marine fisheries and aquaculture

marine fisheries

long history of exploitation
renewable resource
sustainable levels possible
difficult with modern technology
need to improve management practices
important source of employment

drift gill net

one fishing boat can deploy 65 km of ______ per day
when you add the contribution of all world fleet, there would be around 3.5 million km of ______ (enough to circle the earth 88 times)
over 200 incidental species are caught
UN called for the cessation of all large scale pelagic ______ fishing in international water by the end of 1992
enforcement issues

fishery management

each coastal nation manages the fisheries within its EEZ
wide range of management practices and regulations
difficult to enforce
requires significant amount of information
main goal: determine how much fish is available to harvest - surplus production model, population model

equilibrium fishery

the total annual catch equals the population growth rate for that year
the catch per unit of effort (cpue) is used as an index of the population's biomass

overfishing

removal of a species of fish from a body of water at a rate that the species cannot replenish in time

growth overfishing

fish are caught very young and before they are able to grow optimally, therefore, size, volume, and price of fish reaching the market is reduced

recruitment overfishing

occurs when the mature adult population is depleted to a level where it no longer has the reproductive capacity to replenish itself - there are not enough adults to produce offspring

ecosystem overfishing

occurs when the balance of the ecosystem is altered by overfishing

open access

most important fishery aspect that needs to be solved to address the massive list of marine resources
regiment fisheries reach the equilibrium points where the total income = total costs (net income = 0)
to overcome this situation the number of fishermen needs to be lowered

aquaculture

Aquaculture is breeding, raising, and harvesting fish, shellfish, and aquatic plants
habitat degradation/destruction
high nutrient inputs
coastal infrastructure that generated conflicts
pollution (chemicals, added antibiotics)
catching marine fish to feed cultured fish