Clarias batrachus, commonly known as the walking catfish or Thai catfish, is a species of air-breathing catfish. Here's some information about the reproduction, breeding techniques, hormonal usage, and related aspects of Clarias batrachus:
1. Sexual Dimorphism: Male and female walking catfish can be distinguished based on certain physical characteristics. Males tend to have a larger size, broader head, and more prominent spines on their pectoral fins compared to females.
2. Breeding Conditions: Walking catfish are known to breed during the rainy season or when there is an increase in water levels. They typically prefer warm water temperatures.
3. Spawning Behavior: Walking catfish are nest builders, and males exhibit paternal care. The male constructs a nest by digging a depression in the substrate, often in muddy areas or among aquatic vegetation.
4. Hormonal Induction: In aquaculture settings, hormonal induction is commonly used to synchronize and stimulate breeding in walking catfish. Hormones like human chorionic gonadotropin (hCG), luteinizing hormone-releasing hormone analogs (LHRHa), or synthetic hormone analogs are used to induce ovulation in females and spermiation in males. The dosage and timing of hormone administration depend on factors such as fish size, maturity, water temperature, and breeding objectives.
5. Breeding Tank Setup: Prepare suitable breeding tanks or ponds for walking catfish reproduction. The tanks should have appropriate water conditions, including a temperature range of 25-30°C (77-86°F), pH around 7, and good aeration to ensure oxygen supply.
6. Hormone Injection: Hormonal injection is typically performed on female walking catfish to induce ovulation. The hormone is administered through intramuscular or subcutaneous injections. It is important to handle the fish carefully during the injection process to minimize stress and ensure proper dosage delivery.
7. Spawning Technique: After hormone injection, the female walking catfish is introduced into the male's nest. The male initiates courtship behavior by circling, nudging, and wrapping his body around the female. This stimulates the release of eggs by the female and sperm by the male for fertilization.
8. Nest Construction and Preparation: Male walking catfish construct nests by excavating depressions in the substrate. They may create tunnels leading to the nest for protection. Nests are usually built in shallow waters, often in muddy areas or among aquatic vegetation.
9. Egg Collection and Incubation: Once the eggs are fertilized, they adhere to the nest walls. The male walking catfish guards the nest and ensures adequate oxygenation of the eggs by fanning them with his pectoral fins. During incubation, maintain suitable water conditions and temperature for the eggs to develop.
Larval Rearing: After hatching, the walking catfish larvae have external gills and can breathe atmospheric air. Provide appropriate rearing conditions, including water quality, temperature.
The pomfrets constitute about 2.32% of the total marine fish production in India. The bulk of the catch comes from Maharashtra and Gujarat States, which jointly contribute to about 61% of the total all India pomfret landings.
Among the demersal fishes, pomfrets belonging to the family Stromateidae are found in the catches all long the coast of India, particularly in Maharashtra and Gujarat States.
This presentation gives a quick account of the activities of the Fisheries department in inland fisheries and aquaculture in Tamil Nadu. It also talks about the development of fish culture in community ponds& tanks and the need for reforms in community tank management.
Clarias batrachus, commonly known as the walking catfish or Thai catfish, is a species of air-breathing catfish. Here's some information about the reproduction, breeding techniques, hormonal usage, and related aspects of Clarias batrachus:
1. Sexual Dimorphism: Male and female walking catfish can be distinguished based on certain physical characteristics. Males tend to have a larger size, broader head, and more prominent spines on their pectoral fins compared to females.
2. Breeding Conditions: Walking catfish are known to breed during the rainy season or when there is an increase in water levels. They typically prefer warm water temperatures.
3. Spawning Behavior: Walking catfish are nest builders, and males exhibit paternal care. The male constructs a nest by digging a depression in the substrate, often in muddy areas or among aquatic vegetation.
4. Hormonal Induction: In aquaculture settings, hormonal induction is commonly used to synchronize and stimulate breeding in walking catfish. Hormones like human chorionic gonadotropin (hCG), luteinizing hormone-releasing hormone analogs (LHRHa), or synthetic hormone analogs are used to induce ovulation in females and spermiation in males. The dosage and timing of hormone administration depend on factors such as fish size, maturity, water temperature, and breeding objectives.
