Fishing Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the photic zone?

A

An area which light can penetrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is by catch?

A

The non target organisms that are caught when fishing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is upwelling?

A

A process where deep, cold water rises to the surface and transports nutrients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is the density of the sea affected in colder temperatures?

A

Increased density.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the abiotic factors and biomass in tropical oceans (temp &light)?

A

Temp- minimal seasonal changes
Light- minimal seasonal changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the abiotic factors and biomass in temperate oceans (temp, light & nutrients)?

A

Temp- seasonal changes
Light- seasonal changes
Nutrients- less nutrients in summer as there is less disturbance from storms etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the abiotic factors and biomass in polar oceans (temp, light & nutrients)?

A

Temp- cold all year round
Light- dark & light periods
Nutrients- upwellings and storms so high nutrients. Less thermal stratification.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is thermal stratification?

A

The water on the surface of the water is heated by the sun. This means that it becomes less dense so doesn’t sink (as colder water is more dense). Therefore the surface water remains on the surface and the water below stays cold and stays below the surface water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is continental margin upwelling?

A

As the wind blows along shore (parallel from the coastline) it can push coastal surface out to the sea and cause coastal upwellings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the primary production of open ocean?

A

Often low due to thermal stratification (less waves so surface heated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where are the two places ocean upwelling can occur?

A

Along continental margins.
In the middle of the ocean where there is current divergence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can ocean upwelling cause?

A

Affect in temperature of the surface ocean.
Enhanced biological productivity in the ocean.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the carrying capacity?

A

A species population size which can be sustained.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are density dependent factors?

A

Limiting factors which can affect population growth e.g availability of food, predators etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the equation used to estimate the biomass of the fish stick at any point in time? (Words)

A

Biomass now = biomass one year ago + growth + birth - mortality - catch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the equation used to estimate the biomass of the fish stick at any point in time? (Symbols)

A

Sn = Sn-1 + G + R - M - C

17
Q

What two conditions must be met for the maximum sustainable yield to be obtained in fishing?

A

The growth rate of resource must be at its highest possible level.
The entire growth of the resource for a given unit of time must be harvested.

18
Q

What are the difficulties with collecting data about fish stocks?

A

Fish populations are mobile and can migrate long distances.
Uneven distribution of fish populations.
Difficult to collect a large enough proportion of the population to be representative.

19
Q

Where does the data come from for commercial catch data?

A

Catch size.
Catch per fishing effort.
Mean fish size.
Mean age.

20
Q

What features make some species more vulnerable to overexploitation?

A

Low fecundity (reproductive rates and number of young).
Slow growth rate.
Reach sexual maturity later.
Natural mortality rate.
Narrow range of tolerance.

21
Q

What do drift nets involve?

A

Nets which hang vertically in the water without being anchored to the bottom.

22
Q

What do purse seine nets involve?

A

FADs are placed in the water to lure fish and surround them with large netting and enclose them.

23
Q

What does bottom trawling involve?

A

Cone shaped nets which are pulled along the seafloor using weights or chains

24
Q

What does dermersal longlining involve?

A

Placing baited hooks along a line at intervals to catch fish.

25
Q

What do crab/lobster pots involve?

A

Cage like gears with openings so they can enter but built in a way so its difficult for them to get out.

26
Q

When are drift nets used and to catch which species?

A

Used to catch pelagic fish and used at night so the fish cant see.

27
Q

When are purse seine nets used and to catch which species?

A

Often the target fish are tuna but can also catch sharks etc. as by catch when FADs are used.

28
Q

When is bottom trawling used and for which species?

A

Used to catch bottom dwelling fish eg shrimp.

29
Q

When are demersal longlines used and to catch which species?

A

Used to catch bottom dwelling fish in the sea depths.

30
Q

When are crab/lobster pots used and to catch which species?

A

Used to catch crabs or lobsters etc.
Also allows unwanted species to escape.

31
Q

What are some of the impacts of the fishing techniques?

A

By-catch.
Ghost fishing from abandoned nets.
Damage to seafloor and habitats.

32
Q

What are pelagic fish?

A

Fish which dont live by the coast or at the bottom of the sea.

33
Q

What is ghost fishing?

A

The capture and death of organisms in lost or discarded fishing gear.

34
Q

What is bycatch?

A

When non target organisms are caught when fishing.

35
Q

What are quotas and how do they work?

A

Catch quotas set limits of the total weight of fish which can be landed.

36
Q

How can fishing equipment be altered to increase the sustainability of fishing?

A

Alter the mesh size.
Mesh design.
Escape panels.
Acoustic deterrent devices.
Turtle exclusion devices.

37
Q

How can the mesh size help with sustainable fishing?

A

If the mesh size is made larger then smaller and unwanted fish will be able to escape.

38
Q

How can the mesh design be altered to increase sustainability?

A

If the mesh direction is diagonal to the direction of the movement allows small fish to escape.

39
Q

What are some fishing restrictions used to increase the sustainability of fishing?

A

No take zones.
Bans on bottom trawling.
Closed seasons.