1. Fish bodies are divided into head, trunk, and tail sections, though divisions may not always be visible externally. They are classified based on body parts, mouth location and size, tail shape, color, and adaptations.
2. Body shape indicates how a fish moves and lives, with categories including fusiform for fast swimmers, depressiform for bottom dwellers, and anguilliform for eel-like fish.
3. Fish have a variety of fin, scale, mouth, coloration, and reproductive adaptations that help with functions like swimming, defense from predators, and reproduction.
A short description about magur fish.The walking catfish (Clarias batrachus) is a species of freshwater airbreathing catfish native to Southeast Asia, but also introduced outside its native range where it is considered an invasive species. It is named for its ability to "walk" across dry land, to find food or suitable environments. While it does not truly walk as most bipeds or quadrupeds do, it has the ability to use its pectoral fins to keep it upright as it makes a wiggling motion with snakelike movements.[2] This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams and rivers, flooded rice paddies or temporary pools which may dry up
it is about the length and weight relationship of fish , growth, length, weight, absolute growth, isometric growth, relative growth, allometric growth,
A short description about magur fish.The walking catfish (Clarias batrachus) is a species of freshwater airbreathing catfish native to Southeast Asia, but also introduced outside its native range where it is considered an invasive species. It is named for its ability to "walk" across dry land, to find food or suitable environments. While it does not truly walk as most bipeds or quadrupeds do, it has the ability to use its pectoral fins to keep it upright as it makes a wiggling motion with snakelike movements.[2] This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams and rivers, flooded rice paddies or temporary pools which may dry up
it is about the length and weight relationship of fish , growth, length, weight, absolute growth, isometric growth, relative growth, allometric growth,
Many farmers have been unable to successfully breed African Catfish.Several attempts made have given unfruitful results. In this guide, Lanre Ogunsina lists his own simple 19 proven steps to efficiently breed the African Catfish.
Due to the difficulties of getting consistent, fast growing, disease resistant and uniform sized catfish fingerlings and juveniles, the African Catfish Hatchery came into existence.
In the African Catfish Hatchery, catfish fry âcome outâ from eggs under an artificial condition in commercial numbers. These fry grow into fingerlings and they later become juveniles.
In the International Year of the Coral Reef (2008), you have the opportunity to help celebrate and record Fijiâs amazing coral reef biodiversity, show you care about our worldâs delicate coral reef systems, and have fun, by taking part in a week-long hunt for the Great Fiji Butterflyfish!
Easy to do, this is suitable for visitors and locals alike, whether you are a snorkeler, SCUBA diver or Glass-bottom boat passenger. We hope that tourists, school children, scientists and all people with an interest in the marine environment will take to the reefs with us to search for Butterflyfish.
Double Saddled Butterflyfish, FijiThe Great Fiji Butterflyfish Count will be held around Fiji from the 2nd to the 8th November 2008. You can do a single count during that week, or take place as many times as you like during that week, so that you cover different reefs. All data will be gratefully accepted!
So, grab your Great Fiji Butterflyfish Count slate from participating resorts and dive operators, put on your snorkel and mask and dive into the beautiful blue waters of Fiji, to be a part of history!
Fish is the major economically exported source. There are various products are there based on fish. The major products are exported to other countries than utilizing in India such as oyster which are more preferred for eaten by Germans and Italians.
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.
Many farmers have been unable to successfully breed African Catfish.Several attempts made have given unfruitful results. In this guide, Lanre Ogunsina lists his own simple 19 proven steps to efficiently breed the African Catfish.
Due to the difficulties of getting consistent, fast growing, disease resistant and uniform sized catfish fingerlings and juveniles, the African Catfish Hatchery came into existence.
In the African Catfish Hatchery, catfish fry âcome outâ from eggs under an artificial condition in commercial numbers. These fry grow into fingerlings and they later become juveniles.
In the International Year of the Coral Reef (2008), you have the opportunity to help celebrate and record Fijiâs amazing coral reef biodiversity, show you care about our worldâs delicate coral reef systems, and have fun, by taking part in a week-long hunt for the Great Fiji Butterflyfish!