5. Breeding Tank Setup: Prepare suitable breeding tanks or ponds for walking catfish reproduction. The tanks should have appropriate water conditions, including a temperature range of 25-30°C (77-86°F), pH around 7, and good aeration to ensure oxygen supply.
6. Hormone Injection: Hormonal injection is typically performed on female walking catfish to induce ovulation. The hormone is administered through intramuscular or subcutaneous injections. It is important to handle the fish carefully during the injection process to minimize stress and ensure proper dosage delivery.
7. Spawning Technique: After hormone injection, the female walking catfish is introduced into the male's nest. The male initiates courtship behavior by circling, nudging, and wrapping his body around the female. This stimulates the release of eggs by the female and sperm by the male for fertilization.
8. Nest Construction and Preparation: Male walking catfish construct nests by excavating depressions in the substrate. They may create tunnels leading to the nest for protection. Nests are usually built in shallow waters, often in muddy areas or among aquatic vegetation.
9. Egg Collection and Incubation: Once the eggs are fertilized, they adhere to the nest walls. The male walking catfish guards the nest and ensures adequate oxygenation of the eggs by fanning them with his pectoral fins. During incubation, maintain suitable water conditions and temperature for the eggs to develop.
Larval Rearing: After hatching, the walking catfish larvae have external gills and can breathe atmospheric air. Provide appropriate rearing conditions, including water quality, temperature.
The pomfrets constitute about 2.32% of the total marine fish production in India. The bulk of the catch comes from Maharashtra and Gujarat States, which jointly contribute to about 61% of the total all India pomfret landings.
Among the demersal fishes, pomfrets belonging to the family Stromateidae are found in the catches all long the coast of India, particularly in Maharashtra and Gujarat States.
This presentation gives a quick account of the activities of the Fisheries department in inland fisheries and aquaculture in Tamil Nadu. It also talks about the development of fish culture in community ponds& tanks and the need for reforms in community tank management.
1. Modul Klar for havet
Velkommen til Newton Gildeskål
KLAR FOR HAVET
2. Modulen omhandler
• Hvordan finner man ut om laksen er klar for å leve i havet?
• Læringsmål,
• Elevene skal kunne…
• …forklare hva osmose, diffusjon og osmoseregulering er og hva
sammenhengen mellom disse prosessene og fiskens tilpassninger til et liv
i fersk-og saltvann er.
• … beskrive laksens livssyklus.
• …utføre noen matematiske beregninger
• …vurdere på bakgrunn av innsamlete data, om fisken er sjøvannstolerant
Modul Klar for havet
3. Modul Klar for havet
Innholdsfortegnelse
• Laksens livssyklus
• Laksens tilpasninger til et liv i fersk- og saltvann
• Laks i oppdrettsanlegg
• Hva er en smolt?
• Er laksen klar for å settes i havet ? Hvordan finner vi dette ut?
• Sjøvannstest
• Hvordan vurderer vi laksens utseende?
• Hvordan tapper vi blod fra laksen?
• Hvordan måler vi laksens kloridkonsentrasjon i blodet (plasma)?
• Hva gjør vi med datamengden vi har samlet inn og hvordan kan
statistikk være et nyttig verktøy i denne sammenhengen?
4. Modul Klar for havet
Problemstillinger som behandles i dag:
• Hvilken muligheter finnes det i oppdrettsanlegg for
å teste om fiskene tolererer sjøvann allerede?
• Hvordan kan mennesker påvirke laksen sin
fysiologi i oppdrettsanlegg?
6. FERSKVANN
Fisk er mer salt enn
omgivelsene og vann
diffunderer inn
gjennom
halvgjennomtrengelig
membran
SJØVANN
Fisk er mindre salt
enn omgivelsene
og vann diffunderer ut
gjennom
halvgjennomtrengelig
membran
Repetisjon - Osmoregulering
Modul Klar for havet
7. Modul Klar for havet
Hvordan fungerer fiskeoppdrett ? Eksempel fra Smolten AS:
• http://www.youtube.com/watch?v=xD0GjX7IsB8
9. Laksens livsstadier i saltvann
Sentrale begreper i
oppdrettsanlegg
• Postsmolt
• Slaktefisk
• Fisk som går i avl:
• Stamfisk
Kjønnsmoden hann laks
Modul Klar for havet
10. Modul Klar for havet
Smoltifisering
• Anadrome fisker venner seg til et liv i saltvann og
lærer å skille ut salter.
