Ch. 11 Sustaining Aquatic Biodiversity
• 11-1 What are the Major Threats to Aquatic Biodiversity?
* The greatest marine biodiversity occurs in coral reefs, estuaries, and the
deep-ocean floor.
* It is higher near coasts than in the open sea (because of producer variety)
* It is also higher on the bottom region of the ocean due to greater variety of
habitats and food.
• Human Activities are Destroying & Degrading Aquatic Habitats
• Some of the greatest loss is due to HIPPCO
•Habitat loss and degradation – trawling (dragging nets across ocean bottom),
destroy coral reefs, bottom dwelling habitats & kill several ocean bottom
creatures.
Before trawling
After trawling
*Freshwater habitats are
destroyed or drastically
changed by Dams &
Excessive water withdrawal!
• Invasive Species are Degrading Aquatic Biodiversity
* 84% of the world’s coastal waters are being colonized by invasive
species. (2008 Nature Conservancy study)
* Bioinvaders are blamed for about 2/3 of fish extinctions in the U.S.
between 1900 and 2000. (They cost the country $14 million per hour)
*Invasive water Hyacinths,
supported by nutrient runoff in
Kenya’s Lake Victoria.
Plastic litter caught on seal!
• Population Growth and Pollution can reduce Aquatic Biodiversity
* By 2020, 80% of the world’s people will be living along or near the coasts
(U.N. Environment Programme)
* Increased population means increased aquatic habitat destruction and
pollution.
• Climate Change is a Growing Threat
* Biggest problem comes from rising sea levels; they have risen 4-8 inches in
the last 100 years and are predicted to rise another (0.6-1.9 feet) and perhaps
as high as (3.2 – 5.2 feet) between 2050 and 2100!
• Overfishing and Extinction: Gone Fishing, Fish Gone
• Fishprint – the area of ocean needed to sustain the consumption of an average
person, nation, or the world. 2006 Fishprint of Nations, stated, all nations together
are overfishing the world’s global oceans by an unsustainable 157%!
Commercial Fish
Harvesting
Methods
• 11-2 How Can We Protect & Sustain Marine Biodiversity?
• Laws and Treaties have protected some Endangered and Threatened Species
• Problems:
* Human ecological footprints and fishprints are expanding
* Much of the damage in water is not visible to most people
* Many people incorrectly view the seas as an inexhaustible resource
• Efforts:
* 1975 Convention on International Trade in Endangered Species (CITES)
* 1979 Global Treaty on Migratory Species
* U.S. Marine Mammal Protection Act of 1972
* U.S. Endangered Species Act of 1973
* U.S. Whale Conservation and Protection Act of 1976
* 1995 International Convention on Biological Diversity
• Economic Incentives Can be used to Sustain Aquatic Biodiversity
• There can be economic rewards in restoring and sustaining aquatic systems.
•Ex. Reconciliation Ecology; according 2004 WWF study; sea turtles are
worth more alive than dead (used for meat, leather and eggs). Tourism
brings in three times more money than the sale of turtles does.
•Japan and Norway kill up to 2,000 whales a year
by calling it “scientific purposes”
• Whale Wars (Animal Planet) Show volunteers
fight to stop these ships from whaling.
• Marine Sanctuaries Protect Ecosystems & Species
* A countries offshore fishing zone extends to 200 miles from its shores;
Foreign vessels can only take certain quotas of fish from those zones called
exclusive economic zones.
* High Seas = anything beyond jurisdiction (Not protected very Well)
* MPA (marine protected area) – areas of ocean partially protected from human
activity. (4000 worldwide & 200 in U.S.
- They still allow dredging, trawling and other activities.
• Establishing a Global Network of Marine Reserves: An Ecosystem Approach to
Marine Sustainability
* Goal = to protect and sustain whole marine ecosystems for current & future
generations instead of focusing on protecting individual species.
* By creating Marine Reserves – fully protected areas; some of which
already exist, this would allow for recovery and flourishing aquatic
ecosystems. (Most work quickly, within 2-4 years)
* Cost of a global network of marine reserves = 12-14 billion a year;
which would create over 1 million jobs according WWF 2004. (this is
the same amount governments currently spend on encouraging
overfishing.)
• 11-3 How Should We Manage & Sustain Marine Fisheries?
