Semelparous fish reproduce only once during their lifetime, typically releasing all of their eggs or sperm at once in a single spawning event.

Incubation is the process by which fish eggs hatch and develop into larvae. This can occur inside the body of the parent fish (internal incubation) or outside the body (external incubation).

Budding, fragmentation, and parthenogenesis are all types of asexual reproduction found in some fish and shellfish. Budding involves the formation of a new individual from an outgrowth of the parent's body. Fragmentation involves the breaking of the parent's body into several pieces, each of which can develop into a new individual. Parthenogenesis involves the development of an embryo from an unfertilized egg.

Incubation is the term for the period of time between spawning and hatching in fish. During this period, the eggs develop and grow inside or outside the body of the parent fish.

Water temperature, food availability, and habitat quality are all factors that can influence the reproductive success of fish and shellfish. Water temperature affects the timing and success of spawning, food availability affects the growth and development of eggs and larvae, and habitat quality affects the survival and reproductive success of adults.

Spawning is the term for the process by which fish and shellfish release their eggs and sperm into the water. This can occur in a variety of ways, including through external fertilization (where the eggs and sperm are released into the water and fertilized externally) and internal fertilization (where the eggs are fertilized inside the body of the female).

Salmon are a type of fish that exhibits parental care. After spawning, the male and female salmon will guard the eggs until they hatch and the fry emerge. The parents will also defend the fry from predators and help them find food.

Metamorphosis is the term for the process by which fish and shellfish larvae transform into juveniles. During metamorphosis, the larvae undergo a series of physical and physiological changes that prepare them for life as adults.

Clams, oysters, and mussels are all types of shellfish that reproduce through external fertilization. During spawning, the males and females release their eggs and sperm into the water, where fertilization takes place.

The juvenile period is the term for the period of time between hatching and sexual maturity in fish and shellfish. During this period, the juveniles grow and develop, and they may undergo a series of physical and physiological changes.

Water temperature, photoperiod, and social interactions can all influence the sex of fish and shellfish. Water temperature can affect the sex ratio of offspring, photoperiod can trigger sex changes in some species, and social interactions can influence the sex of offspring in some fish species.

Gametogenesis is the term for the process by which fish and shellfish produce eggs and sperm. This process involves the formation and maturation of gametes (eggs and sperm) in the gonads (ovaries and testes).

Sharks are a type of fish that exhibits internal fertilization. During mating, the male shark inserts his claspers into the female's cloaca and transfers sperm into her reproductive tract. The eggs are then fertilized internally.

The adult period is the term for the period of time between sexual maturity and death in fish and shellfish. During this period, the adults reproduce and care for their young.

Pollution, habitat destruction, and overfishing can all influence the reproductive success of fish and shellfish. Pollution can contaminate the water and make it unsafe for fish and shellfish to reproduce. Habitat destruction can reduce the amount of suitable habitat available for fish and shellfish to reproduce. Overfishing can reduce the number of adults available to reproduce.