Transcript AP Environmental Science

Ch 13
Sustaining Aquatic
Biodiversity
Overview of Aquatic Biodiversity
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World oceans cover 71% of the planet’s surface
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63% of known fish species exist in marine systems
37% live in freshwater systems
Humans have only explored 5% of the earth’s
global ocean
Ecological and economical benefits could result
from further scientific study of poorly understood
marine and freshwater systems.
Life As We Know It- 9min
Overview of Aquatic Biodiversity
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2003 – Pew Commission found U.S. coastal
waters were in trouble and laws protecting them
needed reforming
Commissions recommendations:
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Double the federal $ for ocean research
Base fisheries management on preserving aquatic
ecosystems and habitats rather than catch limits
Set up a systems of marine reserves
The Magnuson-Stevens Act- passed in 2007
which mandates annual catch limits and
accountability measures and calls for
international cooperation.
Overview of Aquatic Biodiversity
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Coral reefs, estuaries, and the ocean bottom
contain the greatest marine biodiversity
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Greater variety of producers, habitats, food sources and
nurseries
Biodiversity is higher near coastlines than open ocean
Benthic (bottom) regions have greater biodiversity than
surface regions
Lowest diversity is the middle region of the open
ocean
6% of our total protein and 20% of our animal
protein comes from marine fish and shellfish—
potentially renewable resource.
Human Impacts on Aquatic
Biodiversity
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Greatest threat is loss and
degradation of habitats
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1/2 of world’s coastal wetlands
lost during the last century
25% of world’s coral reefs
severely damaged, mostly by
humans
1/3 of world’s original
mangrove forests have
disappeared, mostly due to
clearing for development
Bottom habitats are being
degraded and destroyed by
dredging and trawler boat
activity
Factory encroaching on wetlands
Bleached Brain Coral
Human Impacts on Aquatic
Biodiversity
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3/4 of the world’s 200 commercially valuable fish
are either overfished or fished to their estimated
sustainable yield.
 Overfishing leads to commercial extinction
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Modern fishing methods could cause 80% depletion
in only 10-15 years
Large fish in many commercially valuable
species are becoming scarce
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Study showed in the last 45 yrs the abundance of
large open ocean fish like tuna and bottom-dwelling
fish like cod have fallen 90%
Human Impacts on Aquatic
Biodiversity
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After large species are disrupted, the fishing
industry works its way down the food chain to
smaller fish disrupting the food chain further
One-third of the annual fish catch is thrown
overboard dead or dying as bycatch (nontarget
species)
Human Impacts on Aquatic
Biodiversity
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1200 marine species have become extinct in the
past several hundred years
Fish are more threatened with extinction by
human activity than any other animal
37% of the known freshwater fish in the U.S and
20% of the 10,000 freshwater fish in the world
are threatened with extinction or are already
extinct (UN Food and Agriculture Organization)
Blue (Prionace glauca) and Mako shark fins at a shark finning camp, Magdalena Bay, Baja
California, Mexico.
Human Impacts on Aquatic
Biodiversity
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Deliberate or accidental
introduction of nonnative species
into coastal waterways, wetlands,
and lakes cost the U.S. about $16
million per hour
Purple loosestrife was imported
into the U.S. in the 1880’s as an
ornamental plant.
 Released in ballast water
 Single plant can produce 2.5
million seeds/yr
 Native plants cannot compete
 State have begun to introduce a
weevil species and a leaf-eating
beetle. Will they become pests?
Protecting and Sustaining Marine
Biodiversity
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Protecting marine biodiversity is difficult because
 Much of the damage in not visible
 Resources of the ocean viewed as
inexhaustible
 Most of the world’s oceans lies outside of legal
jurisdictions so it is subject to over exploitation
--tragedy
Protecting and Sustaining Marine
Biodiversity
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Protecting marine
biodiversity is the same
as protecting terrestrial
biodiversity; identifying
and protecting
threatened and
endangered species and
their habitats
A California Sea Lion entangled in a fishing net that is slowly killing it.
Case Studies: Commercial Fishing and
Sea Turtles
Major
commercial
fishing methods.
