Reproduction Fisheries Flashcards
Considerations when analyzing reproduction
Lifespan
Onset of maturity
Early
Late
Interplay = spawning opportunities
Number and size of eggs
Number of batches/season
Relationship with size/age
Not all eggs are the same!
Another term for sex identification
gross gonadal morphology
Female sex identification organ
Ovaries
Male sex identification organ
Testes
Physical Characteristics of Ovaries
Typically yellow or orange in coloration
Granular consistency
Vascularization
Central lumen
Physical Characteristics of Testes
Typically white or off-white in coloration
Smooth consistency
No central lumen
How can gonads help with understanding productive cycles and/or timing?
Size
Another term for assessing maturation
gross gonadal condition
What does GSI stand for?
Gonadosomatic Index
What does Gonadosomatic Index equal?
Gonad weight/somatic weight
Somatic Weight
Total body muscle - everything beyond the reproductive system.
What are some key characteristics for assessing maturation?
Gonads increase in size prior to spawning season
Remain large through spawning season
Become smaller in “resting phase”
What are the variables used to assess maturity?
Length or age at first maturity
What percentage is a standard often used to assess a population’s maturity?
Length or age at 50% maturity.
Example: 50% of the population is mature at a certain length or certain age.
What are the two stages of Ovarian Development?
Sexually Immature
Sexually mature