December 11, 2013
Chapter 12: Sustaining Aquatic Biodiversity
December 11, 2013
Case Study: Lake Victoria and decline of cichlids
http://www.jgi.doe.gov/sequencing/why/twocichlids.jpg
Cichlids: feed
on detritus,
algae,
zooplankton
80% of 500
fish in Lake.
Lost 200
species.
1. Nile perch: large, predatory fish.
Introduced to lake to stimulate export to
Europe.
-Increased poverty and malnutrition by putting
small-scale fisheries and and vendors out of business
-Local forests depleted: Perch needed to be
smoked not sun-dried
December 11, 2013
Case Study: Lake Victoria and decline of cichlids
http://www.jgi.doe.gov/sequencing/why/twocichlids.jpg
2. Algal blooms because of nutrient runoff
from farms, deforested land, untreated
sewage, and declining population of cichlids.
3. Invasion by water hyacinth
-Block sunlight, deprive fish and plankton
of oxygen, reduce diversity of aquatic plants
-Control?
December 11, 2013
Case Study: Lake Victoria and decline of cichlids
http://www.jgi.doe.gov/sequencing/why/twocichlids.jpg
4. Nile perch population is declining: reduced
its own food supply and overfishing
-Allow cichlids population to recover?
December 11, 2013
3 patterns of marine biodiversity:
1.
2.
3.
Greatest marine biodiversity occurs in coral reefs,
estuaries, and deep-ocean floor.
Biodiversity is higher near coasts than in the open
sea because of the greater variety of of producers in
habitats in coastal areas.
Biodiversity is higher in the bottom region of the
ocean than in the surface region because of the
greater variety of habitats and food sources on the
ocean floor.
http://en.wikipedia.org/wiki/File:Coral_reef_in_Ras_Muhammad_nature_park_%28Iolanda_reef%29.jpg
December 11, 2013
Value of Aquatic Biodiversity
Ecological
• est. $21 trillion/year
Economic
• Food source for 3.5 billion
people.
• Antibiotic and anticancer
chemicals
• Pharmaceuticals
Others?
Others?
December 11, 2013
H
Human Impacts on Aquatic Biodiversity I
P
• HIPPO
• Habitat loss and degradation!
> Coral reefs
> Mangrove swamps
> Coastal wetlands
> Rivers
*90% of fish living in ocean
spawn in these areas.
P
O
Why are these
areas under most
intense pressure
from human
activity?
December 11, 2013
Human Impacts on Aquatic Biodiversity
• 20% coral reefs destroyed, 20% damaged
• 15% seagrass beds disappeared
• Dying kelp beds
http://sanctuaries.noaa.gov/about/ecosystems/kelpimpacts.html
http://en.wikipedia.org/wiki/File:Kelp_forest.jpg
December 11, 2013
Human Impacts on Aquatic Biodiversity
Rising sea level
• 10-25 cm in last 100 years
• *global warming
• Destroy more coral reefs, swamp low-lying islands,
cover wetlands
http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/sea-level-rise.gif
http://www.mtc.ca.gov/images/ta01-0209/Sea-Level_Rise.gif
December 11, 2013
Human Impacts on Aquatic Biodiversity
Mangrove forests
• shrimp farming
• timber
• recreation and ecotourism
• flooding
http://earth.jsc.nasa.gov/EarthObservatory/Shrimp_Farms_and_Mangroves,_Gulf_of_Fonseca.htm
http://gallery.usgs.gov/images/01_06_2009/k52Rj77ihc/medium/DSCN0201.JPG
December 11, 2013
Trawler fishing boats
"submerged bulldozers"
• Used to harvest bottom
fish and shellfish
• Each year, disturb 150x
clear cut forest area
http://www.joeshoulak.com/wsj/?cat=39
December 11, 2013
December 11, 2013
Freshwater habitat disruption
*Dams holdback 3-6 times amount that flows in natural
rivers.
*Humans take twice as much water each year from
rivers and lakes
-agriculture
-urban use
http://www.lrp.usace.army.mil/portals/72/siteimages/Recreation/union_citydam.jpg
December 11, 2013
Aquatic Invasive Species
• accidental or deliberate
introduction
• bioinvaders
• cause of about 2/3 fish
extinction in US
(1900-2000)
• Where do they come
from?
