Fish Biology

Life Cycle

Reproductive BiologyChapter 9

Fish Life Cycle

How common is parental

care in fishes?

1. Ubiquitous

2. Very common

3. Uncommon

4. Absent

Why?

Reproductive ‘Units’

Dioecious

Gonochoristic

Lepomis megalotis

Eggs & Milt

Embryo

Water hardening (0-48 hrs)

Tender stage

Eyed stage (a little more hardy)

Ends with hatching

Where does the embryo get energy

(food) if not inside female?

1. Absorption

2. Chemosynthesis

3. Yolk

4. Phytoplankton

5. Zooplankton

6. Photosynthesis

Embryo 3 days

Embryo 6 days

removed from

egg membrane

Embryo 8 days

Larva 17 days

6 mm

7 mm

10 mm

Larval Period

Begin exogenous feeding

Yolk sac (sac fry; alevin; pro-larvae)

Swim up phase

Larval feeding

opportunity

Plankton availability

Larval

predation risk

Win

do

w

Where does a larval

fish get its food?

1. Egg

2. Plankton

3. Yolk

4. Doesn’t need any

5. Plankton and / or Yolk

Juvenile Stage

YOY

Fry

Fingerling

Parr

Smolts

End at gonad development

Adult Stage

Gonads

Reproductive

Behaviors

Senescent Stage

Cohort

What is “trophic ontogeny”?

1. Change in size

2. Change in sex

3. Transformation from larvae to juveniles

4. Change in feeding with development

5. Shift in prey species present

Egg Fertilization and Incubation

Oviparous

Ovoviviparous

Viviparous

Evolutionary Continuum

Gonopodium

Parity

Semelparity

Iteroparity

Single vs. Multiple Batch

Most spawn once in spring

Factors that Induce Spawning

A good example – paddle fish

Spawning—how to pass on genes

Mass Spawning

Pair Mating

Polyandry / Polygyny

Parent vs. cuckoldry in bluegills

Sequential hermaphroditism

Bluegills – alternate strategies

Parental (dominant) nest guarding males

Parental (dominant) females

Parasitizing (functional male) cuckolders

– Sneakers

– Satellites

Neff 2013

Eggs Types

Adhesive

Non-adhesive

Floating

Demersal

Fecundity: indicative of…

…parental care, egg

size, spawning habit

Fish, frogs, toads

– r-selected species

– K-selected species

Relative Fecundity

Why measure it?

Is there a link between

fecundity and harvest?

Life Cycle and

Reproductive Requirements

Habitat and spatial arrangement of its

critical components

– Food

– Water (temp)

– Cover

– Reproduction

Diadromy

– Anadromous

– Catadromous

Sculpins attach eggs to

underside of cobbles.

Nests are defended by

solitary males until

young disperse as

juveniles.

Examples

Darters

Egg mimics I’m good at

this; mate with me…”

Sunfishes and basses excavate small

depressions and defend nests from predators.

Salmonids construct

redds, broadcast spawn

over them, and leave

eggs to the vagaries of

life.

Cyprinid Spawning Mounds

(probably constructed by a

central stoneroller, Campostoma

anamolum)

Used by a mixed species

assemblage

Chain Pickerel

Randomly scatter eggs over vegetation

Don’t really protect them

Splash tetra

Complementary vs.

Supplementary Habitats

Complementary Habitat: necessary

Supplementary Habitat: unnecessary

Example