Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Environmental science > Fishing > Flashcards

Fishing Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

marine productivity relies on…

A

nutrient availability + variations in light levels

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

what is the difference between the aphotic and the photic layer?

A

ap: light doesn’t penetrate, no photo.
ph: light penetrates, photo.

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

some nutrients are ________ factors on biological _______ i.e. phosphates

A

limiting, productivity

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

define upwellings

A

where colder and more nutrient rich H2O come to the surface and increase biological productivity

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

name the 2 places where upwellings occur

A

continental margins + open ocean

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

what is a continental margin upwelling?

A

wind blows parallel to coastline, pushes coastal surface H2O out to sea

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

define thermal stratification

A

warm H2O less dense so floats on cooler H2O

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

place these in order of low to high productivity:

upwellings, open ocean, coastal areas

A

open ocean, coastal area, upwellings

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

describe the productivity in the open ocean

A
  1. low primary productivity cus of stratification (nutrients remains at depth)
  2. death of planktonic organisms sink to sea bed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the productivity in coastal areas

A
  1. shallow H2O = more light = more photo

2. nutrient runoff from land/rivers

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

describe the productivity of upwellings

A
  1. seamounts change elevation and push H2O to surface

2. storms cause nutrients to distribute

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

what is the difference between pelagic and demersal trawling?

A

pelagic: towing of nets in surface H2O
demersal: weighted nets dragged along sea floor

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

advantages of pelagic trawling

A
  1. can be quite selective (single species shoals)

2. fast + efficient as catch large volumes

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

disadvantages of pelagic trawling

A

bycatch of porpoises, dolphins, seabirds etc.

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

advantages of demersal trawling

A

fast/efficient as catch large volumes (make more money)

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

disadvantages of demersal trawling

A
  1. destroys seafloor habitats i.e. corals/seagrass

2. bycatch high as demersal fish in mixed species shoals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is purse seining?

A

large wall of netting to encircle fish then gathered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

advantages of purse seining

A
  1. no contact with seabed
  2. more species selective
  3. efficient as can catch large shoals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

disadvantages of purse seining

A
  1. bycatch of vulnerable species i.e. sharks/turtles

2. accidental catch of juvenile fish below catch size (thrown back dead/dying)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is drift netting?

A

long nets suspended vertically in H2O (pelagic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

advantages of drift netting

A
  1. cost effective
  2. nets placed by low powered vessels (fuel efficient)
  3. large amount of fish in 1 catch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

disadvantages of drift netting

A

lots of bycatch as its non-selective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is longlining?

A

weighted line of baited hooks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

advantages of longlining

A
  1. no contact with seabed

2. quicker harvesting times (less compression = better quality fish)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

disadvantages of longlining

A
  1. used for pelagic = seabirds caught on hooks i.e. albatross
  2. not very selective, bycatch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are shellfish traps?

A

baited traps that sit on the seabed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

advantages of shellfish traps

A
  1. fewer environmental impacts

2. another opening allows for the release of crustaceans below catch size

28
Q

disadvantages of shellfish traps

A

ghost fishing = shellfish trapped

29
Q

name the 6 impacts of fishing

A
  1. pop. decline
  2. bycatch
  3. ghost fishing
  4. habitat damage
  5. food web impacts
  6. changed age structure
30
Q

describe pop. decline

A

deliberate exploitation of a species

31
Q

effect of pop. decline?

A
  1. effects K species the most as have fewer young etc. (i.e. Orange Roughy + sharks)
  2. catching before sexually matured = no chance to breed
32
Q

how to reduce pop. decline? (5)

A
  • no take zones
  • fishing quotas
  • minimum size of fish caught
  • closed seasons
  • square mesh panels in trawl nets (allow small fish to escape)
33
Q

what is bycatch?

A

any catch that is unwanted. 2 types:

  1. catch of non-target species
  2. catch of target species that are too small to be legally landed/sold
34
Q

what is the effect of bycatch?

A
  1. many bycatch dead/injured won’t survive
  2. reduces biodiversity
  3. impacts food webs
35
Q

how to reduce bycatch? (4 ways)

A
  1. turtle excluder devices/escape panels
  2. acoustic deterrent devices
  3. leaving longlining nets for 15 mins not an hour
  4. change J hooks to circle hooks
36
Q

what is ghost fishing?

