L12-Fisheries,history,uses,footprint,challenges, intro to science Flashcards
fishery traps?
set up by indigenous people to funnel fish
What does shifting baselines?
people alive now don’t realise how big fish used to be
Which fish have been lost?
large fish
How has catch changed with tech advancement?
It has not changed catch has flatlined
we are catching fewer fish despite working much harder
Why is fish so important as food source? What makes them ideal?
lots of people depend on them
fish require less feed for same mass of meat
fish have a lower carbon footprint
Why are we going to need much more meat?
rising prosperity
as people become richer they eat more meat
How much harder is it to catch fish?
10x as hard
down to 10% of fish
What has changed with how we fish?
we now fish further away more south and deeper
What is human impact of overfishing?
somali pirates
How does industrial fisheries effect local fishers?
negatively can fish far more fish far more easily
How often do fisheries crash?
60 per 5 years(once a month)
How do we manage fisheries?
fisheries science
massive industry outside of australia
How does a population without fishing work?
lots of stock,lots of eggs
high competition,low recruitment
How does population with fishing work?
fewer stock, fewer eggs
low competition, high recruitment
belived that you can take fish from pop without reduceing population over time
What is stock?
number of fish
What are Core principles of fisheries science?
- A stock of known size
- Recruitment is density-dependent, competition is strong
- Allee effects are weak
Which line is sustainible catch
black line
What happens with decreased pop?
reduced competition
What happens to recruitment succes with higher fish mortality?
What are the key phases of the best case senerio for fishier science?
- Assess the size of the stock, its natural mortality and density dependence
- Determine the sustainable yield
- Set the total allowable catch
- Monitor the catch
How much fish can you fish if natural mortality is high?
lots more because fish would die anyway
What is a stock assesment?
• Determine the abundance and size structure of current population
What is Standing spawner biomass?
Biomass of the reproductive fish