• Estimating and Monitoring Fishery Populations is the 1st Step:
* Old and not very successful approach was maximum sustained yield idea to
project maximum # of fish that can be harvested. (Difficult to estimate)
* Others: optimum sustained yield approach – accounts interactions among
species. Multispecies management – a # of interactions (competition/predators
* Best: Precautionary Principle for management
• Some Communities Cooperate to Regulate Fish Harvests
* Norway’s Lofoten fishery, one of the largest cod fisheries, has been selfmanaged without the gov for over 100 years.
* Comanagement – Gov set quotas per communities have grown recently.
• Government Subsidies can Encourage Overfishing
* According to a 2006 study, 30-34 billion per year is given by gov to fishers to
keep business running.
* Marine scientists believe 10-14 billion of this is spent to encourage overfishing
and expansion of the companies!
• Some Countries Use the Marketplace to Control Overfishing
* ITR’s (individual transfer rights) have been set up to control access to
fisheries. Gov gives each fishing vessel owner a specified % of total allowed catch
for a given year. These can then be bought, sold or leased as private property.
• Consumers Choices Can Help
Partial List of Good & Bad Fish to eat according to www.edf.org
(Environmental Defense Fund)
Eco-OK
Eco-Worst
Eco-Best
Clams (wild)
Chilean sea bass
Char, Arctic (farmed)
Cod, Pacific (trawl)
Grouper
Crab, Dungeness
Crab, snow/tanner
Orange roughy
Mussels
Flounder/sole (Pacific)
Rockfish (trawl)
Oysters (farmed)
Lobster, American/Maine Salmon, farmed/Atlantic
Sablefish (Alaska, Canada)
Scallops, sea (U.S.,
Shark
Salmon, wild (Alaska)
Canada)
Swordfish (imported)
Sardines, Pacific (U.S.)
Shrimp (U.S. wild)
Tilefish (Gulf of
Shrimp, pink (Oregon)
Squid
Mexico/South Atlantic)
Trout, rainbow (farmed)
Tuna, bigeye/yellowfin
Tuna, albacore (U.S., Canada) Tilapia (Latin America)
Tuna, canned light
(imported longline)
All Eco-Best Fish »
All Eco-OK Fish »
Tuna, bluefin
All Eco-Worst Fish »
Pocket Version of all: (pdf)
http://www.edf.org/documents/1980_pocket_seafood_selector.pdf
• 11-4 How should we Protect & Sustain Wetlands?
• Coastal and Inland Wetlands are Disappearing around the World
* Since 1900 the U.S. has lost almost ½ of them; other countries, even more!
* New Zealand has lost 92% and Italy 95%
* Lost by draining, filling in, covering over for: crops, expanding cities, and
roads. Also extracting minerals, oils, gas has destroyed wetlands.
• We can Preserve & Restore Wetlands
* Zoning Laws – steer development away from wetlands; permit required.
* Mitigation Banking – policy that allows destruction of wetlands as long as an
equal area of the same type is created or restored.
Problem = created wetlands are hard to make successfully.
Green Career = Wetlands Restoration Expert
* Can They Restore the Florida Everglades?
• 11-5 How Can We Protect and Sustain Freshwater Lakes, Rivers & Fisheries?
• Freshwater Ecosystems are under Major Threats
* HIPPCO – to blame!
* Example: Lake Michigan Invasive Zebra Mussels cost US and Canada
roughly $16,000 per hour to maintain!
• Managing River Basins is Complex &
Controversial
* Example: Columbia River, runs
through southwest Canada and Northwest U.S.,
has 119 dams, some 19 generate hydroelectric
power. Benefits many, but destroys the salmon
population.
• We can Protect Freshwater
Ecosystems by Protecting
Watersheds ( Land areas that deliver
water to major rivers, lakes, etc…)
• 11-6 What Should be our Priorities for Sustaining Biodiversity & Ecosystem
Services?
• Priorities:
• Complete the mapping of the World’s terrestrial and aquatic biodiversity.
• Keep intact the world’s remaining old-growth forests and cease logging them.
• Identify and preserve the world’s terrestrial and aquatic biodiversity hotspots and areas
where deteriorating ecosystem services threaten people and other life forms.
• Protect & restore the world’s lakes and river systems.
• Carry out ecological restoration projects worldwide.
• Find ways to make conservation financially rewarding for people who live in or near
terrestrial and aquatic reserves. (Create Partnerships)
By treating the oceans with more respect and by using them
more wisely, we can obtain more from these life-supporting
waters while also maintaining healthy and diverse marine
ecosystems. Brian Halweil