Lectures 13-14 Fisheries Flashcards
what are the Core principles of fisheries science
A stock of known size
Recruitment is density-dependent, competition is strong
Allee effects are weak
What do you need to asses in a fishery
size of the stock, its natural mortality and density
dependence
What are the steps in the best case for fisheries management?
- Assess the size of the stock, its natural mortality and density dependence
- Determine the sustainable yield
- Set the total allowable catch
- Monitor the catch
What does the Biological reference point B mean?
B = Sustainable Biomass
What does B < B threshold mean?
The stock is overfished
What does F < F threshold mean
Overfishing is not occuring
What does the Biological reference point F mean?
F = Fishing mortality
What does Fmsy mean?
fishing mortality rate at the level that would produce maximum sustainable yield from a stock that has a size of Bmsy
What does Bmsy mean?
stock size that can produce maximum sustainable yield when it is finished at a level equal to Fmsy
What does B threshold mean?
stock size threhold, the threhold below which a stock is overfished
What does F threshold mean?
fishing mortality threhold, the fishing mortality rate that causes a stock to fall below its stock size threshold
What does F max mean?
Fishing mortality rate that achieves maximum yield per recuit
What does F% mean?
Fishing mortality rate that reduces the spawning stock per recuit to a given percentage of the maximum spawning potential in the absence of fishing
What is Steepness?
an estimate of density dependence
What does a Steepness = 1 mean?
if there is some fraction of the stock left, recruitment is 100% equivalent to a virgin stock
