Wild Capture Fisheries

Question 1

What are the stats in regards to human dependence on fish?

Answer 1

1 in 5 people in the world depend on fish as a primary source of protein
In 2008 global seafood consumption was 143 million tonnes with 47% from aquaculture
60% of fish consumption is by the developing world
Fish also provide a protein source indirectly by livestock fed with fish

Question 2

What are the stats in regards to capture fisheries?

Answer 2

Seafood from wild stocks is insufficient to meet growing demand
>70% of the worlds fish stocks are either fully exploited or depleted
Stocks of many of worlds great fisheries now at <10% of unexploited levels
As shallow water stocks are depleted, the global fishing fleet is seeking fish from deeper water

Question 3

Describe the collapse of the Peruvian anchovy

Answer 3

• pre-1950 fish harvested only for human consumption
  annual catch - 86,000 tonnes
• 1953 first fish meal plants developed
• Within 9 years Peru was no. 1 fishing nation
• At peak 1700 purse seiners (large wall of netting) exploited 7 month fishing season
• 1970 fisheries scientists issued a warning that the estimated sustainable yield was 9.5 million tonnes
• 1970 government allowed 12.4 million tonnes of fishing
• 1971 - 10.5 million tonnes
• 1972 - total collapse of fishery by El Nino event
• 20 years to recover

Question 4

Stats on Scotland’s fishing activities

Answer 4

• 42spp., half of them exploited
• salmon, sea trout etc.
• Angling contributed 112 million to Scottish Economy in 2003 of which 52 million came from salmon anglers
• 90% decline in commercial catches taken since 1970
• Fewer salmon now taken by commercial salmon fisheries than retained by rod sport fisherman

Question 5

Why is over fishing becoming an increasing problem?

Answer 5

Almost nowhere less than 1,500m deep that is not exploited
Technology improvements - Diesel engines, sonar location, GPS, larger more efficient nets, driftnets
Industry is now twice as large as necessary

Question 6

How is pollution depleting fish populations?

Answer 6

Anoxic dead zones around mouths of rivers such as Severn and Mississippi
Toxic plankton blooms

Question 7

How is habitat destruction a threat to sustainability?

Answer 7

In many places seabed ploughed bare by repeated trawling - destroys rich communities of corals, sea fans and sponges
Coastal development - destruction of sea grass beds, mangrove forests

Question 8

How is climate change a threat to sustainability?

Answer 8

Warmer water - less food, affects breeding, reduces oxygen water content

Question 9

What are the major threats to freshwater fish?

Answer 9

Habitat degradation 
- dams
- river regulation
- pollution
- spread of parasites and diseases
Harvest
- over fishing
- poaching
Stocking
- release of domesticated fish
- release of non-native fish