Fish Bio Final

What are the differences in digestive anatomy between piscivores, planktivores, and herbivores?

Piscivores have large stomachs and short intestines; planktivores have smaller stomachs and moderate intestines; herbivores have gizzard-like stomachs and long, complex intestines

Why do gill rakers differ between piscivores and planktivores?

Gill rakers are adapted to prey size; planktivores have long, tightly spaced rakers to filter small prey, while piscivores have short, sparse rakers for large prey.

Why does digestive anatomy differ between herbivores and carnivores?

Herbivores have long intestines to process plant material, while carnivores have shorter intestines and larger stomachs.

What are biases of using stomach contents to assess diet?

Prey identification issues, missing prey items, and accumulation of indigestible prey.

How are stable isotopes used to examine fish diet?

Carbon values indicate prey source and nitrogen values indicate trophic level; interpreted using a C–N biplot.

What is recruitment?

New additions to a population or fishery.

What does semelparous mean?

Spawning once and then dying (e.g., salmon).

What does iteroparous mean?

Spawning multiple times over a lifetime.

Why do small increases in early-life survival greatly increase recruitment?

Individuals mature earlier, enter the population sooner, and reproduce earlier.

Why do males often mature earlier than females?

Females require more energy and larger bodies to support egg production.

What is cuckoldry in bluegills?

Sneaker or female-mimic males reproduce by stealing fertilizations from parental males.

What is sequential hermaphroditism?

Sex change during life; protogynous = female to male, protandrous = male to female.

What is the difference between determinate and indeterminate spawners?

Determinate spawners produce a fixed number of eggs before spawning season; indeterminate spawners continue egg production during the season.

What is absolute fecundity?

Total number of eggs produced per female or spawning event.

What is relative fecundity?

Absolute fecundity divided by body weight.

How is GSI calculated?

(Gonad mass ÷ ovary-free body mass) × 100.

What is ovipary?

Eggs and sperm released into the environment; external fertilization.

What is vivipary?

:: Internal fertilization with placental development and low fecundity.

What is ovivipary?

Internal fertilization with eggs retained and nourished by yolk.

What are the pros of broadcast spawning?

No parental energy cost after spawning and high dispersal.

What are the cons of broadcast spawning?

Low offspring survival.

What are demersal guarders?

Species that spawn in nests and provide parental care.

What are the pros of demersal guarding?

Greater offspring survival due to protection.

What are the cons of demersal guarding?

High parental energy costs and risk of losing entire brood.

What are the five stages of fish development?

Embryonic, larval, juvenile, adult, senescent.

What is Early Life History?

Early stages of life which include egg incubation & hatching

Important because most fish develop rapidly from eggs -> larvae -> juveniles

What is the difference between altricial and precocial larvae?

Altricial larvae are less developed; precocial larvae develop rapidly and resemble adults.

How does early-life growth affect survival?

Faster growth increases survival and recruitment.

What causes mortality in fish larvae?

Predation, starvation, and advection.

What is the “critical period” in larval fish?

A time when limited food availability determines survival and recruitment success.

What is the match-mismatch hypothesis?

Survival depends on overlap between larval presence and food availability.

What biotic factors influence recruitment?

Stock size, food availability, predation.

What abiotic factors influence recruitment?

Temperature, wind, waves, and environmental conditions.

What are life history traits?

Growth rate, age at maturity, fecundity, parental care, spawning frequency.

What is a life history trade-off?

A compromise between traits such as offspring number versus size.

What is bet-hedging?

A strategy that reduces reproductive risk across variable environments.

What defines r-selected species?

Early maturation, small eggs, high fecundity, little parental care.

What defines K-selected species?

Late maturation, large eggs, fewer offspring, high parental care.

What are the three Winemiller & Rose strategies? :: \

Equilibrium, opportunistic, and periodic

What is a population?

A group of interbreeding individuals of the same species.

What is the population equation for a closed population?

N = births − deaths.

What is the population equation for an open population?

N = (births + immigration) − (deaths + emigration).

What is density independence?

Population size is unaffected by population density.

What is density dependence?

Population size is affected by density.

What is compensation?

Individual growth and survival decrease as population size increases.

What is depensation?

Individual growth and survival increase as population size increases.

What are species distributions?

The geographic area where a species occurs.

What defines a species’ optimal range?

Regions where fitness and vital rates are highest.

What are the three thermal guilds?

Warm stenotherms, eurytherms, cold stenotherms

What is diel vertical migration (DVM)?

Daily movement up and down the water column.

What is anadromous migration?

Fish migrate from saltwater to freshwater to spawn.

What is catadromous migration?

Fish migrate from freshwater to saltwater to spawn.

What cues do fish use for migration?

Olfactory, visual, chemicophysical, geomagnetic.

What is competition?

Inhibition of access to a limited resource.

What is a fundamental niche?

The full potential range a species could occupy without competition.

What is a realized niche?

The actual range occupied due to biotic limitations.

What is competitive release?

Niche expansion when competitors are absent.

What is competitive displacement?

Niche contraction due to competition.

What defines a community?

Populations of species occurring together in space and time.

What is species richness?

Number of species present.

What is evenness?

How evenly individuals are distributed among species.

What is cultural eutrophication?

Nutrient enrichment from human sources causing high productivity.

What is island biogeography?

Species richness depends on isolation and size of habitat.

What characterizes freshwater fish communities?

Closed populations and lower dispersal.

What characterizes marine fish communities?

Mostly open populations and higher dispersal.