Easy to do, this is suitable for visitors and locals alike, whether you are a snorkeler, SCUBA diver or Glass-bottom boat passenger. We hope that tourists, school children, scientists and all people with an interest in the marine environment will take to the reefs with us to search for Butterflyfish.
Double Saddled Butterflyfish, FijiThe Great Fiji Butterflyfish Count will be held around Fiji from the 2nd to the 8th November 2008. You can do a single count during that week, or take place as many times as you like during that week, so that you cover different reefs. All data will be gratefully accepted!
So, grab your Great Fiji Butterflyfish Count slate from participating resorts and dive operators, put on your snorkel and mask and dive into the beautiful blue waters of Fiji, to be a part of history!
Fish is the major economically exported source. There are various products are there based on fish. The major products are exported to other countries than utilizing in India such as oyster which are more preferred for eaten by Germans and Italians.
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.
Fish are the gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups.
Training manual on species identification 2017 vivekanand bharti_basic finfis...Ashish sahu
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The ID tools reviewed are: Use of scientific experts (taxonomists) and folk local experts, taxonomic reference collections, image recognition systems, field guides based on dichotomous keys; interactive electronic keys (e.g. IPOFIS), morphometrics (e.g. IPez), scale and otolith morphology, genetic methods
Oarfish are large, greatly elongated, pelagic lampriform fish belonging to the small family Regalecidae. Found in all temperate to tropical oceans yet rarely seen, the oarfish family contains three species in two genera. One of these, the giant oarfish, is the longest bony fish alive, growing up to 8 m in length. Wikipedia
Class: Actinopterygii
Scientific name: Regalecidae
Phylum: Chordata
Higher classification: Lampriformes
Rank: Family
Kingdom: Animalia
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
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Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The systemâs unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Observation of Ioâs Resurfacing via Plume Deposition Using Ground-based Adapt...SĂŠrgio Sacani
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Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Ioâs 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 Ioâs 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 Ioâs surface using adaptive
optics at visible wavelengths.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.SĂŠrgio Sacani
Â
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.
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 âsmallâ 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 .
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
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Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other  chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released. Â
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules -Â a chemical called pyruvate. A small amount of ATP is formed during this process.Â
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to âburnâ the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP.  Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.Â
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.Â
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 â 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : Â cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
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Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.Â
 Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
Â
As consumer awareness of health and wellness rises, the nutraceutical marketâwhich includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutritionâis 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.
3. Body Divisions
0Their body is divided
into:
- head
- trunk
- and tail
0although the divisions
are not always
externally visible.
4. The caudal peduncle
0 is the narrow part of the fish's body to which the
caudal or tail fin is attached. The hypural joint is the
joint between the caudal fin and the last of the
vertebrae. The hypural is often fan-shaped.
5.
6.
7.
8. Fishes were described and
classified by
1. Body parts
2. Mouth location and size
3. Tail shape
4. Color
5. Some special adaptations
9. Body shape
0A good indicator of how a fish moves and
where it lives.
1. flat or depressiform
ďźThey normally live on the bottom of the sea floor
ďźflap their fins up and down to swim through the
water in the same way a bird flaps its wings.
ďźex. Skates and flounder
11. Body shape
2. Long and Skinny or Filiform
ďź slither through the water like a snake
ďź examples - like an eel
Snake eel
American eel
12. Body Shape
3. oval or fusiform
ďźsection like a salmon or bass are fast swimmers
ďźusually live in open water
Largemouth Bass
13. Body Shape
Compressiform
ďźshape like that of angelfish looks thin when viewed
from the front.
ďźThis body shape is well designed for making quick
turns and quick bursts of speed over short distances.
ďźCompressiform fish commonly live
where there are many places to
take refuge such as ponds, lakes,
or coral reefs, or
ďźThey school together in shallow
open waters.
Blue Gill
Black Crappie
14. Body Shape
6. Sagittiform
ďźThese body shapes are good for rover predators,
which depend on an ability to strike quickly--often
from a hiding place.
ďź"Arrow-like." Other fish with this body type include
pikes, gars, topminnows, killifish, needlefish, and
barracuda.
16. 7. Taeniform
ďź"Ribbon-like." Example shown is a gunnel.
This shape is good for hiding in cracks and
crevices, but fishes like this do not move very
fast.
