Fish Reproduction Flashcards
Monomorphic sexes
One form; cannot tell the difference between male and female most of the year (during breeding season you might be able to tell a difference).
Normal vertebrate reproduction and normal fish reproduction.
Separate sexes: 1 male, 1 female.
Why might a fish have dimorphic sexes?
For competition: Defense or reproduction.
Name a fish which uses dimorphism for defensive purposes.
Swordtail
Name a couple fish that use dimorphism for reproduction.
Guppy and Betta- colorful males and dull females.
What is another name for betta?
Siames fighting fish.
Describe the sexual dimorphism between Angler fish.
The male is very tiny compared to the female and lives as a parasite attached to her body. His gills and fins atrophy away and hebecomes absorbed into her body. She might have several on her. Bump into rock to wake him up for reproduction.
What do Deep-Sea Angler fish use to lure fish? Why?
They have a light. They are under 7 atmospheres of pressure and need something that other fish can see and be attracted to.
Hermaphrodite
An alternative to separate sexes. A single individual, either simultaneously or sequentially, has both eggs and sperm at the same time.
What other creatures besides fish show hermaphroditism?
Earthworms, slugs, and snails. This is not seen in many verts.
What are simultaneous hermaphrodites?
They have ovaries and testes at the same time. Theoretically they could cross fertilize at the same time, but fish do not usually do this.
Name a simultaneous fish hermaphrodite.
Black Hamlet
What other creatures besides fish are hermaphrodites (and actually do cross fertilize)?
Earthworms and tapeworms
What is sequential hermaphroditism?
Start out life as one sex and change to the other. This is hardwired: A species will start out as male and a DIFFERENT species will start out as female.
Protangry
Start out as a male, turn into a female.
Which is more common protandry or protogyny?
Protogyny is found in 3/4 of hermaphrodites.
Why would a fish use protandry?
It takes a lot of energy to lay big eggs and you have to lay a lot to be effective; this takes a big female. So it is important that the fish start out as a male and be a female when bigger.
Protogyny
First female, later become male.
Why use protogyny?
In species that do not lay a lot of eggs, you need big males to be defensive; take care of the babies and defend the nest.
Int what kind of fish do you find protogyny?
Territorial fish like parrot fish and marine angel fish.
Facultative hermaphroditism.
On demand gender switching. This is done in response to hormonal cues- “no males around, I will be male”.
Facultative Protogyny
First female. Do not live long after changing; it is usually only to lay eggs or for defense. Pretty fish are dominant.
Give an example of facultative protogyny.
Swordtail. The dominant male spends a lot of energy and dies prematurely, then the dominant female changes over to be he dominant male.
Facultative Protandry
Dominant female dies and dominant male changes over.
What is a fish that does facultative protandry?
Clown fish
True or False. Pre-mating behavior is important in fish, but in general unceremonial.
True
True or False. Fish are good parents.
False
Name a fish that is territorial.
Stickleback fish
Three things involved in pre mating.
Territoriality, Nest construction, courtship
How are mudskippers territorial?
They wait for the high spring tide to lay their eggs and then fight over the sand areas for a place for the female’s eggs.
What kind of nest does the Siamese fighting fish lay?
Bubble nest. He goes up to the surface and gets air to make bubbles.
Who often builds the nest, the male or female?
Male.
What do mast fish around here do for a “nest”?
Simply clear a little area and hope the female comes along and likes it.