> ballast water
> floating plastic
H
I
P
P
O
http://invasions.si.edu/nbic/images/deballast3.jpg
December 11, 2013
Aquatic Invasive Species
• Asian swamp eel
>
>
>
>
dumping of a home
aquarium
eats anything
breathe air (not
affected by waterborne
poisons
can travel across land
into other waters
http://el.erdc.usace.army.mil/ansrp/ANSIS/html/monopterus_albus_asian_swamp_eel.htm
• Purple loosestrife
>
>
ballast water and
import for medicinal
use from Europe
introduced predators to
loosestrife to reduce
population (biological
control)
• Zebra mussel
>
>
>
>
http://www.cdfa.ca.gov/plant/ipc/biocontrol/images/weeds/35pls_inf.jpg
Native distribution in
Russia, spread to
Western Europe, than
in Great Lakes
(probably from ballast
water)
reproduce quickly
kill other mussel
species
clog pipes
http://www.dcr.virginia.gov/natural_heritage/vaisc/images/hp-zebra-mussel.jpg
December 11, 2013
Population Growth and Pollution
2006: 45% of world's population
lived along or near the coastal zone.
• pollution (nitrogen and
phosphorous, run-off)
• recreational use of freshwater
systems
> input of sediment
• toxic pollutatns from industrial
and urban areas
• plastic items
> wildlife ingest, become
entangled in, or are poisoned
by them.
H
I
P
P
O
December 11, 2013
Overfishing and Extinction
H
I
75% of world's commercially
valuable marine fish species are
overfished or fished near their
sustainable limits.
• commercial extinction: no longer
profitable to continue fishing
• modern industrial fishing can
cause 80% depletion of a target
fish species in only 10-15 years.
P
P
O
http://ocean.si.edu/slideshow/world
December 11, 2013
Overfishing and Extinction
Overfishing is usually only a
temporary depletion, as long as
depleted areas are allowed to
recover
• changed industry: fishing with
large fleets (millions of boats),
high profit
• overfishing --> economic and
ecological loss
• Shift from larger fish (tuna,
swordfish) to smaller fish
• bycatch
http://ocean.si.edu/slideshow/world-fisheries-sea-table
http://www.bnl.gov/newsroom/news.php?a=22980
http://ocean.si.edu/ocean-photos/orange-roughy-and-bycatch
December 11, 2013
Overfishing and Extinction
• Fish threatened with biological extinction
> overfishing
> water pollution
> wetland destruction
> excessive removal of freshwater
• 34% marine and 71% of freshwater fish species face
biological extinction within lifetime.
• *Most threatened by human activities with extinction
December 11, 2013
Why is it difficult to protect aquatic biodiversity?
1.
Human ecological footprint is expanding so rapidly,
difficult to monitor the impacts.
2. Much of the damage is not visible to most people
3. Many people incorrectly view the sea as an
inexhaustible resource that can absorb an almost
infinite amount of waste and pollution.
4. Most of world's ocean lies outside the legal
jurisdiction of any country
> *tragedy of the commons
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
National and international laws and treaties
> CITES (Convention on International Trade in
Endangered Species)
> 1979 Global Treaty on Migratory Species
> US Marine Mammal Protection Act of 1973
> US Endangered Species Act of 1973*
> US Whale Conservation and Protection Act of
1976
> 1995 International Convention on Biological
Diversity
*For homework, look up the 2 (not ESA since we
already looked at it) national and international laws
and treaties. Write a paragraph that summarizes the
goals, how it achieves the goals, and its
enforcement. Also include some opinions or
criticisms about the law/treaty.
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
National and international laws and treaties
> Turtles: 6 of 7 species endangered because of
human activity.
– Use of TED (turtle exclusion device) required
for shrimp trawlers (US)
– Economic tools
« Sea turtles worth more alive than dead
(ecotourism v. selling meat, leather, eggs)
« Manatees can help manage water hyacinth
December 11, 2013
Case Study: Commercial Whaling
• Cetaceans
• Easy to kill: large, need to surface
to breath.
