What is the reason for controlling reproduction?
-Temperate and warm water larvae often develop rapidly,
-production protocols are optimised to meet their changing requirements
-Many species are cannibalistic during larval/juvenile stages
-Hatcheries need to produce large amounts of larvae that are at the same developmental stage
-Depends on the time of spawning
What are the major cues that trigger reproduction in temperate latitudes?
What is it in low latitudes?
Temperate latitudes: temperature, light
low latitudes: rainfall
endogenous = ?
exogenous = outside
what is the major cue for most fish?
How does Direction of photoperiod change:
Salmonids: decreasing daylength induces gonadogenesis
increasing daylength induces reproduction
Atlantic cod: increasing daylength induces gonadogenesis
decreasing daylength induces reproduction
Reproductive maturation in fish can be advanced or delayed by altering daylength at
appropriate stages of the reproductive cycle
Long days after summer solstice delays maturation
Long days sooner after winter solstice and followed by shorter days advances maturation
What is melatonin?
Melatonin produced in pineal gland produced under darkness
arylakylamine N-acetyltransferase (AANAT) acts on serotonin in biosynthetic pathway
describe an experience to measure the content of melatonin
what produces melatonin?
what can either induce or prevent maturation depending on timing?
melatonin injections as well as pinealectomy
other than melatonin what also regulates the circadian rhythm in fish?
what are the most important proteins in the body?
How does temperature affect ovulation in Atlantic salmon?
why is oestrogen/estradiol (e.g. E2) produced and what for?
vitellogenesis (also known as yolk deposition) is the process of yolk formation via nutrients being deposited in the oocyte, or female germ cell involved in reproduction of lecithotrophic organisms