A

lost/discarded fishing gear (deliberate or storms)

37
Q

what are the effects of ghost fishing?

A
  1. traps/kills
  2. smother corals
  3. spread parasites
  4. juvenile fish hide = get trapped
38
Q

how to reduce ghost fishing?

A
  1. use biodegradable nets

2. radio tracked equipment

39
Q

what are the effects of habitat damage?

A
  1. seabed damage
  2. coral damage
  3. loss of seagrass meadows (loss of nursery grounds + roots no longer bind sand)
40
Q

how to reduce habitat damage?

A

ban/reduce methods that damage habitats i.e. demersal trawling

41
Q

describe the food web impact

A

reducing any species will have an impact on the interspecies relationships

42
Q

effect of food web impacts?

A
  1. bycatch reduces predators
  2. competitors could be common
  3. fishing/bycatch could reduce pop. of prey i.e. turtles eat jellyfish so increase bycatch of turtles = increase jellies
43
Q

describe the effect on age structure

A

if haven’t reached sexual maturity, hasn’t bred = cannot replenish the pop. (no breeding pop.)

44
Q

describe factory fishing and its effects

A

as fish pop. decrease ships travel further

  • use large amounts of fuel
  • waste effluent deoxygenates H2O = dead zones
45
Q

name the 8 ways to reduce environmental impacts of fishing

A
  1. catch quotas
  2. restricted fishing effort
  3. net design
  4. no take zones
  5. minimum catch size
  6. maximum catch size
  7. captive rearing/release
  8. biodegradable/radio tracked nets
46
Q

what are catch quotas?

A
  1. upper limit on total no./mass of a species that can be caught + legally sold
  2. works best in single species shoals
47
Q

what is restricted fishing effort?

A

limits the size of fishing boats/power of their engines/ no. of days out fishing

48
Q

what is minimum size of individuals caught?

A
  1. banning capture of small fish

2. allows them to grow/reproduce = replenish pop.

49
Q

what is maximum catch size? + example

A
  1. protecting large species
  2. allows for surviving pop. of breeding adults
    - female lobsters around scotland not caught if shell longer than 145 mm
50
Q

what is captive breeding and release?

A
  • eggs/larvae raised in optimum conditions = increase survival
  • released to boost wild pop.
51
Q

what is an issue with captive breeding/release?

A

may not be resistant to local diseases

52
Q

give an example of captive breeding and release

A

lobster hatchery in Cornwall (fishing pressure decreased pop.)

53
Q

what are no take zones?

A
  1. provide safe breeding area

2. lots off offspring leds to fish migrating out of NTZ to areas which can be fished

54
Q

what are closed seasons?

A

ban on fishing during that time of year = allows fish to breed/grow

55
Q

give 3 different types of net design that reduces bycatch

A
  1. excluder devices
  2. mest size set (allows fish below quota to escape)
  3. square mesh panels (can’t close under pressure) = small fish escape
56
Q

give 3 different ways to reduce bycatch NOT TO DO WITH THE NET

A
  1. dolphin pingers/acoustic deterrent
  2. streamer lines
  3. J hooks to Circle hooks
  4. line weighting for pelagic longline
57
Q

define the Maximum sustainable yield for a fish pop.

A

the greatest biomass that can be removed from pop. each year without pop. suffering long term decline

58
Q

fishing rate should not exceed…

A

birth, growth and mortality rate

59
Q

give 2 examples of fish that have been exploited about the MSY

A
  1. orange roughy (k selected species)

2. atlantic cod (catchable size age 2 but reach maturity age 4)

60
Q

name the 4 pieces of data you get from fishing catches

A
  1. catch size
  2. catch per unit fishing effort
  3. mean fish size
  4. mean age
61
Q

why is catch size not good to measure biomass/pop.?

A

better fishing technology maintains catches as pop. declines i.e. better sonar

62
Q

Catch per unit fishing effort: harder to maintain catches…

A

pop. decreasing

63
Q

how can mean fish size see if there’s overfishing?

A

reducing mean fish size = caught faster than reproduction

64
Q

how can mean age of fish see if there’s overfishing?

A

age declining = not allowed to reach maturity/breed

65
Q

collecting data on __________ fish egg/larvae pop. predicts no. of young likely to reach _________

A

planktonic, adulthood/maturity

Environmental science (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions