striped bass are well-known anadromous fish, and freshwater eels are catadromous fish that make large migrations. The bull shark is a euryhaline species that moves at will from fresh to salt water, and many marine fish make a diel vertical migration, rising to the surface to feed at night and sinking to lower layers of the ocean by day. Some fish such as tuna move to the north and south at different times of year following temperature gradients. The patterns of migration are of great interest to the fishing industry. Movements of fish in fresh water also occur; often the fish swim upriver to spawn, and these traditional movements are increasingly being disrupted by the building of dams.
A fishing gear is the tool with which aquatic resources are captured, whereas the fishing method is how the gear is used. Gear also includes harvesting organisms.
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
In aquatic animals such as fish respiration takes place through special respiratory organs called gills, however lung fish respiration takes place through lungs. Gills are present on both the sides of the head of fish. The gills are covered by gill covers also called operculum. When the fish open its mouth, water is drawn into the buccal cavity and passed through the gills. The gills contain special type of cells that absorb the oxygen present in water. The absorbed oxygen is then supplied to all the cells of body through blood. In the cells, oxygen is converted into carbon dioxide and returned back to gills through blood. Ultimately, the gills release the carbon dioxide in water passing through them.
Respiration in Fish
The gills of fish are very efficient; it is estimated gills can extract about 80% oxygen dissolved in water. In addition to the respiratory organs, the gills have an important role in maintaining the right balance of salts in the body.
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.
Exotic fish introduction to india and their impact on indigenous speciesAshish sahu
The exotic varieties of fish have been found to encroach the natural water bodies and adversely affect the indigenous fish species. ... Owing to extensive practice of composite culture, three fast growing exotic fishes are introduced along with the three Indian major carps.
A fishing gear is the tool with which aquatic resources are captured, whereas the fishing method is how the gear is used. Gear also includes harvesting organisms.
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
In aquatic animals such as fish respiration takes place through special respiratory organs called gills, however lung fish respiration takes place through lungs. Gills are present on both the sides of the head of fish. The gills are covered by gill covers also called operculum. When the fish open its mouth, water is drawn into the buccal cavity and passed through the gills. The gills contain special type of cells that absorb the oxygen present in water. The absorbed oxygen is then supplied to all the cells of body through blood. In the cells, oxygen is converted into carbon dioxide and returned back to gills through blood. Ultimately, the gills release the carbon dioxide in water passing through them.
Respiration in Fish
The gills of fish are very efficient; it is estimated gills can extract about 80% oxygen dissolved in water. In addition to the respiratory organs, the gills have an important role in maintaining the right balance of salts in the body.
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.
Exotic fish introduction to india and their impact on indigenous speciesAshish sahu
The exotic varieties of fish have been found to encroach the natural water bodies and adversely affect the indigenous fish species. ... Owing to extensive practice of composite culture, three fast growing exotic fishes are introduced along with the three Indian major carps.
Amphibians are a class of animals like reptiles, mammals, and birds. They live the first part of their lives in the water and the last part on the land. When they hatch from their eggs, amphibians have gills so they can breathe in the water. They also have fins to help them swim, just like fish. Later, their bodies change, growing legs and lungs enabling them to live on the land. The word "amphibian" means two-lives, one in the water and one on land.
At Freshwater Aquarium Forum we share information about Freshwater Aquarium including setting up an aquarium, selecting filters and other equipment etc.
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.
PARENTAL CARE IN FISHES.pptx for 5th semborkhotudu123
Parental care in fishes varies greatly depending on the species. Some species exhibit no parental care at all, with the eggs being left to develop on their own, while others display elaborate forms of care, such as guarding the eggs, fanning them to provide oxygen, or even carrying the eggs in their mouths. These behaviors can enhance the survival of the offspring by protecting them from predators, providing oxygen, and ensuring optimal conditions for development.
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.
24. Parental care in fishes.........pptxsalehaasawer
Parental care can be defined as an association between the offspring and parents as to increase the chances of survival of offsprings. Parental care is not commonly seen in fishes, only the class cichlidae shows the parental care by brooding their offsprings.
