L 19 Deep bodied fishes

Question 1

What is the difference between a pelagic and benthic environment?

Answer 1

Pelagic env -water itself

benthic - bottom of the ocean environment

Question 2

The pelagic environment is divided in two zones? What are they?

Answer 2

1. netiric

2. oceanic

Question 3

What is the neritic zone?

Answer 3

it extends from the intertidal region seaward. includes water overlying the ocean bottom that’s less than 200 m in depth. This corresponds on average to the margin of the continental shelf

Question 4

What is the oceanic zone like?

Answer 4

includes all water overlying the continental slope and ocean bottom beyond the margin of the continental shelf

Question 5

the Oceanic zone is further divided into four zones, what are they?

Answer 5

1. epipelagic
2. mesopelagic
3. bathypelagic
4. abyssopelagic

EMBA, or BEAM

Question 6

What is the epipelagic zone like?

Answer 6

From surface to 200 m, a depth that corresponds on average to the margin of the continental slope,

it is approx equivalent to the lower limit of photosynthesis

Question 7

What is the mesopelagic zone?

Answer 7

extends from 200 to 1000 m

the greater depth corresponds to the limit of penetration of solar radiation, often called the twilight zone

Question 8

What is the bathypelagic zone like?

Answer 8

from 1000 to 4000 m below the extent of solar radiation

Question 9

What is the abyssopelagic zone like?

Answer 9

deepest part of the ocean below 4000m

Question 10

What is the distribution of fishes like in the epipelagic zone?

Answer 10

provides habitat for approx 250 resident fishes

includes large preaceous forms like tunas, mackerls and pelagic oceanic sharks.

also serves as nursery for tons of eggs and larvae of deep living forms.

Question 11

What does mesopelagic zone supprot?

Answer 11

approx 850 fishes, mostly silvery forms with large eyes, to which nearly are all bioluminescent

Question 12

What kind of fishes does the bathypelagic zone support?

Answer 12

about 280 species, most are black fishes with small or degenerate eyes, poorly developed musculature and weakly ossified skeletons

examples are gulper eels and deep sea angler fishes

Question 13

What kind of fishes are usually in the abyssopelagic zone?

Answer 13

about 1350 species,

includes hagfishes, certain squaloid sharks, deep sea skates and some chimaeras

Question 14

What are some environmental parameters to the vertical distribution of oceanic fishes?

Answer 14

1. primary organic production
2. solar radiaton
3. temperature
4. pressure

Question 15

What occurs to primary organic production as depth increases?

Answer 15

decrease in primary organic production

Question 16

When does photosynthesis stop occuring?

Answer 16

about 200 m.

Solar energy disappears at the depths of about 1k m

Question 17

What are deep sea fishes like? Size and population size?

Answer 17

Size and mass of individual is reduced due to lack of sunligh, and loss of primary organic production. Smaller you are the less you need to it.

there is also smaller population sizes?

Question 18

What are some characteristics of deep sea fishes’ organ systems?

Answer 18

• poorly ossified skeletons

2. soft degenerate muscles and reduced organ systems

Question 19

What may be the reason for bathypelagic deep sea fishes for not having a swimbladder?

Answer 19

Since they spend all their lives on the deep sea floor. There isn’t a need for a hydrostatic organ.

swimbladders are also metabolically expensive to operate

Question 20

How does communication occur in the mesopelagic zone?

Answer 20

Predominately through light organ systems.

95% of fishes have bioluminescent organs of some kind.

They also have sensitive.

Question 21

How may photophores function?

Answer 21

1. to attract mates
2. food acquisition, to lure prey
3. predator avoidance - to startle or confuse predators, to mislead predators

Question 22

How may fishes communicate in the bathypelagic zone?

Answer 22

• there is hardly any light, eyes become degenerate and biomass drops below a tenth of meso fishes.
• fishes do not hang out in a school together, so there’s no need for communication. Olfaction is developed to help males locate females.

Question 23

What is olfaction?

Answer 23

Mechanisms developed for males to locate females

Question 24

What does macrosmatic mean?

Answer 24

-greatly enlarged olfactory organs

Question 25

What does microsmatic mean?

Answer 25

small olfactory organs

Question 26

What may be evidence that the bathypelagic zone is a silent region?

Answer 26

1. absence of swimbladders

2. drumming muscles

Question 27

How may fishes near the bottom of the deep ocean communicate?

Answer 27

sonic mechanisms