How Can We Help to Sustain
Aquatic Biodiversity?
We can help to sustain
aquatic biodiversity by
establishing protected
sanctuaries, managing
coastal development,
reducing water pollution, and
preventing overfishing.
Impacts on Aquatic Ecosystems
• Destroyed or degraded by human
activities
• Coastal habitats disappearing 2-10
times faster than tropical forest
• Rising sea levels will destroy coral
reefs and some low islands
• Ocean floor degradation 150 times
larger than area clear-cut annually
Impacts on Aquatic Ecosystems
• Freshwater habitat disruption
– Dams
– Water withdrawals from rivers
• Likely extinction
– 34% marine fish species
– 71% freshwater species
– Greater than any other group of species
Major commercial fishing methods
Fish farming
in cage
Trawler
fishing
Spotter airplane
Sonar
Purse-seine fishing
Drift-net fishing
Long line fishing
Float Buoy
lines with
hooks
Deep sea
aquaculture cage
Fish caught
by gills
Overfishing
•
•
•
•
Fishery
Fishprint
157% overfishing
90% of large open-ocean fishes have
disappeared since 1950
Area of ocean bottom before a trawler net scraped it like a gigantic plow.
The same area after the trawler scraped the ocean bottom. According to marine biologist
Ellie Norse, “Bottom trawling is probably the largest human-caused disturbance to the
biosphere.” Trawler fishers disagree and claim that the ocean bottom life recovers after
trawling.
Why Is Protection of Marine
Biodiversity So Difficult?
• Human aquatic ecological footprint
expanding
• Not visible to most people
• Viewed as an inexhaustible resource
• Most ocean areas outside jurisdiction
of a country
Solutions for Marine
Ecosystems
• Protect endangered and threatened
species
• Establish protected marine
sanctuaries
• Protect existing coastal wetlands
http://www.seafoodwatch.org/cr/cr_seafood
watch/content/media/MBA_SeafoodWatch_
NortheastGuide.pdf
Solutions
Managing Fisheries
Fishery Regulations
Bycatch
Set catch limits well below the
maximum sustainable yield
Use wide-meshed nets to
allow escape of smaller fish
Improve monitoring and
enforcement of regulations
Use net escape devices for
seabirds and sea turtles
Economic Approaches
Ban throwing edible and
marketable fish back into
the sea
Sharply reduce or eliminate
fishing subsidies
Charge fees for harvesting fish
and shellfish from publicly
owned offshore waters
Aquaculture
Certify sustainable fisheries
Control pollution more
strictly
Protect Areas
Restrict coastal locations
for fish farms
Establish no-fishing areas
Depend more on
herbivorous fish species
Establish more marine
protected areas
Nonnative Invasions
Rely more on integrated
coastal management
Kill organisms in ship
ballast water
Consumer Information
Label sustainably harvested
fish
Filter organisms from ship
ballast water
Publicize overfished and
threatened species
Dump ballast water far at
sea and replace with
deep-sea water