Elasmobranchii is a subclass of Chondrichthyes or cartilaginous fish, including the sharks and the rays, skates, and sawfish. Members of this subclass are characterised by having four to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil.
placenta is established very early in development. In the placental Elasmohranchs, the Rays and Skates, the yolk-sac persists, the yolk being taken directly into the alimentary canal. In some cases an internal yolk-sac is also present. The blood vessels in the mesoblastic portion of the yolk-sac are also of use in absorbing the fiourishment contained. Observations on the Structure of Uterus & Placenta of Elasmobranchs 3 within it. External gill filaments present in the early stages of the ...
he second mode is that elasmobranchs give birth to live young. The picture is, however, somewhat more complicated than that because there are two methods of live birth. The first is aplacental viviparity (also referred to as ovoviviparity) and involves the pups being retained in the uterus, without a placental connection, until they are sufficiently developed to be able to fend for themselves.
Parental care in fishes, several fishes showing parental care,different types...Anand P P
parental care in fishes is very important role in survival of young ones.the important parental care methods included in this slide,and this slide also contain which are the fishes showing parental cares.
Fishing farming can be used to supply the depleting population of fish species around the globe. This presentation speak towards aquaculture and mariculture and issues with fish farming while speaking towards the benefits
Marine Birds Marine birds are those living in and making their living from the marine environment, which includes coastal areas, islands, estuaries, wetlands, and oceanic islands.
Consists of 328 species.
Sphenisciformes -Penguins
Procellariiformes -Albatrosses, petrels, storm-petrels, fulmars, shearwaters
Ciconiiformes - Herons, egrets, storks, ibis, spoonbills
Pelecaniformes - Pelicans, frigatebirds, gannets, boobies, cormorants, anhingas
Charadrii formes - Shorebirds, skuas, j
It is mainly a college presentation based on 'parental care in amphibia'. In this ppt, I discussed about parental care, basic facts of amphibia, the types and benefits of parental care taken by amphibia
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
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
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2. OVIPARITY: EGG LAYERS AND
EXTERNAL FERTILIZATION
• By far the vast majority of fishes are oviparous,
that is they produce eggs that are fertilized
after they have been laid
• About 96 percent of all living fishes are egg-
layers. Fishes exhibit a great variety of egg
types and adaptations. Morphologically and
physiologically they are tremendously
diverse
3. OVIPARITY IN MARINE
FISHES
• Very generally speaking eggs come in two kinds:
• 1. Pelagic eggs: eggs that float
• 2. Demersal eggs: eggs that sink
• By far the majority of marine fishes start out life as pelagic
eggs.
This includes:
• 1. Most all fishes that live over the continental slope
• 2. Nearly all those that range over surface waters of the
open ocean
• 3. All pelagic deep-sea fishes
4. • The eggs of these kinds of fishes are made buoyant by low-
density fluids acquired from the follicle cells of the ovary
or they develop an oil droplet independent of ovarian
tissue.
• The kinds of fishes that develop floating eggs must be able to
produce large numbers of small eggs. A fair-sized hake
(Merlucciusproductus) lays about 1 million eggs; fecundity
in cod (Gadusmorhua)ranges from 2–9 million eggs;
5.
6. • High numbers of eggs are necessary for successful
recruitment because thousands of eggs and larvae
are dispersed into areas far beyond the optimal
conditions for survival, and thousands die long
before hatching or metamorphosis to juvenile
stages
7. Demersaleggs
• Some marine fishes lay demersale eggs, that is, eggs
that are heavier than water and thus sink to the
bottom after being laid, or they are laid directly on
the bottom, or placed in nests, or fastened to
rocks, shells, seaweed, sponges, and a whole host
of other objects
8. OVIPARITY IN FRESHWATER
FISHES
• While most marine species lay pelagic eggs, demersal or
non-floating eggs are the rule in freshwater—they sink to
the bottom. There are several reasons for this:
• 1.It is physiologically more difficult to produce an egg with
a specific gravity less than freshwater.
• 2. Freshwater does not provide the rich food resource in its
upper layers as does the marine environment.
