controlling reproduction I

Question 1

What is the reason for controlling reproduction?

Answer 1

• expensive
• excessive
• intensive
• 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

Question 2

What are the major cues that trigger reproduction in temperate latitudes?

What is it in low latitudes?

Answer 2

Temperate latitudes: temperature, light

low latitudes: rainfall

Question 3

endogenous = ?

exogenous = outside

Answer 3

inside

Question 4

what is the major cue for most fish?

Answer 4

photoperiod

Question 5

How does Direction of photoperiod change:

Salmonids?

Atlantic cod?

Answer 5

Salmonids: decreasing daylength induces gonadogenesis
increasing daylength induces reproduction

Atlantic cod: increasing daylength induces gonadogenesis
decreasing daylength induces reproduction

Question 6

Reproductive maturation in fish can be advanced or delayed by altering daylength at
appropriate stages of the reproductive cycle

Answer 6

• *Long days** after summer solstice delays maturation
• *Long days** sooner after winter solstice and followed by shorter days advances maturation

Question 7

What is melatonin?

Answer 7

Melatonin produced in pineal gland produced under darkness
arylakylamine N-acetyltransferase (AANAT) acts on serotonin in biosynthetic pathway

Question 8

describe an experience to measure the content of melatonin

Answer 8

Question 9

what produces melatonin?

Answer 9

pineal gland

Question 10

what can either induce or prevent maturation depending on timing?

Answer 10

melatonin injections as well as pinealectomy

Question 11

other than melatonin what also regulates the circadian rhythm in fish?

Answer 11

clock genes

Question 12

what are the most important proteins in the body?

Answer 12

enzymes

Question 13

How does temperature affect ovulation in Atlantic salmon?

Answer 13

Question 14

why is oestrogen/estradiol (e.g. E2) produced and what for?

Answer 14

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