Modern methods
enable increasing
harvest of
decreasing
populations.
Protecting and Sustaining Marine
Biodiversity
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3 of 8 major sea turtle species
are endangered and the rest are
threatened
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Degradation of beach habitat
where they lay eggs, legal and
illegal taking of eggs
Increased use as a food, medical
ingredient, jewelry, and leather
Unintentionally captured and
drowned by commercial
fisherman – as many as
40,000/yr
 Turtle exclusion devices have
saved 1000’s of turtles from
shrimp trawlers.
Turtle ejected here
Shrimp end
up here
Case Study: Whaling
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Commercial Whaling
(Cetaceans)
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Easy to kill because of
their large size and need
to come to surface to
breathe
Mass slaughter increased
with the use of radar and
airplane to locate the
whales
1.5 million whales killed
between 1925 and 1975
8 of 11 major species
became commercially
extinct and the blue
whale to the point of
biological extinction
Protecting and Sustaining Marine
Biodiversity
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The International Whaling Commission (IWC) was
established in 1946 to regulate the whaling
industry by setting annual quotas
Did not work
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IWC quotas were based on inadequate data or ignored
by whaling countries
IWC did not have power of enforcement
In 1970, The U.S. stopped all whaling and
banned the import of all whale products
In 1986, the IWC has imposed a moratorium on
whaling. Whales killed dropped from 42,480 in
1970 to 1,200 in 2004
Protecting and Sustaining Marine
Biodiversity
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Norway and Japan continue to hunt certain species and Iceland
resumed hunting in 2002
Japan, Norway, Iceland, Russia, and a number of small tropical
islands are working towards overthrowing the IWC whaling ban
 A traditional part of the economies and culture of some
countries
 Believe ban is based on emotion not updated scientific
estimates of whale populations
 Eskimos still allowed to whale
Atlantic
white-sided
dolphin
Common
dolphin
Harbor
porpoise
Killer
whale
Bottlenose
dolphin
Beluga
whale
Cuvier's
beaked
whale
False killer
whale
Pilot
whale
Narwhal
Pygmy
sperm
whale
0
0
5
10
Sperm
whale
Baird's
beaked
whale
10
20
30
Squid
15
40
Odontocetes (Toothed Whales)
50
20
60
25
70
80
30m
90
100ft
Protecting and Sustaining Marine
Biodiversity
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The UN Law of the Sea
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All coastal nations have sovereignty over the waters 12
miles offshore
Jurisdiction over their Exclusive Economic Zone, which
stretches 200 miles offshore
The rest is high seas
Control over 36% of the ocean and 90% of the
fish stock yet the oceans are still over fished
World Conservation Union (IUCN) since 1986, has
helped develop a global system of Marine
Protected Areas (MPAs)
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Protected from all or most of human activities
1,700 existing MPAs protect about 0.2% of ocean area
Protecting and Sustaining Marine
Biodiversity
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Marine Reserves - no
take or fully protected
MPAs.
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No extraction or alteration
of living or nonliving
resources is allowed
Australia has the largest
Results?-- Fish
populations double, fish
sizes grow by one-third,
fish reproduction triples,
and species diversity
grows by almost onefourth in 2-4 years
Less than 0.01% of the
world’s ocean and 50
square miles in U.S. are in
Protecting and Sustaining Marine
Biodiversity
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Integrated coastal management is
community-based efforts to develop and
use coastal resources more sustainably
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Develop workable, cost effective, adaptable
solutions that preserve biodiversity and still
meet economic and social needs
Zone areas to include fully protected marine
reserves and other zones where different levels
of human activities are permitted
90 coastal counties in the U.S. are working to
establish integrated coastal management
zones with 20 of them fully implemented
Managing and Sustaining The
World’s Marine Fisheries
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World commercial fishing has been
managed by maximum sustained
yield (MSY) -the maximum number of
fish that can be harvested from a fish
stock without causing a population
drop.
