chapter 12: sustaining aquatic biodiversity · 1. greatest marine biodiversity occurs in coral...

December 11, 2013

Chapter 12: Sustaining Aquatic Biodiversity

December 11, 2013

Cichlids: feed on detritus, algae, zooplankton

80% of 500 fish in Lake.

Lost 200 species.

http://www.jgi.doe.gov/sequencing/why/twocichlids.jpg

Case Study: Lake Victoria and decline of cichlids

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

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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?

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4. Nile perch population is declining: reduced its own food supply and overfishing

-Allow cichlids population to recover?

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3 patterns of marine biodiversity:

1. Greatest marine biodiversity occurs in coral reefs, estuaries, and deep-ocean floor.

2. Biodiversity is higher near coasts than in the open sea because of the greater variety of of producers in habitats in coastal areas.

3. 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

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Value of Aquatic Biodiversity

Ecological Economic

• est. $21 trillion/year • Food source for 3.5 billion people.

• Antibiotic and anticancer chemicals

• Pharmaceuticals

Others?

Others?

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Why are these areas under most intense pressure from human activity?

Human Impacts on Aquatic Biodiversity

• HIPPO• Habitat loss and degradation!

> Coral reefs> Mangrove swamps> Coastal wetlands> Rivers

*90% of fish living in ocean spawn in these areas.

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• 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

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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

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Mangrove forests• shrimp farming• timber• recreation and ecotourism• flooding

http://gallery.usgs.gov/images/01_06_2009/k52Rj77ihc/medium/DSCN0201.JPG

http://earth.jsc.nasa.gov/EarthObservatory/Shrimp_Farms_and_Mangroves,_Gulf_of_Fonseca.htm

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Trawler fishing boats

http://www.joeshoulak.com/wsj/?cat=39

"submerged bulldozers"• Used to harvest bottom

fish and shellfish• Each year, disturb 150x

clear cut forest area

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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

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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

http://invasions.si.edu/nbic/images/deballast3.jpg

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Aquatic Invasive Species

http://el.erdc.usace.army.mil/ansrp/ANSIS/html/monopterus_albus_asian_swamp_eel.htm

http://www.cdfa.ca.gov/plant/ipc/biocontrol/images/weeds/35pls_inf.jpg

http://www.dcr.virginia.gov/natural_heritage/vaisc/images/hp-zebra-mussel.jpg

• Asian swamp eel> dumping of a home

aquarium> eats anything> breathe air (not

affected by waterborne poisons

> can travel across land into other waters

• Purple loosestrife> ballast water and

import for medicinal use from Europe

> introduced predators to loosestrife to reduce population (biological control)

• Zebra mussel> Native distribution in

Russia, spread to Western Europe, than in Great Lakes (probably from ballast water)

> reproduce quickly> kill other mussel

species> clog pipes

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Population Growth and Pollution H

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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.

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Overfishing and Extinction

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.

http://ocean.si.edu/slideshow/world-fisheries-sea-table

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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

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• 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

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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 people3. 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

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*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.

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

Protecting and Sustaining Marine Biodiversity

December 11, 2013

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


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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

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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)

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*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

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1. National and international laws and treaties2. 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


http://www.lib.noaa.gov/retiredsites/docaqua/nmai1999.html

Instead of protecting, governments promote overfishing, subsidize new fishing fleets, failed to protect water and fish.

*Profit!

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> 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


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> 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

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1. National and international laws and treaties2. Marine Sanctuaries3. 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


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1. National and international laws and treaties2. Marine Sanctuaries3. Integrated coastal management4. 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


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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

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Managing and Sustaining Marine Fisheries

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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•

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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*

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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

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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

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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

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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

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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 CERP8. How do you see the interplay of politics and

environmental science in this case study?

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Managing Lakes

*Look at Case Study on great Lakes and invasive species!

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Managing River Basins

Disrupted by:• overfishing• pollution• dams• water

withdrawal for irrigation

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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

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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

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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

chapter 12: sustaining aquatic biodiversity · 1. greatest marine biodiversity occurs in coral...

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