• Over-harvesting reduced 8 of 11
species to commercial extinction
• International Whaling Commission
(IWC): mission to regulate whaling
industry by setting quotas
> not enough data to support
quotas
> no enforcement
• 1970: US stopped all whaling and
banned imports of whale products
• Established moratorium on
commercial whaling (government
of countries in IWC)
• Japan, Norway, and Iceland
continue to kill for "scientific
purposes"
> Commercial
> economy and culture
December 11, 2013
Case Study: Commercial Whaling
• Should whaling be allowed?
• Yes:
> Proposed hunting levels too
low to deplete stocks again
> System to monitor and
enforce whaling practices
• No:
> Whales are peaceful,
intelligent, sensitive, social
mammals (ethical
obligation?)
> recovery? Estimation not as
accurate
> opening door for any
commercial whaling lead to
widespread
> worth more alive than dead
(whale watching)
December 11, 2013
*Whales fit typical scenario of species that are very
vulnerable to extinction
-Economically valuable to humans (meat, oil, bones)
-k-selected species (25 years to reach maturity, only
reproduce 2-5 years)
-HUGE: easy to spot
-group together in feeding grounds
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
2.
National and international laws and treaties
Marine Sanctuaries
> International law: country's offshore fishing zone
extends 370 km from shores
– Exclusive economic zones: foreign fishing
vessels can take certain quotas of fish w/in
zones (36% ocean surface, 90% fishstocks)
– high seas: ocean outside jurisdiction
Instead of protecting,
governments promote
overfishing, subsidize
new fishing fleets, failed
to protect water and fish.
*Profit!
http://www.lib.noaa.gov/retiredsites/docaqua/nmai1999.html
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
2.
National and international laws and treaties
Marine Sanctuaries
> Marine protected areas (MPAs)
– 1300 MPA, 200 in US
– partially protected from human activity
– allow dredging, trawler fishing, recreation
> Marine reserves
– fully protected: no extraction and alteration
– 20 nations
– Full protection works, and works fast (with in
2-4 years):
« fish population x2
« fish size grows by 1/3
« fish reproduction x3
« species diversity increases by 1/4
– Benefits fisheries: fish and larvae move out of
reserves
> zoning rules
– establish zones with in an area that allows for
certain activities in areas and requires permits
for others
– Great Barrier Reef Marine park
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
2.
National and international laws and treaties
Marine Sanctuaries
> 0.3% of world's ocean area is in marine reserve
– to increase to 30%, cost $12-14 billion/year
– US: G. W. Bush created Northwestern Hawaiian
Marine National Monument. Protects 360,000
sq. km of federal water around Hawaiian
islands
> Future:
– how big do reserves have to be?
– how many do we need?
– where should they be?
– how can the reserves be connected?
> Opposition to reserves:
– recreation
– fisheries
http://sanctuaries.noaa.gov/sos2006/images/nwhimap.jpg
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
2.
3.
National and international laws and treaties
Marine Sanctuaries
Integrated coastal management
> Community based effort to develop and use
coastal resources more sustainably
> gather scientists, conservationists, local, business
groups, developers, politicians
> *balance of preservation and economic/social
needs
– Short term trade-offs for long-term ecological/
economic benefits
– Used in zoning in Great Barrier Reef Marine
Park
December 11, 2013
Protecting and Sustaining Marine Biodiversity
1.
2.
3.
4.
National and international laws and treaties
Marine Sanctuaries
Integrated coastal management
Revamping US Ocean Policy
> Need for greater protection of US coastal waters
> National policy?
