lecture 10 - Fish Reproduction & Intertidal Adaptations

ICHPTHYOLOGY

What does "gonochoristic" mean?

Species with separate sexes—distinct males and females.

What are the two types of hermaphroditism in fish?

Synchronous (both sexes at once) and sequential (sex change over time).

What is protandry?

A form of sequential hermaphroditism where the fish starts as male and changes to female.

Give examples of protandrous fish

Anemonefish, moray eels, pogies.

What is protogyny?

Fish start as female and change to male—common in territorial systems where larger size benefits males.

Give examples of protogynous fish

Angelfish, gobies, groupers, wrasses, parrotfish, porgies, hamlets.

Give examples of synchronous hermaphrodites

: Groupers, porgies, hamlets.

How do reproductive strategies differ in Actinopterygians vs. Chondrichthyans?

Actinopterygians produce many small eggs; Chondrichthyans produce fewer eggs but invest heavily in offspring.

What is a batch spawner

Fish that release eggs multiple times in a season to spread reproductive risk.

Why are juvenile fish often found in different areas than adults?

Juveniles require protected areas with food and shelter—these are often separate from adult habitats.

What is a stock in fisheries biology

A reproductively distinct population of the same species, often with independent spawning sites.

What is semelparity?

Spawning once in a lifetime (e.g., some deep-sea fish).

What is iteroparity?

Reproducing multiple times throughout life.

How does fishing affect maturity in fish populations?

Creates selection pressure for earlier maturity due to decreased competition and survival.

What is oviparity in fish?

Laying eggs externally, often with no parental care—most common strategy.

When does parental care occur more frequently?

In intertidal and freshwater species with no planktonic stage.

What are examples of parental care behaviors?

Site selection, nest building, territory defense, courtship, and egg guarding.

---

How do chondrichthyans reproduce?

Internal fertilization using claspers; oviparous, ovoviviparous, or viviparous depending on species.

---

What is ovoviviparity?

Eggs hatch inside the female’s body and young are born live.

What is viviparity?

: Young develop in the uterus and are nourished via a placenta; live birth.

What challenges do intertidal fish face

Temp/wave variation, desiccation, oxygen and salinity changes, and predation.

---

What adaptations allow intertidal fish to survive?

Thick skin, body shape for crevices, eurythermy, euryhalinity, air-breathing organs, and camouflage.

What respiration adaptations do intertidal fish have?

Reinforced gills, accessory respiratory organs, and cutaneous respiration.

What is non-reproductive territoriality?

Defense of food sources or shelter—not related to reproduction.

How do mudskippers mark territory?

Build walls; have puffy cheeks with respiratory function.

Why is spatial awareness important for intertidal fish?

To return to home pools; requires strong vision and olfaction.

What is the role of the intertidal zone for non-residential fish?

Nursery area—provides shelter and feeding grounds for juvenile development.