• Smoltifiseringsprosessen er avhengig av art,
vanntemperatur, dagslengde, fôrtilgang og
vekstevne
• Prosessen tas 1-4 år i naturen og kan manipuleres i
oppdrett slik at det tar kortere tid.
• I oppdrett må mennesker finne ut om de unge
fiskene er klare til å settes ut i merdene i sjøen.
11. Modul Klar for havet
SMOLTKVALITET
Det viktigste kvalitetskravet til smolten er at den har utviklet:
sjøvannstoleranse
dvs. være i stand til å leve i sjøvann
• Endringene som
skjer gjennom
smoltifiseringen
brukes til å vurdere
SMOLTKVALITET
12. Fisken eksponeres saltvann i 48 timer.
Modul Klar for havet
SJØVANNSTEST
• Fisken utsettes for en standardisert saltbelastning for å teste om fisken har
allerede utviklet evnen til å skille ut salter
kloridkonsentrajon i plasma måles
35 ‰ saltvann
13. SMOLTKVALITET –
Elevenes datainnsammling
Modul Klar for havet
2. Beregne kondisjonsfaktor
1. Vurdere fiskens utseende:
a) Vurdere sølvfargeindeks
b) Lengdemål og veie overlevende fisk etter sjøvannstesten til nærmeste cm
og gram
3. Ta blodprøver.
Den utleverte fisken har gjennomgått sjøvannstesten før!
5. Noter innsamlete data på utlevert skjema og gjør noen
beregninger.
4. Måle plasmakloridkonsentrasjon.
15. Sølvfargeindeks vurderes og noteres ned i skjemaet
Parr Smolt
1. Vurdere fiskens utseende
Modul Klar for havet
16. Modul Klar for havet
Parr - utseende
fargen går i ett med
omgivelsene
Parrmerker dypt i huden
Kort og litt butt fisk som
har høy kondisjonsfaktor
→ Parr er snart klar for havet
17. Modul Klar for havet
Smolt - utseende
smoltifiseringsprosess:
Parmerkene dekket over
lysreflekterende krystaller
Sidene blir blanke, ryggen
mørk, buken blir kvit
Finnene endrer form/farge
slank og sølvfarget smolt
Vi kaller tidspunktet når fisken er klar for havet for “Smoltvinduet”
økt vekst i haleregionen
sølvfargeindeks: 4, helt blank
18. 3. Ta blodprøve
• Blod tappes fra rygg
venen med en 1 ml
sprøyte som er tilsatt
en ørliten mengde
heparin
• Blod overføres til
Eppendorf-rør som
settes på is
Modul Klar for havet
19. 4. Plasmakloridkonsentrasjon - Sentrifugering
Med en Mikrosentrifuge
sentrifugeres blodcellene
ned (6000 rpm, 8 min)
Plasma (øverst) pipetteres av
og overføres til nye
Eppendorf-rør
Modul Klar for havet
Blotprøve før sentrifugering
Sentrifuge
Pipettering av plasma
20. 4. Plasmakloridkonsentrasjon - Titrering
KLORIDTITRATOR
Blodplasma
analyseres for
innhold av klorid
Modul Klar for havet
21. Modul Klar for havet
5. Beregninger
• Når alle dataene er
utfylt i skjemaet
beregnes
gjennomsnittsverdier
• Median beregnes for
sølvfargeindeks
23. Ion Normalverdi fisk i
Ferskvann
Normalverdi fisk i
Sjøvann
Klorid (mM/l) 115-135 130-150
Modul Klar for havet
• Når lakseyngelen har oppnådd sjøvannstoleranse, vil
innholdet av klorid i plasma etter sjøvannstest ligge
rundt 130-150 mM/l
• Kondisjonsfaktoren < 1,1
• Sølvfargeindeksen: 4
Resultater
24. Konklusjon
På bakgrunn av de
innsamlete dataene gis en
vurdering om
lakseyngelen har utviklet
sjøvannstoleranse, slik at
fisken kan overføres til
videre produksjon i havet.
Modul Klar for havet
Dersom våre verdier avviker, tyder dette på
at fisken ikke er klar for havet.