> Ocean research
> centralize fragmented management of oceans
> marine reserves w/corridors
> manage coastal development
> reorient fisheries: sustain ecosystem rather than
catch limits
> program to increase public awareness
December 11, 2013
Managing and Sustaining Marine Fisheries
http://www.noaanews.noaa.gov/stories2008/images/herring1.jpg
http://www.st.nmfs.noaa.gov/Assets/economics/documents/feus/2011/images/total-sales-us-seafood.png
http://www.alaskaseafood.org/sustainability/images/Fisheries-Management-Chart.jpg
December 11, 2013
Managing and Sustaining Marine Fisheries
December 11, 2013
Managing Marine Fisheries by improving estimate of fish
population:
• maximum sustained yield (MSY): projects
maximum # of fish that can be harvested annually w/o
causing population to drop
> difficult because population size hard to determine
– growth rate also difficult to estimate
> can also cause effects in other organisms
• optimum sustained yield (OSY): takes into account
interactions with other species, provide more room for
error
> OSY < MSY
> economic, social, ecological factors
> Greatest benefit for nation
• Multispecies management: takes into account
interactions of species
> manage multiple species under same plan instead
of one at a time
• large marine systems: integrated computer model
to manage multispecies fisheries
•
December 11, 2013
Uncertainty underlies all of these strategies:
• population size difficult to estimate
• can't predict effects of reducing population size
Trend towards precautionary principle: reducing fish
harvests, close overfished areas to allow recover
*wait until more information tells them that they can
take more fish sustainably*
December 11, 2013
Regulating fish harvest: Cooperation
Historically, communities (not government) have
established allotment and enforcement systems to
sustain fisheries, jobs, and communities.
Growth of fishing industry = need for regulation
• replace community management with
comanagement: coastal community and government
work together to manage fisheries
> government sets quotas, seasons, type of fishing
gear
> community allocates and enforces quota among
members
December 11, 2013
Protecting, sustaining, and restoring wetlands
Examples of wetlands:
Coastal wetlands (mangroves, estuaries)
Marshes
Peat Bogs
http://en.wikipedia.org/wiki/File:Mangrove_trees_in_Everglades.JPG
December 11, 2013
Wetland protection in the US
Louisiana has 40% of nation's saltwater marshes. Lost to:
• reduced sediment flow by levees and dams
• global warming and rising sea levels
Wetlands are filled in and destroyed to be used for:
• land for urban development
• land for crops
• rice fields
• reduce disease (mosquitos)
• extract minerals, oil, natural gas
W/loss of wetlands, also lose
• biodiversity
• commercial values: fish, shellfish
• migratory paths of birds
December 11, 2013
Wetland protection in the US
US policy: "Zero net loss" in function and value of
coastal and inland wetlands. But people still want to use
wetland areas. Compromise? Policy?
• mitigation banking: can destroy wetland as equal area
of asme type is created or restored
> Is restoration as good as protection?
– probably not
– not as complex
– not monitored well
• *developers can buy credits from private wetland banks
> credit from restoring wetlands
> $300 million
December 11, 2013
Restoring the Florida Everglades (p. 264-265)
1. What is the Everglades?
2. What factors contributed to the degradation and
destruction of the Everglades? How much was
destroyed?
3. Why was the Kissimmee River altered and what was
its effect?
4. What was the initial solution in 1947 and why did this
not work?
5. Where does all of the freshwater go!?
6. Wha are the goals of CERP?
7. Name 3 shortcomings of CERP
8. How do you see the interplay of politics and
environmental science in this case study?
December 11, 2013
Managing Lakes
*Look at Case Study on great Lakes and invasive
species!
December 11, 2013
Managing River Basins
Disrupted by:
• overfishing
• pollution
• dams
• water
withdrawal for
irrigation
December 11, 2013
Managing River Basins
Dams: Columbia River
Pros:
• provide hydroelectric power
• water for irrigation and urban areas
Cons:
• reduces fish population (especially migratory
fish like salmon: interrupt life cycle)
• Destroy habitat
• reduce flow of sediment and nutrients
December 11, 2013
Managing and Sustaining Freshwater Fisheries
Strategies:
• encourage populations of commercial and sport fish
species (why sport fish?)
• prevent overfishing
• reduce populations of less desirable specie
• How?
> fishing season
> regulate # and size of fish taken (why?)
> build reservoirs and farm ponds
> fertilize nutrient-poor lakes and ponds
> create/protect spawning sites
> manage sediment, aquatic plants, dams
December 11, 2013
Protecting Wild and Scenic Rivers in US
National Wild and Scenic Rivers Act
• protects rivers and river segments w/ scenic,
recreational, geological, wildlife, historical, or cultural
value
> wild rivers: inaccessible, untamed, not permitted
to be widened, straightened dredged, filled, or
dammed
> scenic rivers: accessible in small areas, no dams,
mostly undeveloped
> recreational rivers: readily accessible, some dams
or some development
• *only 0.2% river length included
• 2% free-flowing
• 17%: dams and reservoirs
December 11, 2013