The ecology of Fishes

Question 1

what are three adaptations polar region fish have?

Answer 1

1. most individuals are bottom oriented and visual rpedators 2. bodies tend to be elongate 3. lack swim bladders and replaced with fat deposits

Question 2

what are the pros of the food chain approach?

Answer 2

pros: linear chain used to describe transgers of energy between trophic levels

Question 3

what are three reasons why a fish would undergo a migration?

Answer 3

1. feeding 2. refuge 3. spawning

Question 4

what are the cons of the food web approach?

Answer 4

diets vary in time and space, food webs imply static conditions, small dietary items that may have importance other than colirc intake may be under represented and there are unique inputs of energy to systems that are not covered.

Question 5

what are the two types of diadromy?

Answer 5

anadromous: breed in freshwater and migrate to saltwater to grow ex.) salmon catadromous: breed in saltwater and migrate to freshwater to grow. ex.) eels.

Question 6

Fatt acid is based on what?

Answer 6

consumed lipids are usually stored as free fatty acids that are largely unchanged from those within the consumed organism

Question 7

Polar regions are characterized by?

Answer 7

cold water and relatively low productivity

Question 8

Trophodynamics:

Answer 8

the study of fluxes of nutrients and energy in ecosystems. Common in fisheries management

Question 9

how do fish prevent cellular damage in sub-zero waters?

Answer 9

anti freeze in their blood that prevents thr growth of ice crystal below certain temperatures. found in flounders, sculpins, smelts and herring

Question 10

open ocean is characterized by what?

Answer 10

vast food desert with poor nutrients and little life.

Question 11

what cues can be associated with site fidelity?

Answer 11

1. chemical cues in the water can allow for imprinting during early development. 2. environmental cues are also thought to play a role in guiding fish from out to sea back to stream entrance. like the sun or moon, magnetic fields, ocean currents, temp gradients and salinity

Question 12

what are the cons of the food chain approach?

Answer 12

Cons: many species actually feed at multiple trophic levels, unrealistic to assume constant energy tranfers across entire trophic levels can change over an individuals lifetime or even though out a year

Question 13

why are most fish cnsidered omnivores? what reasons would they have to be a generalist?

Answer 13

omnivores feeds on a variety of food types. To take advantage of opportunistic food sources.

Question 14

what are the pros of the food web approach?

Answer 14

branching web of multiple interactions between populations. Describes the feeding relationships within entire communities of organisms.

Question 15

Freshwater tropical regions are characterized by what?

Answer 15

waters are warm year round

Question 16

what are three types of analysis?

Answer 16

1. gut content 2. fatty acid 3. stable isotope

Question 17

How do the seasons differ in tropical regions from temperate regions?

Answer 17

highly affected by the wet and dry seasons of the tropics as opposed to the cold and warm seasons of temperate regions

Question 18

how do fish adapt to deep ocean mesopelagic zone?

Answer 18

1. vertical migrations at night to upper regions of ocean to feed. 2. have muscular bodiesm swim bladders and strong skeletons to make the vertical migrations and withstand the pressure. 3. large eyes 4. concealment in the dark is main defense 5. some have photopores to produce light on the bellies which works like countershading. lanterfish, sabretoothed fish, barrel eye

Question 19

fish in the bathypelagic zone are adapted for ———- lifestyle with little ——- and no ———

Answer 19

sedentary/ food/ light

Question 20

coastal habitats are characterized by?

Answer 20

harsh environments, subject to crashing surf and strong currents

Question 21

adaptations seen in fish living in coastal habitats?

Answer 21

1. reduced or absent swim bladders 2. compressed bodies- flatfish bodies prevent them from being swept away 3. ways of clingings to substrate like sculpins with their large pectoral fins

Question 22

a downside to coral reef habitat for fish is what?

Answer 22

high amounts of competition

Question 23

adaptations seen in fish living in coral reefs?

Answer 23

1. Most species are small (<30 cm long) and are sedentary, dont move from their established territory. 2. Whereas fish in most areas adapt to help them survive their physical environment, fish in coral reefs have adapted to survive in their social environment

Question 24

what is an n-dimensional hypervolume?

Answer 24

every point in which corresponds to a state of the environment which would permit the species to exist indefinitely.

Question 25

stablie isotope is based on?

