Oceanic Nekton

Question 1

Adaptations of oceanic nekton

Answer 1

Buoyancy 
locomotion 
surface of resistance and body shape 
defence and camouflage 
sensory systems
echolocation 
reproduction lifestyle 
migrations

Question 2

What are protogynous hermaphrodites? (With example)

Answer 2

Start off female

E.g. Parrotfish

Question 3

What are protoandrous hermaphrodites? (With example)

Answer 3

Start off male

E.g. Clownfish

Question 4

What does diadromous mean?

Answer 4

Organism is both freshwater and marine

E.g. Salmon

Question 5

What does anadromous mean?

Answer 5

Adults return to freshwater (from marine)

E.g. Salmon

Question 6

What does catadromous mean?

Answer 6

Adults return to marine to spawn (from freshwater)

E.g. Eels

Question 7

What is a method of colour camouflage in netritic fish?

Answer 7

Counter-shading colouration

• dark on top (blends with darkness of depths)
• shiny on bottom (blends with light/sun)

Question 8

What does a high aspect caudal fin ratio mean? (With example)

Answer 8

Fast swim pace but short distance

E.g. Tuna

Question 9

What does a low aspect caudal fin ratio mean? (With example)

Answer 9

Short rapid acceleration but long distance

E.g. Cod

Question 10

What does white muscle mean?

Answer 10

Poor muscle blood supply

Question 11

What does dark muscle mean?

Answer 11

Good muscle blood supply

Question 12

What do the median fins do?

Answer 12

Aid stability

Question 13

What types of lift are there?

Answer 13

Buoyancy

Hydrodynamic

Question 14

What aids hydrodynamic lift?

Answer 14

Fins & tail

Question 15

What aids buoyancy?

Answer 15

Swim bladder/oil-rich liver

Question 16

What is globiform?

Answer 16

Fish shape like a ball - e.g. Pufferfish

Question 17

What is fusiform?

Answer 17

Fish streamlined and built for speed - e.g. Tuna

Question 18

What is sagittiform?

Answer 18

Arrow-like shape - e.g. Needlefish

Question 19

What is compressiform?

Answer 19

No width, laterally flattened - e.g. Flatfish

Question 20

What is depressiform?

Answer 20

No depth, dorso-ventrally flattened - E.g. Manta ray

Question 21

What is anguilliform?

Answer 21

Elongated, rounded body - e.g. Eels

Question 22

What is taeuiform?

Answer 22

Ribbon-shaped

Question 23

What is filiform?

Answer 23

Filament-like

Question 24

where is the epipelagic zone?

Answer 24

0-200m

Question 25

where is the mesopelagic zone?

Answer 25

200m-1km

Question 26

where is the bathypelagic zone?

Answer 26

1km-4km

Question 27

where is the hadalpelagic zone?

Answer 27

>4km

Question 28

where are benthicpelagic organisms found?

Answer 28

sea floor and water column to feed

Question 29

where are benthic organisms found?

Answer 29

sea floor/in sea bed

Question 30

where are pelagic organisms found?

Answer 30

in the water column

Question 31

where is the littoral zone?

Answer 31

between the high and low tide, exposed and submerged for different portions of the day

Question 32

where is the netritic zone?

Answer 32

from the low end of low tide to when the continental slope slopes down steeply

Question 33

order of seafloor names from coast to ocean

Answer 33

``` coast continental shelf continental slope continental rise abyssal plain ```

Question 34

what is a key adaptations for the neritic zone?

Answer 34

protections from irritation by pollutants | e.g. membrane across eyes of squid to protect from irritants

Question 35

what does holopelagic mean?

Answer 35

fish that spend whole life in pelagic zone

Question 36

what does meroplanktonic mean?

Answer 36

fish that spend part of life in pelagic zone

Question 37

where did most fishing historically occur?

Answer 37

the pelagic zone - deeper depths only recently

Question 38

what is the visual-interactions hypothesis?

Answer 38

The metabolism of several animal groups declines with depth even after adjustments for size and temperature. why? as the result of declining light levels that reduce the distances over which predators and prey interact. - > relaxes the selective pressure for locomotory capacity - > reductions in metabolic

Question 39

where is the visual-interactions hypothesis most pronounced and why?

Answer 39

pelagic species - no refuge from predators. | -> less depth-related variation among benthic species.

Question 40

what is a small-scale example of a regime shift?

Answer 40

coral reefs - coral dominated VS algae dominated Hurricane Allan in Caribbean -> rainfall reduced water salinity -> coral deaths -> algae dominated coral reefs

Question 41

what is an intermediate-scale example of a regime shift?

Answer 41

North Sea - more water from Atlantic Ocean - > changes in plankton community - > more jelly fish but less cod - > less herring and haddock (juvenile predated by jellyfish)

Question 42

what is a large-scale example of a regime shift?

Answer 42

North Pacific Ocean - warming in the Winter Pacific Oscillation (starting in mid 1970s) -> reduction in Chinook salmon but increase in pink salmon

Question 43

what is a behaviour of fish species which can reduce by-catch percentages?

Answer 43

shoaling (all together)

Question 44

when calculating swim speed for fish what is Hz referring to?

Answer 44

number of tail flicks a second

Question 45

what is a physostomous swimbladder?

Answer 45

open to gut- gulp air

Question 46

what is a physoclistous swimbladder?

Answer 46

closed

Question 47

what is a swimbladder solution to increased pressure with depth?

Answer 47

rigid container

Question 48

what is a pattern on the distribution of fish with swimbladder?

Answer 48

more swimbladder fish closer to the surface

Question 49

What is a method of shape camouflage in netritic fish?

Answer 49

keel - sharp ventral edge tail | e.g. tuna

Question 50

sharks and rays special sensing organ

Answer 50

ampullae Lorenzini | electrical signals

Question 51

amphidromous

Answer 51

migrate for purpose other than reproduction

Question 52

potamodromous

Answer 52

migrate wholly within freshwater

Question 53

oceanodromous

Answer 53

live and migrate wholly within seawater

Question 54

magnetotactic bacteria

Answer 54

use of magnetic fields in migration

Question 55

more invasive fish species tend to be...

Answer 55

planktivorous