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Exploitation of the Seas > Lectures 4-7 > Flashcards

Lectures 4-7 Flashcards

1
Q

Define aquaculture/mariculture

A

cultivating populations of aquatic organisms under controlled conditions.

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2
Q

what is the difference between aqua and mari culture

A

one is in water the other refers specifically to marina aquaculture

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3
Q

on a global scale where doe most aquaculture take place

A

australasia followed by europe and the americas

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4
Q

how much has aquaculture production increased since the 70’s -2006

A

tenfold (0.7 -7 kg per capita)

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5
Q

approximately how many million tonnes per year will be required by 2050 to keep up with global demand?

A

80

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6
Q

how much aquaculture production since 1970 can be accounted for with molluscs

A

70%

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7
Q

how much did crustacean production increase between 1980 and 2010?

A

50 fold

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8
Q

where does aquaculture/mariculture take place?

A

fresh, brackish and marine waters on the continental shelf where the oceans are most productive. most takes place in asia.

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9
Q

what threats do fish farms pose to the marine environment?

A

eutrophication due to concentrated fish sewage. Escape of non-native species and genetically modified organisms. Incubation of local diseases as well as potential evolution of new diseases and parasites in response to antibiotics and preventative drugs. Herbicides which will leak into the surrounding environment and predator control issues which may result in unnecessary deaths of protected species.

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10
Q

what are some of the benefits of aquaculture?

A

increase food security, decrease poverty, increase sustainability of fish stocks.

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11
Q

how many units of fish meal are required to produce 1 unit of fish in an average aquaculture environment?

A

2-5

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12
Q

where does fish for fish meal come from?

A

wild capture fisheries (anchovies, mackerel, herring etc)

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13
Q

potential solution to problems with protein requirements of farmed fish

A

farm herbivorous/ omnivorous fish such as cichlid tilapia or karp which are highly productive and can feed on algae.

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14
Q

where are the majority of ‘farmed’ tuna sourced?

A

Wild stocks which are then transferred to fattening cages and sold on at maximum weight.

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15
Q

where are the 2 main stocks of wild tuna?

A

gulf of mexico and medditeranean therefore 2 stocks, therefore 2 systems of management

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16
Q

what percentage of atlantic bluefin Tuna is absorbed by japan?

A

90%

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17
Q

what is the governing body that aims to set sustainable tuna quotas?

A

ICCAT, International commission for the conservation of Tunas.

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18
Q

what percentage of tuna production is from illegaly caught above quota tuna?

A

35%

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19
Q

feed conversion rate for tuna fattening

A

15/20:1

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20
Q

does sound travel faster in air or water?

A

5x faster in water

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21
Q

what is the structure and measurable factor of a sound wave?

A

pressure wave measured in frequency

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22
Q

what is the difference between high and low frequency sound waves?

A

Low frequency soundwaves travel long distances but produce poor resolution when used in scanning, whereas high frequency sounds have shorter range but produce high resolution scans as the gap between the waves is smaller.

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23
Q

hypotheses regarding wales and low freq sounds?

A

they use them for long distance communications (possibly)

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24
Q

how can sound waves be redirected

A

reflected rarefacted and compressed (depending on physical boundaries it meets and their structures.

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25
Q

what does sound propogation in water depend on ?

A

temperature, PH, salinity. (general chemichal state of the water?

26
Q

7 causes of anthropogenic noise in the oceans?

A

seismic surveys, fisheries, leisure activities, naval/military activity, science, shipping, construction

27
Q

Where are sound frequencies used in seismic surveys concentrated?

A

300Hz but does spill out into higher frequencies.

28
Q

what frequencies do naval sonar operate at?

A

LF 100-500Hz, HF- 2-8KHz

29
Q

What negative conservation effects has naval sonar been linked to

A

Mass strandings of whales and cetaceans found to have developed the bends from rapid decompression.

30
Q

ecological effects of anthropogenic marine noise are…?

A

displacement, altered foraging behaviour, change in sound threshold for that individual (can be temp or perm). increased stress and masking of communications.

31
Q

what do marine species use sound for?

A

find prey and navigate. attract mates. socialising/communicating.

32
Q

problems with calculating acceptable noise levels to minimise ecological effects?