Hasn’t worked
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Fish stock difficult to measure and based on
unreliable and underreported catch
Populations of other target and other non-target
fish species and marine organisms also affected
Quotas are difficult to enforce
Managing and Sustaining The World’s
Marine Fisheries
**Optimum sustained yield (OSY) -takes
into account interactions with other
species to provide more room for error
 Multi-species management takes into
account the competitive and predator-prey
relationships of a number of interacting
species
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Proposed Catch Share Policy
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2009 Obama stated his
administration’s commitment to
creating comprehensive protective
measure for our national fisheries and
other oceanic wildlife.
NOAA Catch Share Policy has been
drafted
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Uses several fishery management
strategies to allocate portions of the
fishery catch to individuals,
cooperatives, communities, etc.
Rebuild and sustain fisheries
Must stop fishing when their quota is
reached
Prevents “race for the fish”
Protecting, Sustaining, and Restoring
Wetlands
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Coastal and inland wetland
are areas of tremendous
aquatic biodiversity
Federal permits required to
fill in 3 or more acres of
wetlands
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Cut average wetland loss by
80% between 1969 and 2002
8% of remaining wetland are under federal control
Mitigation banking allows destroying existing
wetlands in exchange for creation of artificial
wetlands in another area.
 50% of created wetlands fail or do not replace
the ecological functions of the natural wetlands
Protecting, Sustaining, and Restoring
Lakes and Rivers
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Great Lakes are the world’s largest body of fresh
water
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They have been invaded by 162 nonnative species since
1920. Most have arrive in the bilge water of ships
 Sea lampreys
 Zebra mussels
 Asian carp – to reach the lakes soon
Nonnative species are their greatest
threat.
Protecting, Sustaining, and Restoring
Lakes and Rivers
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Rivers and streams
provide important
ecological and economic
services
 Can be disrupted by
over fishing,
pollution, dams, and
water withdrawal for
irrigation
 Lakes much more
vulnerable than
rivers. Why?
Case Study: Columbia River
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Columbia River
 World’s largest hydroelectric
power system
 Irrigation for agricultural land
 Water source for major municipal
areas
 Salmon blocked from migrating
upstream to lay their eggs due to
dams disrupting rivers
 Salmon needs trees along the
river to keep water cool enough
for the eggs to survive and to
keep silt from covering them
Solutions
Rebuilding Salmon Populations
Building upstream hatcheries
Releasing juvenile salmon from hatcheries to
underpopulated streams
Releasing extra water from dams to wash juvenile salmon
downstream
Building fish ladders so adult salmon can bypass dams
during upstream migration
Using trucks and barges to transport salmon around
dams
Reducing silt runoff from logging roads above salmon
spawning streams
Banning dams from some stream areas
Protecting, Sustaining, and Restoring
Lakes and Rivers
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Salmon Ranching has taken the place of wild
salmon spawning
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Salmon eggs and young are raised in hatcheries and
released into the wildcompetition
Reduces the genetic diversity of the wild salmon
Environmental stress after fish release
Human capture
Fish change form
Salmon
processing
plant
Fish enter rivers
and head for
spawning areas
To hatchery
In the fall spawning salmon
deposit eggs in gravel nests and die
Modified
Life
Cycle
Grow to maturity
in Pacific Ocean
in 1-2 years
Eggs are taken from adult
females and fertilized with
sperm “milked” from males
Fry hatch in the spring...
Normal
Life
Cycle
Eggs and young are
cared for in the hatchery
And grow in the stream
for 1-2 years
Grow to smolt
and enter the ocean...
Fingerlings migrate downstream
Fingerlings
are released into river
Protecting, Sustaining, and Restoring
Lakes and Rivers
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1968, National Wild and Scenic Rivers Actprotects rivers and river segments with
outstanding scenic, recreational, geological,
wildlife, historical or cultural value
 Wild rivers may not be widened, straightened,
dammed, filled, or dredged.
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Swimming, camping, nonmotorized boating, sport
hunting, and fishing are permitted
Scenic rivers are not dammed, mostly
undeveloped, accessible by road in some areas
and of great scenic value
Recreational rivers are readily accessible by
roads and have some development along their
shores
Natural Capital
Ecological Services of Rivers
•Deliver nutrients to sea to help sustain coastal
fisheries
•Deposit silt that maintains details
•Purify water
•Renew and renourish wetlands
•Provide habitats for wildlife