Answer 25

comparing specific ratios of isotopes in fish tissues to those ratios of prey items you can assess the relative importance of major pathways in ecosystems. Commonly used to determine what tropic level an orgamisms is at. Organisms in richer carbon and nitrogen are often lower in trophic level

Question 26

what allows for a high level of speciation in freshwater tropical regions?

Answer 26

waters are warm year-round, allowing multiple generations per year, increasing rates of speciation.

Question 27

Gut content is based on what?

Answer 27

depends on gut turnover rate.

Question 28

adaptations for fish in the bathypelagic zone?

Answer 28

1. poorly developed muscles, skeletons and nervous systems because these cost too much energy and they mostly have a sedentary lfie style so dont need them. 2. move by floating around 3. either small or enormous eyes 4. can use photophores as lures liek angler fish. 5. Must be able to eat as much as possible so have large mouths with long sharp teeth to trap prey. ex.) angler fish, gulper eel

Question 29

is there any adaptations freshwater tropical region fish have?

Answer 29

not really since it is a very ideal place to live with the exception of icnreased competition from high numbers of individuals

Question 30

adaptations seen in freshwater temperate regions?

Answer 30

1. avoidance- migration away from cooler areas 2. Torpor- entering a stae of reduced metabolic activity, essentially a lighter version of hibernation ex.) carp, sturgeon 3. However, some fish remain active under the ice in the winter at the bottom of the light in the area of high water temperature like trout, salmon and suckers

Question 31

adaptations for fish that live in the open ocean?

Answer 31

1. streamlined bodies- allow for continous and rapid swimming (sharks, tuna) 2. shoaling- congregation for fish usually done for protection but also finding food. 3. Silver body colour- by both predtros and prety to scatter light and reduce the chance of being found 4. counter shading- darker on the top and lighter on the bottom so they are difficult to see form above and below.

Question 32

Migrations are?

Answer 32

syncronized movement by species that are large relative to the average home range for that species and which occur at specific stages of the life cycle.

Question 33

oceanodromy and example

Answer 33

migrations within a marine body of water. Atlantic cod migration offshore to overwintering sites.

Question 34

freshwater temperate regions are characterized by:

Answer 34

locations that typically ice over in the winter and where the ambient water temperature can fall to or just above freezing.

Question 35

why are trophic dynamics an important element of community ecology?

Answer 35

community ecology looks at the interactions between 2 or more populations. predation is an important driver of community dynamics

Question 36

trophic ecology:

Answer 36

study of how organisms interact with each other and their surroundings

Question 37

where do moest species live in the polar regions?

Answer 37

most species are benthic and sedentary

Question 38

site fidelity:

Answer 38

often these fishes rely on homing mechanisms to return to the same area they were born on, or have associated with bountiful forage

Question 39

deep ocean- bathypelagic zone is characterized by?

Answer 39

zone of complete darkness

Question 40

what place have the highest diversity of fish species?

Answer 40

coral reefs

Question 41

what is the difference between detritivores, herbivores and carnivores? provide examples of each.

Answer 41

detritivores feed on dead and on partially decomposion organic material. ex.) catfish Herbivores feed on vegetation such as algavores (herrings), frugivores Carnivores: Feed on live animals. Piscivores fish that feed on fish which is common in gamefish. Planktivores fish that feed on zooplanton and other invertebrates. juvenille fish will often start feeding on this as their gape size progresses. Insectivores: fish that feed on insects, trouts

Question 42

coral reefs are characterized by?

Answer 42

rocky crowded areas with many places to hide.

Question 43

niche:

Answer 43

a niche is an organisms functional role in an ecological community or ecosystem. The evolutionary result of a species morphological, physiological and behavioural adaptations to its surroundings.

Question 44

deep ocean - mesopelagic zone is characterized by what?

Answer 44

where the last of the light penetrates

Question 45

potadromous and example

Answer 45

migrations within freshwater bodies. Lake sturgeon will migrate from lakes or downstream reaches of river into shallower, faster waters upstream

Question 46

what is the time scale like for the types of analysis: 1. gut content 2. fatty acid 3. stable isotope

Answer 46

1. snapshot in space and time of the fish's diet 2. Weeks to months 3. Ratios persist for periods of months to years which allows for long term and legacy effects to be apparent