• 3. Fast moving rivers and streams would remove nearly all
eggs and larvae from a local population preventing
recruitment
9. OVOVIVIPARITY AND VIVIPARITY: INTERNAL
FERTILIZATION
• Ovoviviparous and viviparous fishes are similar in that both
are live-bearing forms that require internal fertilization.
However, they differ fundamentally with regard to the
source of nutrition for the developing young.
• In ovoviviparous forms the eggs are retained and fertilized
within the body, but the young receive no nutrients from the
mother—they must rely solely on what is provided in the
yolk. In viviparous forms, the young are nourished by some
kind of placental connection with the mother.
10. Ovoviviparity and viviparity are relatively rare among fishes—they
include only about 4 percent of all living fishes, but they are among the
most interesting when it comes to reproduction.
. Representatives are found among the following taxa: Chondrichthyes
(sharks and their allies), live-bearers(i.e., guppies and their allies,
family Poeciliidae and the coelacanths(genus Latimeria).
. Internal fertilization involves the use of some kind of organ, a
structure used to pass sperm to the female. Most live-bearing fishes
have males with such an organ. They are usually modified analog
pelvic fins.
11.
12. The guppy (genus Poecilia) is the best known case of
ovoviviparity in fishes—the eggs are fertilized within the egg
follicles of the ovary where they develop for some time.
• Some marine forms and many more freshwater forms retain their
eggs after they are laid, that is, they practice parental care.
Parental care takes on a host of different modes, from simple to
highly complex
PARENTAL CARE
13. Forms of parental care:
A.Male parental care: sea catfishes (Ariidae), sticklebacks (Gasterosteidae),
pipe fishes (Syngnathidae), and greenlings (Hexagrammidae)
B. Female parental care:
1.Oviparity with post-spawning care: the cichlidaegenus Oreochromis
2. Ovoviviparity without post-spawning care: rockfishes, genus Sebastes
3. Viviparity without post-spawning care: Elasmobranches, livebearers (e.g.,
Genus Poecilia), surfperches (Embiotocidae)
C.Biparental care: bullheads (Ictaluridae), several cichlid genera
(e.g.,Cichlasomaand Symphysodon)
D. Juvenile helpers: some African cichlids (e.g., genus Lamprologus)
14. Reproductive strategies
several males to each female (Salmoniformes, lampreys)
several females to each male (Gobiidae)
single-pair matings (guppies)
24. Reproductive strategies
bearers
- internal bearers (viviparity)
facultative - killifishes
obligate - Lake Baikal sculpins,
marine rockfishes (Scorpaenidae)
livebearers - Poeciliids, many sharks
gradient of nutrient supply from mother
superfetation
placental viviparity - sharks
25.
26. Alternative reproductive strategies
Hermaphrodites
synchronous (or simultaneous) hermaphrodites
Myctophiformes: (laternfishes) - several families
Atheriniformes: Aplocheilidae, Poeciliidae
Perciformes: Serranidae (sea basses, hamlets),
Labridae (wrasses), and others
"Egg-trading" in black hamlets Hypoplectrus nigricans (serranid)
27. Alternative reproductive strategies
Hermaphroditism
consecutive (sequential) hermaphrodites
first male (protandrous) – less common
Stomiiformes (lightfish, dragonfish)
Scorpaeniformes: Platycephalidae
Perciformes: Serranidae, Labridae, and others
blue-headed wrasse
29. Alternative reproductive strategies
parthenogenesis:
females produce diploid eggs, no sperm used
premeiotic endomitosis - mitotic division without cytokinesis
gynogenesis:
females produce diploid eggs, use sperm to stimulate development
male genome not used
congeneric species are used for sperm
hybridogenesis: one genome from female in egg,
male genome discarded - then uses sperm to restore ploidy
- no crossing over
example: Poeciliopsis monacha-lucida
30. Natural polyploids
triploids - Cyprinidontiformes: Poeciliid triploids
tetraploids (autotetraploids vs. allotetraploids)
hexaploids and octaploids (rare in carp)