17. 8. Globiform
ďź"Globe-like." Shown is a smooth lumpsucker.
This, too, would be an unusual shape in a
freshwater environment, although pupfish
come close.
18. 9. Anguilliform
ďź"Eel-like." Many eels, of course have this
shape. Shown is a brook lamprey. This shape
allows a fish to enter and hide in very narrow
openings, and also helps the fish resist the
force of current.
19.
20. Another way to classify body types is
by their function. In this system:
1. Rover predators (fish that more or less constantly
swim about searching for prey) include fusiform body
types, as well as salmon, trout, and bass; they have
pointed heads, terminal mouths, narrowed caudal
peduncles, and forked tails.
Salmon
21. 2. Lie-in-wait predators (predators that catch their
prey by ambush) include sagittiform body types; they
have dorsal and anal fins placed well back on the body, a
streamlined form, flattened heads, and large, well-
toothed mouths.
22. 3. Surface-oriented fishes are often small, with
mouths that are directed upwards toward the surface of
the water. These fishes often swim just below the
surface, and eat food that is floating on the surface or
flying above it. Topminnows, killifish, freshwater
hatchetfish, halfbeaks, and flying fish are examples of
surface-oriented fishes.
https://www.youtube.com/watch?v=4T1SQtavaUM
23. 4. Deep-bodied fish include all the compressiform
types, and are found widely in places where the ability
to make tight, close turns is of value, such as rock reefs,
coral reefs, thickly vegetated areas, and schools.
24. 5. Eel-like fish include taeniform, anguilliform, and
filiform shapes all in one category.
6. Bottom fish is a very broad category that includes
bottom rovers like catfishes, suckers, and sturgeons,
bottom clingers like sculpins, bottom hiders like
darters and blennies, and depressiform body types,
like flatfish.
26. Pectoral fins:
ďPectoral fins may be horizontal and down low, like in a
salmon, trout, shark, or sturgeon, and used mainly for
gliding.
ďThese are often are used for swimming, holding
position, and changing directions quickly.
27. Pelvic fin location:
ďPelvic fins are usual abdominal, meaning that they are
attached midway down the belly.
ďWhen the pelvic fins are below the pectoral fins, such
as can be seen in the diagram of the non-existent fish
above, they are termed thoracic.
ďWhen a thoracic pelvic fin is attached under the gills,
it may also be called jugular, and if under the chin or
eye, mental.
28. Caudal fin shape:
A. The homocercal (homo-SUR-kul) tail is a modern
development. It is symmetrical.
ďIt includes truncate, square, slightly forked, and deeply
forked types. It is by far the most common caudal fin
shape, shared by most fishes.
29. B. The heterocercal tail
ďis an ancient form,
ď possessed by only a few primitive fishes, such as
sharks, sturgeon, and paddlefish.
ďIt was a necessary tail shape when fishes had no swim
bladders and were heavy in the front; if the fish tried
to use a symmetrical tail, it would have plunged
toward the bottom. Instead, it developed a tail with a
deliberately downward-driving design and
supplemented it with horizontal, plane-like pectoral
fins that transformed that downward force into a
horizontal, forward-driving force.
30. C. This tail has a non-differentiated caudal
fin. This may be found on eels of all sorts,
as well as lampreys.
31. Fish Tail indicates how the fish moves and lives as well.
Types of fish tails:
1. truncated tail
ďgood for maneuverability and short bursts of speed
ďnot as much drag as the round shape
ďExamples: killifish
ďThis kind of tail is commonly found on fish in coastal
embayments.
33. 2. Forked Tail
ďis good for maneuverability and speed over longer
distances.
ďLess drag Forked tail
34. 3. Round Tail
ďLarge amounts of surface area
for effective maneuvering and
acceleration
ďbut creates drag causing the
fish to tire easily
Round tail
Clown fish
36. 5. Lunate or crescent
ďshaped tails like those found on a swordfish
ďnot good for maneuvering
ďallow for great speed over long distances
ďusually found on fish that live in the open ocean.
39. Morphology: Scale type
ďScales have evolved over time and are of major
importance in classifying fishes. Most scales are
deeply buried in the fish's epidermis, or outer skin
layer, with only part of them showing. Below the
pictures of scales are examples of how the scales
would look on the fish's body.
