Ecology of Fishes Flashcards
Describe three life history strategies with fish examples?
Opportunistic: low juvenile survival, low fecundity, early maturity: guppies
Periodic: low juvenile survival, high fecundity, late maturity: sturgeon
Equilibrium: high juvenile survival, low fecundity, late maturity: shark
What are the three survivorship curves with fish examples?
I: few offspring and high consistent survival until older age: Sharks
II: consistent survival/death from birth to death
III: many offspring with high death until older age: Most fish
Define population
A group of the same species that interbreed and live in the same area
Define assemblage
Taxonomically related group of species populations that occur together in space
Define guild
A group of different species that use the same resources
Define community
all coexisting unrelated and related organisms that live within the same place
Define recruitment
The process of larvae settling down and joining a population
Define ontogenetic niche shifts and give an example
An ecological event where an organism changes its diet or habitat. This could be because of the introduction of another organism into the habitat or naturally occurs during growth. For example, most herbivorous fish start off as carnivorous, become omnivores while a juvenile, and the adult form is herbivorous.
Largemouth bass starts off as a planktivory, than eats littoral invertebrates, and than becomes a piscivorous as an adult.
How have modern genetics changed our understandings of species and population boundaries?
Modern genetics have allowed us to identify if some fishes are one population or many: Large tuna, American eels, pacific salmon.
What is an example of competitive displacement and resource partitioning in fish communities?
Competitive displacement where one species is diminished or outcompeted by another is shown between the introduction of brown trout and the effects on the native brook trout. This competition can lead to adaptive radiation as shown in sticklebacks within the coastal lakes of British Columbia. Bluegills have shown resource partitioning by splitting up an area so no one has to compete for the same resources.
What is a trophic cascade? Give an example
A trophic cascade is a bunch of indirect interactions within a food web resulting from an addition or removal of top predators. For example, a reduction in the amount of cods can lead to a higher density of skates and rays.
What is a cross-boundary linkage?
When changes within aquatic (or terrestrial) habitats end up affecting terrestrial (or aquatic) habitats.
Explain the longitudinal zonation in streams(orders 1-7+).
Headwaters, or first permanent tributaries, are order 1. The number increases every time two streams with the same value meet. Two level 1 headwaters meet to create a level 2. However, a 2+1 will remain the larger number, a 2, and not move up to the next level. Headwaters are typically defined as 1-3, midreaches 4-6 and larger river 7+.
