fish reproduction - 19.11.24

Life history

Organism's reproductive activities throughout its lifetime.

Adaptive plasticity

Ability to change traits for reproductive success.

Anthropogenic pressures

Human impacts affecting fish life histories.

Life history traits

Characteristics influencing reproductive success and behavior.

r-strategists

Species with high reproduction rates, low parental care.

K-strategists

Species with lower reproduction rates, high parental care.

Free spawning

Releasing eggs and sperm into the environment.

Egg defense

Protecting eggs from predators and environmental hazards.

Planktonic larvae

Larvae that drift in water currents.

Vivipary

Live birth instead of laying eggs.

Parental care

Investment in offspring survival post-birth.

Migration

Seasonal movement for breeding or feeding.

Sequential hermaphroditism

Changing sex during an organism's life cycle.

Endocrine disruption

Chemical interference affecting hormonal functions.

Feminization of fish

Male fish developing female characteristics.

Anadromous

Fish migrating from freshwater to marine for feeding.

Salmonid

Family of fish including salmon and trout.

Spawning adults

Mature fish reproducing in their native habitat.

Alevins

Newly hatched fish still dependent on yolk.

Smolt

Young salmon transitioning from freshwater to saltwater.

Fry

Young fish that have absorbed their yolk sac.

Parr

Juvenile salmonids in freshwater before smolt stage.

Semelparous

Species that reproduce only once before dying.

Reproductive investment

Energy and resources allocated to offspring production.

Variable migratory behavior

Different migration patterns among salmon populations.

MSW fish

Mature salmon that migrate to sea for feeding.

Atlantic salmon migrations

Movement patterns during life cycle stages.

Eurasian one sea winter fish

Salmon that spend one winter at sea.

Land-locked populations

Salmon populations that do not migrate.

Smoltification

Process of juvenile salmon adapting to saltwater.

Redds

Nesting sites where salmon spawn in rivers.

External fertilization

Eggs fertilized outside female's body.

Precocious males

Males maturing early to compete for fertilization.

Gametes contribution

Precocious males contribute 40-50% of female eggs.

Natal homing

Salmon's ability to return to birthplace.

Survival rate

Only 700 adults return from 100,000 smolts.

Genetic drift

Random changes in allele frequencies in populations.

Microsatellites

Short tandem repeat units for genetic analysis.

Pedigree reconstruction

Determining lineage through genetic markers.

Effective population size (Ne)

Number of breeding individuals in a population.

Asyncronicity of breeding

Breeding occurring at different times among individuals.

Reproductive investment

Energy allocated to reproduction by fish.

Macro-gametic sex

Sex with larger gametes, typically females.

Frequency dependent selection

Selection based on the frequency of traits.

Fishery pressure

Impact of fishing on fish populations.

Fishing mortality

Rate of fish deaths due to fishing activities.

Plasticity vs evolution

Debate on whether changes are adaptive or genetic.

Plasticity

Phenotypic response to environmental changes.

Earlier maturation

Response to reduced stock size from exploitation.

Compensatory growth

Increased growth rates due to resource relaxation.

Evolutionary advantage

Older spawners produce larger, more viable eggs.

Fishing impact

Targets larger fish, disrupting fitness advantages.

Natural selection

Favors early-maturing phenotypes despite lower fertility.

Genetic make-up

Influences maturation age and size in fish.

Fishery pressure

Long-term reduction needed for late-maturing recovery.

Reaction norm

Phenotypic expression pattern across environments.

Sexual maturity variance

Variation in size at maturity within populations.

LP50

Length for 50% probability of maturation.

Teleost populations

Exhibit phenotypic variation in life history.

Fishing mortality

Selection pressure affecting fish maturation traits.

Complex genetic trait

Maturation timing influenced by multiple genetic factors.

GWAS studies

Genetic analysis to understand maturation changes.

Sequential hermaphroditism

Change sex from male to female or vice versa.

Protandry

Starts as male, later becomes female.

Protogyny

Starts as female, later becomes male.

Simultaneous hermaphroditism

Possesses both male and female reproductive organs.

Size advantage model

Larger individuals have reproductive benefits.

Low density model

Simultaneous hermaphroditism in low population densities.

Anthropogenic gender modification

Human activities altering fish reproductive strategies.

Gonochorism

Fixed male or female reproductive roles.

Endocrine disrupting chemicals (EDC)

Chemicals affecting hormonal systems in organisms.

Estradiol (E2)

A potent estrogen hormone from human waste.

Estrone (E1)

A weaker estrogen hormone from human excreta.

17 alpha-ethinylestradiol (EE2)

Synthetic estrogen in contraceptive pills.

Feminization of male gonads

Development of female characteristics in male fish.

Intersex index

Measure of sexual differentiation in fish.

Nonintersex male fish

Males with normal testis and mature sperm.

Mildly intersex fish

Males with some oocytes among sperm.

Severely intersex fish

Males with predominance of oocytes.

Effective population size (Ne)

Estimated number of breeding individuals in a population.

Microsatellite loci

Short, repetitive DNA sequences used for genetic analysis.

Population structure

Distribution of genetic variation within a population.

Anthropogenic pressure

Human-induced stressors affecting ecosystems.

Long-term exposure effects

Prolonged contact leading to significant ecological changes.

Testicular feminization

Progressive change of male gonads towards female characteristics.

Self-sustaining populations

Populations that can maintain themselves despite challenges.

Extinction risk

Likelihood of a species disappearing from its habitat.

Flathead minnow (Pimephales promelas)

Fish species affected by synthetic estrogen exposure.

Life history strategies

Reproductive strategies influencing survival and reproduction.

Age at maturity

Age when fish can reproduce.

Gender plasticity

Ability of fish to change sex in response to environment.

Feminization impact on genetic diversity

Reduced male breeding leads to lower genetic variation.

Conservation genomics

Study of genetic diversity for species preservation.