Lecture 1 - Fish Habitats Flashcards Preview

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Flashcards in Lecture 1 - Fish Habitats Deck (41)
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1

What is a fish?

Poikilothermic, aquatic chordate with appendages (when present) developed as fins, whose chief respiratory organs are gills and whose bodies are usually covered with scales.

2

Definition of a fish:
________ aquatic ______ with appendages (when present) developed as _____, whose chief respiratory organs are _____ and whose bodies are usually covered with ______.

Poikilothermic
Chordate
Fins
Gills
Scales

3

What does poikilothermic mean?

Internal temperature regulated by the environment.

4

What are the two reasons that fish are not cold blooded?

1 - Fish in warm water have warm blood
2 - Some fish (e.g. tuna) can increased their body temperature above ambient using different sorts of muscles to heat blood up

5

A chordate is any animal with ____ ____ at some point in development; a dorsal _______ _____ cord; a _______ at some point in development, and a _____-_____ tail.

gill slits
hollow nerve
notochord
post-anal

6

All _______ are _______ but not all ________ are ________.
(Chordates or vertebrates)

All vertebrates are chordates.
Not all chordates are vertebrates.

7

What are the ecological factors that fish have to worry about?

Food, predation, invasive species, spawning habitats.

8

What are the environmental parameters fish have to worry about?

Salinity, how much water is present, temperature, light intensity, pH, depth, DO

9

What drives species diversity locally?

Temperature, depth (to some extent), light intensity - diel cycling, turbidity levels

10

Variation in turbidity levels can vary due to natural and anthropogenic factors. Explain.

Natural - some fish prefer murky waters and some prefer clear waters
Anthropogenic - stirring up sediment

11

Sturgeon are a massive, long-lived local fish. They were though to be locally extinct but, have a made a resurgence locally. Explain and indicate which is the most important factor.

1 - Dr. Pitcher started revamping spawning habitats
2 - Decreased turbidity (most important.
3 - Increased quality of environmental parameters

12

What are the outer ranges of salinity in which fish can survive.

0 - 140 ppt

13

At 140 ppt, what occurs?

Salt crystallizes out of solution

14

Why does depth matter? i.e. what factors are related to depth?

1 - Light (the deeper you go, the less light there is)
2 - Temperature (Deeper water will generally be colder' up to a certain point)
3 - Pressure - increases linearly with depth (1atm/10m)

15

Describe the temperature ranges in which fish can be observed.

-2°C to 40°c

16

What are the issues at the upper range of the temperature spectra? The lower range?

High temps. - cellular degradation and denaturation of proteins
Low temps - freezing

17

Most fish do better at ____ temperatures than _____ temperatures.

high
low

18

There is roughly ____ distribution of fish species between marine and freshwater systems, however there are more in ______ environments compared to _________.

even
marine
freshwater

19

Why are there more marine fish than freshwater fish?

1 - Fish evolved in marine environments and then moved to freshwater
2 - There is more seawater than there is fresh

20

Why is there so little freshwater?

Much of the freshwater is unavailable under the form of glaciers

21

What drives species diversification in freshwater?

These are highly productive environments.

22

Why are freshwater environments highly productive?

Lots of nutrient input from land

23

_________ drives species diversification. (Related to food)

Productivity

24

What areas are productive in strictly marine environments?

Coastal zones

25

What is an estuary? What type of water is located there?
What are they important for?

Estuaries are a combination of both fresh and saltwater and are the locations where freshwater meets the ocean.
They are composed of brackish water, i.e. are within 0-32 ppt (32 being open ocean and 0 being freshwater)

Estuaries are important nursery grounds for marine fish.

26

Define a lotic environment.

High flowing environment with lots of water flow. River or stream.

27

Define a lentic environment.

Low flowing environment. Characteristics of a lake.

28

Why do we care about flow?

It can drive species diversification since flow affects morphology.
In a higher flow environment, the fish needs to be more hydrodynamic.
In a lake system, the fish can be more blobbed shaped.

29

What are the different oceanic habitats (related to depth)?

Pelagic
-epipelagic
-mesopelagic
-bathypelagic
--Abyssal
Benthic/Benthal

30

What does pelagic mean?

Generally refers to the open water. i.e. the top and not the bottom

31

What does benthic mean? Benthal?

Fish associated with the bottom.
Officially, benthic means the bottom and benthal means near the bottom.

32

In the ocean, the pelagic zone is split into three zones. These are?

Epipelagic, mesopelagic, bathypelagic

33

Describe the epipelagic zone.

-Top layer, ranging from 0-200m in depth.
-Most oceanic fish are found here
-lots of biomass
- photosynthesis is higher than respiration
-also called the euphoric zone - means that light is not limiting during the day

34

Describe the mesopelagic zone

-Roughly from 200m-1000m in depth
-Light is available throughout most, if not all, of the water column
-light attenuates as depth increases
- vision can still be used here
- photosynthesis is less than respiration
- reduction in biomass with depth
- permanent thermocline

35

As we go deeper in the mesopelagic what occurs? What adaptations has this caused?

3 things:
1 - Reduction in light
-->fish will have larger and larger eyes. Adaptation allowing for more sensitive vision to catch every photon of light
2 - Reduction in biomass
--> fish have to be more efficient at hunting
--> mechanisms to reduce metabolic demand
3 - Permanent thermocline
--> deeper is colder
--> species will choose where to live in water column based on preferred temperature

36

What is a reason that there is a permanent thermocline in the mesopelagic?

Too deep for surface mixing

37

Describe the bathypelagic zone.

- Anything below 1000m
- no sunlight
- reduction in eyes
- sensory adaptations to take over loss of eyesight
- always cold, no thermocline
- no seasonal cycling in temperature

38

What are the issues bathypelagic fish face?

Cold, dark, poor amount of food, hard to find mates

39

What is the term used for really deep living fish? What zone is it part of?

Abyssal, part of the bathypelagic

40

Describe the abyssal zone

- Below 4000m
- fish live in open gashes on the sea floor

41

What is the deepest fish have been observed?

8300m