Quiz 9 Flashcards
Eggs per Recruit
-estimates total, potential, lifetime egg production of females
VPA
- Virtual Population Analysis
- a retrospective analysis of the cohorts past abundance
- based on catch statistics
Age-based cohort analysis
-approximates results of the VPA without have to iterate to determine value of F
Yield per recruit model
- keeps track of fish growth and total biomass
- also keeps track of pop size, natural mortality, fishing mortality
Why do fisheries managers use the yield per recuit model
- find the size at which fish enter fishery
- gives the amnt of fishing effort to produce max harvests possible
stresses to fish habitat
- Pollution
- Erosion and sediment loading
- water alteration
- introduced spp
- habitat loss
Pragmatists stocking
-waters should be stocked and managed for the best use of that env
Purists stocking
- maintain/restore natural communities
- averse to introducing non-native spp
Why stock fish
- provide more constant access to fish
- increase fish availability
- manage exotic spp
Types of stocking
- introduction
- enhancement
- restoration
Introduction stocking
-putting spp into waters where they do not naturally exist
Enhancement stockin
- ancillary stocking of spp already present
- can be done to maintain a population
- may be done to add fish under harvestable size for future harvestniing
Restoratioin stocking
-increase pop of overexploited/endangered spp
Things to consider before stocking
- How fish will be stocked (how many? methods of stocking)
- what life stage should be stocked
- day/night considerations
Types of aquaculture
- Extensive (minimal inputs)
- Intensive (high conc of fish)
- Polvculture (mixed production
