Quiz 5 Flashcards
Type III functional response curve
- sigmoidal
- low consumption at low prey densities until a prey threshold is reached
Functional response models
-characterize potential and actual relationships of a predator to prey availability
Reynolds number
-ratio of two inertial forces to viscous forces
= d * V/v
V = velocity
v = kinematic viscosity
Size based predation in fish
- most predators are gape-limited
- most fish cant swallow prey more than half their own body size
Ecosystem responses to fish predation
- bottom up control: nutrients and plants
- top down control: animals play a critical role
Trophic cascade
-a series of feedbacks caused by the presence or absence of piscivorous fish in lakes
Why is age an important property in fish
-allows us to understand all of the complex age-dependant processes
Chronometric structures
- means of determining a fishes age that are found within fishes
- allows us to determine fish age, growth rates, other life histories events
Examples of chronometric structures in fish
- operculum bones
- scales
- otoliths
- eye lens
- fin spines and rays
- vertebral bones
Otoliths
- 3 pairs
- sagitta (largest part)
- lapillus
- asteriscus
Annuli
-the markings on the otolith that allows us to determine the age of fish
How we measure age by otholith
- each year of growth is composed of an opaque zone
- zone is formed during rapid growth in summer periods and a translucent zone formed during winter
- Pelagic fish have smaller otolith
Three ways to cut otolith to age
- Sagittal
- Transverse
- Frontal
Pros and cons of scale aging
- PRO: dont have to kill fish / adequate for young or short-lived fish
- CON: resorption or remodling possible / can fall off and regenerate
pros and cons of otolith aging
PRO: accurate info to daily level / better for long lived fish / physiologically inert
CONS: killing / decoupling from somatic growth can occur
