Quiz 10 Flashcards
Density dependance in fish population
- also called compensation or depensation
- difficult to measure
- probably a principal reason why fisheries fail
Surplus production
-progeny in excess of replacement
Ugly rumors
- S-R relationshi[s are 2 D
- nature works on averages
- nature wastes
- anthropogenic mortality behaves like natural mortality
Ugly truths
- S-R relationships are not 2D
- nature does not work on averages
- nature does not waste
- anthropogenic sources of mortality do no behave like natural mortality
Growth overfishing
- excessive harvesting of younger individuals in a population
- results in lower mean sizes of fish caught
Recruitment overfishing
-excessive harvesting of the reproductive spawning stock such that there is a decline in reproduction and recruitment
Bycatch
-teh capture of untargeted spp other than whats being targeted
How can gathering of primary data in fisheries be flawed
- inaccurate estimates of catch by observers
- false reporting by fisheries
- failure to include accurate data in estimates
Overcapitalization of fleeets
- driver of overfishing
- nations invest in building up their fishing fleet capacity`
Super trawler
- factory ships
- can fish virtually anywhere
- catch is processed and flash-frozen on board
Types of fisheries used for fishing
- subsistence
- commercial
- recreational
How is sport fishing regulated
- creel limits
- slot limits and other size limits
- closures
How is commercial harvesting regulated
- gear restrictions
- mesh size restrictions
- quotas
- closures
ITQ
-Individual transferrable quota
TAC
-total allowed catch
Why manage a fishery?
- sustainability
- equitability
- optimize production
- ecosystem management
Ecosystem-based approaches
- considering key physical, biological, and ecological factors
- management to conserve entire ecosystem
- considering the behavior of driving forces behind fisheries
Ecopath
-an analytical tool to determine stocks and flows of biomass in an ecosystem that supports fisheries
PPR
- primary production required to support fisheries
- derived from Ecopath
Magnuson fishery conservation and management act of 1976
- extended US territorial boundaries out to 200 miles
- gave US authority sole over most of its continental shelf
- Justification: faliure of international agreements to prevent overfishing
Fisheries conservation zone
-the 200 mile zone created by Magnuson fishery conservation and management act of 1976
Magnuson-Stevens sustainable fisheries act
- provisions to protect aquatic habitat
- new definitions for OY and overfishing
Thermal expansion
-water expands as its heated up
