Lecture 14 - Fish Reproduction

Ovaries

Paired, large and yellowish, comprising 30-70% of the fish's weight during reproductive periods.

Testes

Smooth, white structures that can make up to 12% of body weight during reproductive periods.

Sexual Dimorphism

Changes in size or shape.

Dichromatism

Changes in color.

Tubercles

Present only on male Creek Chubsuckers during breeding season, made of keratin, and used for species recognition, fighting, and nest defense.

Cleavage

Early cell division

Blastula

Hollow ball of cells

Epiboly

Ectoderm spreads and thins, mesoderm and endoderm move to the inside

Gastrula

Process where the endoderm, ectoderm, and mesoderm form. Refers to the formation of the gut.

R-Selection

A selective strategy favoring large numbers of offspring, short lifespans, small size, and little parental care.

K-Selection

A selective strategy favoring few offspring, long lifespans, large size, and long-term parental care.

Embryonic Period

The developing individual is entirely dependent on nutrition provided by the mother.

Larval Period

Begins when the fish is able to capture food and ends when the axial skeleton forms.

Juvenile Period

Organs fully formed, but gonads not mature.

Anadromous Life Cycle

Spawn in freshwater, grow in saltwater

Redd

Nest dug by female salmon using their tails.

Alevin

Term for salmon eggs

Fry

Term for when Alevin leave the nest.

Catadromous Life Cycle

Live in freshwater and spawn in saltwater

Non-Guarders

Do not protect their eggs and young after spawning.

Guarders

Fish that guard embryos until they hatch, and sometimes care for larval stages.

Bearers

Fish that carry their embryos and sometimes their young around with them.