ess 4.3

==4.3.1==

food products from aquatic ecosystems

algae consumption

• green algae
• brown algae
• red algae

fish - most popular aquatic food

• the global fish consumption/production rate continues to increase
  • used for human consumption
  • animal/pet feed
  • fertelizers
  • gelatin
• why is fish demand so high?
  • human pop. growth
  • health benefits
  • growth in income, people can afford fish

shellfish:

• molluuscs:
  • invertebret
  • ex:
  • gastropods
    • sea snails
  • bivalves
    • clams
    • oyster
    • scallops
  • Cephalopods
    • octopus
    • squid

other animals:

• Crustacean: have exoskeleton:
  • ex:
  • lobsters
  • shrimp
• Echinoderms
  • invertebret w/ symmetry
  • ex: strafish
• reptiles
• Amphibians
• aquatic mammals

seal hunting

• used by natives
• used for meat, clothes, fur
• threatened habitats
• Canada has attempted to regulate seal hunting:
  • setting limits to number of hunted seals

4.3.2

capture fisheries

• fishery growth driven by:
  • human pop & increased demand for fish
  • technological developments

nets:

• oftentimes nets will capture animals that are not meant to be in
• trawler nets: used to catch fish by dragging a net along a seabed
• purse siene nets: used to catch schools of a species, the fish are surrounded by the net, which is then closed like a draw string purse to trap the fish.
• drift nets: hung vertically in the water, used to get sardines, swordfish, tuna

fish yeild

• fish stocks are only renewable if removal rate doesnt exceed growth rate

overfishing - why its common

• property rights - no one owns fish
• zero sum gain

4.3.3

reduction in fishing

• reducing boat size
• restricting gear
• reducing number of boats
• restricting fishing times
• marine protected areas

cod fisheries- case studies

• newfoundland
  • technology allows for more fishing
  • they overfished, resulting in tons of job loss
• iceland
  • gov’t took action to prevent overfishing
  • protecting territorial waters
  • restrictions
  • exclusion zones

4.3.3

• aquaculture: farming of aquatic organisms
  • Open based systems:
  • farm organisms in thier natural ecosystem
  • semi closed systems:
  • take water from ecosystem and bring them into tanks on land
  • enviornment impacts:
  • habitat loss
  • increase in organic sediments
  • increase in avaliable nutrients
  • use of medicine/hormones
  • disease
• managing env. impact of fish farms:
  • removal of dead fish
  • reducing waste of uneaten feed
  • aerate water

sustainable yield

• natural income

• can measure in biomass or number of individuals

• SY= (births + immigration) - (deaths & emigration)

• yield: total growth from year to year

  

• bycatch: marine creatures lost/killed due to fishing practices

  • dolphins
  • turtles
  • sharks

whaling

• innuit culture:
  • part of thier culture
  • northern canada
  • a hunting culture
  • not for profit
  • used every part of the whale
  • “connection w/ enviornment”
  • acceptance by canadian people'
• japan culture:
  • commerical
  • cultural - traditional
  • not using whole animal
  • meat sold illegally
  • left IWC