#29 Fisheries

Question 1

how many fish in Australia vs. how many do we commercially use

Answer 1

have around 5000 species

only 200 are caught for food

Question 2

how do we track fish?

what are they good for

Answer 2

mark recapture - for long distances

acoustic telemetry - for fish that stay in the same environments, fine scale movements

otoliths: fish ear bones - can tell the age and the history of the fish

Question 3

has the annual global yeild of wild-caught fish substanitally changed since the 1990s?

Answer 3

No

Question 4

why did the global yeild of fish caught increase from the 1950s?

Answer 4

due to industrialisation of fishing - new better ways to catch fish such as big boats, freezers etc.

Question 5

are fish exploited globally?

Answer 5

yes around 75%

Question 6

where is australia on the scale of fish catch?

Answer 6

60th - very low fish catch

Question 7

how big is australias fishing zone

Answer 7

third biggest in the world

Question 8

are our waters productive?

Answer 8

no we dont have major upwelling zones

Question 9

where is most productive in aus?

Answer 9

southern waters

Question 10

do we have a high diversity of fish?

Answer 10

yes

our fish are expensive hence we catch less for the same money

Question 11

how is Australian fishing regulated?

Answer 11

managed by Australian fisheries management
well regulated
good practices and sustainable fishing

they are managed by:

• effort controls (gear type restrictions, seasonal closures)
• Output controls (quotas, size limits, bag limits)
• Habitat protection zones (marine parks, nursery grounds, vulnerable populations)
• Stocks are managed for sustainability- catch levels are set to keep population levels steady and to minimise broader impacts on the ecosystem

Question 12

how many fish are overfished in australia

Answer 12

only 3

Question 13

what is a management failure of fish in australia?

Answer 13

southern blue fin tuna
- worth lots of money
travel down to SA via the leeuwin current
are caught and raised in the ocean, fed with anchovies
sold for lots of money
stocks of the fish are at around 4% of the population remaining
critically endangered

Question 14

what happens from illegal fishing?

Answer 14

leave ghost nets in the ocean and animals get caught and die

Question 15

what has damaged the habitat from fishing?

Answer 15

trawling has modified more seafloor than we have cleared land on the earth
by catch is also an issue

Question 16

has aquaculture increased?

Answer 16

yes it has increased over time

Question 17

what are the benefits of aquaculture?

what are the drawbacks?

Answer 17

PROS

• reduce pressure on natural population
• no by-catch
• quality control
• and can produce on demand

CONS

• disease can spread
• may need to take out of the natural population
• may need to feed them more fish / not worth it!
• infrastructure can affect the surrounding areas

Question 18

for aquaculture what are the Top five in terms of production value:

Answer 18

Top five in terms of production value:
• Salmonids
• Tuna
• Pearl oysters
• Edible oysters
• Prawns