40. Ganoid
ď"primitive" kind of scale
ďreminder of the time
when fishes used armor
plating to protect
themselves
ďGanoid scales are hard
and smooth, and may take
the form of only a few
scales
41. Placoid
ďSharks have placoid (PLAK-
oyd) scales: tiny, tooth-like
structures that are partially
embedded in the skin.
ďThese tiny, pointed scales,
made of the same materials
as their (and our) teeth,
make their skin feel like
sandpaper.
42. Cycloid
ďMany fishes with which we
are most familiar have cycloid
scales, which are the thin,
round, almost transparent
scales that we find when we
are cleaning trout, salmon, or
herring.
ďThese scales are mostly
buried in the epidermis,
allowing only the small
posterior margin to show.
43. Ctenoid
ďwhich are much like cycloid scales
except that they have tiny, comb-
like projections (ctenii) on their
posterior edges (the edges that
show, and are not buried in skin).
ďThe colors of brightly colored
fishes also show on these
posterior edges.
44. ďBesides the scale types, there
are also cosmoid scales, as well
as scaleless fishes (sculpins,
many catfish, some eels, and
swordfish), and fishes which
have scales so deeply buried
that they look scaleless (many
tunas and anguillid eels).
51. 2. Countershading-dorsally darkened and ventrally
whitened, dark helps fish to blend in with the dark
bottom when viewed from above whereas the white
belly helps them to blend with the sky or clearer
waters above when viewed from below
52. 3. Disruptive Coloration -another form of
camouflage, colors and patterns (i.e.. presence of
color stripes or bars) that break up the outline of a
fish making it harder to see
Basslet
firefish
53. 4. Eye Spot (false eye)-black spot located near base of
the tail used to confuse predators
Four Eye Butterfly Fish.
54. 5. Thickened Scales -protective covering making
their hard carpace relatively immune to predation
56. 7. Schooling-fish swimming
in schools may have a
greater chance to survive
than if by themselves
because an individual fish
in a school may be harder
to pick out by a predator
58. Parthenogenesis
o There are two known species that undergo
parthenogenesis as their chosen form of reproduction.
o The Amazon Molly Poecilia formosa of Mexico and Texas
o Texas Silverside Menidia clarkhubbsi
59. Sexual Reproduction
o The standard form of reproduction is through the
union of male and female gametes
o Sexual maturity is reached at different ages for
different species. Factors that influence sexual
maturity include age, gender and size.
o Many bony fishes become sexually mature between
one and five years. Sturgeon take up to 15 years to
mature.
o In general, species of a small maximum size begin
reproducing at a younger age than those that have a
large maximum size.
60. Diversity in Gender
o The vast majority of fish are âdioeciousâ meaning that
there are male and female genders in separate bodies
o âHermaphrodismâ, is the alternative to dioecism
o Species can be either hermaphroditic simultaneously or
sequentially
o If simultaneous then they are both genders at the same
time
o If sequentially then the species changes genders due to
environmental cues
o Species that are born male are called protandrous
o Species that are born female are called Protogynous
61. Modes of Sexual
Reproduction
o There are three primary ways that fish reproduce
o Ovopartity â lay undeveloped eggs, external fertilization
(90% of bony fish), internal fertilization (some sharks
and rays)
o Ovovivparity â internal development â without direct
maternal nourishment â advanced at birth (most sharks
& rays) â Larval birth (some scorpeaniforme â rockfish)
o Viviparity â Internal development â direct nourishment
from mother â fully advanced at birth (some sharks, surf
perches)
62. Sexual Dimorphism
o In most species of fish the females are larger than the
males, this sexual dimorphism is not normally more
than a difference of about 10-15% by length.
o There are a family of fish however, that the male is
significantly smaller and lives as a parasite on the
female getting all of his nutrients from her.
63. Young Protection
o There are many different forms that fish use to protect
the young/eggs
o Mouth brooding, one adult collects the eggs in their
mouth after fertilization and keeps them safe until they
hatch (cichlids)
o External brooding pouch, or with the eggs stuck to the
males body (seahorses)
o Gill brooding, eggs are kept in the gill cavity of the adult