A

PTS/TTS not known for most species and sound propogation is complex and hard to predict.

33
Q

What specific legislations are there regarding acceptable anthropogenic oceanic noise levels?

A

NONE

34
Q

Why are crocodilians traditionally exploited?

A

1800’s harvesting for skin/’leather’. demand dropped in 1820’s, rose again in the 1860’s due to a cow leather ban and then became a fashion his in europe in 1930’s?

35
Q

there are managed croc skin harvesting programs in…

A

USA, zimbabwe, and Papau new guinea but the latter two are not well monitored!

36
Q

What are whales caught and exploited for?

A

spermacetti oil, blubber, meat, baleen (bristles), ambergris, (leisure -sport/tradition), bone, vitamin rich liver!.

37
Q

what legal entity protects whales and controls whaling?

A

International whaling Commission

38
Q

how have whaling laws stood since 1986?

A

zero catch for commercial whaling, special permits for scientific research, and small quota for aboriginal subsistence whaling.

39
Q

How is aboriginal subsistence whaling defined?

A

It is the responsibility of national governments to provide the commission with evidence of the cultural and subsistence needs of their people.

40
Q

critically endangered cetaceans

A

river dolphin, vaquita porpoise

41
Q

endangered cetaceans

A

sei whale, blue whale, fin whale, right whales, 2 spp dolphin

42
Q

why are seas turtles exploited?

A

turtle/tortoiseshell jewellery and accessories

43
Q

what are marine hydrocarbon deposits composed of?

A

small animals which died millenia ago and have been converted under high temperature and pressure have been converted into oil.

44
Q

where are hydrocarbon deposits typically located?

A

continental shelves, trapped beneath impermeable rock by shifting earth plates

45
Q

how are hydrocarbons in the marine environment located ?

A

seismic surveys, using sound waves to map the sea floor by sensing reflections from the sea bed.

46
Q

what happens if an oil deposit is found?

A

test drilling rig, followed by permanent static platforms when a well is established.

47
Q

how is oil stored/ transported from the rigs?

A

large storage and offloading oil tanker vessels ie torrey canyon, prestige

48
Q

where do tankers deliver crude oil?

A

huge oil refineries

49
Q

environmental problems with human oil extraction?

A

frequent minor oil leaks during location and extraction.sometimes huge ie.deep water horizon. oil has a devastation impact on organisms and ecology with long lasting toxic affects if it leeches into the soil or remains in the water. tanker vessels can also crash and spill oil.

50
Q

how can oil spills be located?

A

remote sensing via sattelite, radar surveys, oil reflects a greater proportion of sound waves than water!

51
Q

what else can radar surveys from sattelites track?

A

vessels and icebergs.

52
Q

where was prestige oil spill?

A

off the coast of spain.

53
Q

where did the torrey canyon oil spill effect and what was used to clean it up?

A

cornwall and emulsifying substance sprayed by boats.

54
Q

how can spills be tracked?

A

open source software with wind and current data.

55
Q

what methods are used to clean oil spills?

A

in the sea: booms and skimmers, emulsifiers(airially dispersed), burning. On the coast: scraping it off the surface, pressure hosing back into sea to skim off.

56
Q

long term effects ofthe methods used to remove oil spills?

A

emulsifiers? - break oil into tiny particles so not visible however these have a toxic effect and are more easily taken in by organisms,so long term negative effects.
burning? -transfers pollutant from sea borne to air borne.
scraping? -oil still leeches into sand killing inverts.
hosing? - moves the problem, can obliterate and flora and fauna which may have been present, ruining ecology

57
Q

how does oil effect sea turtles?

A

stops their salt glands functioning resulting in osmotic imbalance and death.

58
Q

general effects on wildlife?

A

modifies feeding behaviour, impairs breathing, failure to react to predators, displacement from habitats, alters ecology of species and habitats.

59
Q

what are specific effects of oil on birds?

A

effects ability to thermoregulate by clumping feathers - over preening- high energy expenditure - failure to forage - death.

60
Q

physiological effects of oil?

A

direct lethal toxicity - endocrine system, immune system. PAH’s from oil are carcinogenic. Down stream effects on progeny (mutant turtles). Bioaccumulation of toxic compounds in food chain.

Exploitation of the Seas (1 decks)

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