Sustaining Aquatic BiodiversityCh. 11, part 1
Biodiversity is highest at: Coral reefs, estuaries, and deep
ocean Near coast since more producers
there At bottom since more food and
habitats
Threats to Aquatic Biodiversity
HIPPCO
H = habitat loss & degradation Mostly in coral reefs and
mangroves used by humans
Damage done by trawling
51% of freshwater species threatened with extinction - the most of any group
I - invasive species 84% of coastal
waters invaded Causes 2/3 of
all fish extinctions
Cost USA ~$14 million/year
Often arrive in ballast waterWater
hyacinth in Lake Victoria
P = population growth By 2020 - 80% of world’s people
will live in coastal cities
Lebanon
Rio de Janeiro
P = pollution Just 4% of world’s oceans
unaffected by pollution Most pollution comes from
land activities Pesticides/fertilizers Plastics Oil
C = climate change Causes sea levels to rise
CO2 “sinks” coral reefs, swamps, wetlandsStore CO2 – out of air
Puts coastal cities underwater
O = overfishing Industrialized fishing
depletes populations quickly
Fishprint - area of ocean needed to sustain our fish consumption Currently at 157% Commercial
extinction - no longer profitable to fish since so few left
Bycatch
Fig. 11-7, p. 256
Fish farming in cage
Spotter airplaneTrawler fishing
Sonar Purse-seine fishing
Long line fishing
lines with hooks
Deep sea aquaculture cage
Drift-net fishing
Float Buoy
Fish caught by gills
Stepped Art
The numbers 35% of marine species 71% of freshwater species May go extinct in our lifetime The MOST AFFECTED GROUP of
all species by humans
Dolphin and whale slaughter by Japan
What we can do to help Laws and treaties
Difficult to enforce Most of ocean is not owned by
anyone - tragedy of the commons Economic Incentives - tourism
Long term gain vs. short term profit
Some laws/treaties you should know
CITES - 1975 - trade in endangered species Global Treaty on Migratory Species - 1979 US Marine Mammal Protection Act - 1972 US Endangered Species Act - 1973 US Whale Conservation and Protection Act
- 1976 International Convention on Biological
Diversity - 1995
Who owns the seas? A country owns from its coast to
200 miles out Beyond is the high seas -
international laws and treaties apply here - but who enforces them?
Marine Sanctuaries & Marine Protected Areas (MPAs)
4000 worldwide; 200 in US waters
Offer only partial protection Most still allow dredging,
trawler fishing, drilling, etc CA is leading
Most extensive network of MPAs with most restrictions
The Ecosystem Approach Establish marine reserves all over, especially
coastal areas They work! - in 2-4 years see marked
improvement Increase tourism Help fishing industry
Only .1% of ocean is protected (so we have reserved 99.9% for us)
Costs $12-14 billion/year to make reserves
What can you do? Purchase only sustainably
harvested seafood (WalMart) Support businesses that develop
and use resources sustainably Ecotourism NO Shell shops
thanks
Fisheries Management Step 1: figure out what we have out there! Step 2: switch from old model - Max.
sustained yield - to new model - optimum sustained yield (take species interactions into account)
Step 3: don’t forget the Precautionary Principle
What’s actually happening1. Comanagement - local
communities regulate coastal fishing, government regulates offshore
2. Government subsidies - gov’t (i.e. taxes) support fisheries to keep them in business; encourage expansion (uh…)
3. Individual transfer rights (ITRs) Gov’t gives each vessel of % of the total allowable catch
for the year; companies can trade with each other Problems:
Fishing co. “owns” waters, but public still responsible for cleaning up messes
Harder for small operations to compete Too many ITRs given out - so still overfishing
Successes 1995, Alaskan halibut, fishing season went from 2 days to
260
End part 1
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