Question of the day:

• What are some examples of human impacts upon the oceans?

• What are some ways to alleviate these impacts?

Case Study:Depleting Bluefin Tuna Stocks

– Being fished at 4 times the sustainable level

– Economic value places it in danger– Conservation measures protect the species– Overfishing

• Harvesting of fishes faster than they can reproduce

• 30% of worldwide fishes• 80% of commercial fish stocks in US• If overfishing and pollution aren’t curbed,

populations of all harvested seafood species will be gone by 2048

Blue Fin Tuna video clip

•http://www.youtube.com/watch?v=dsbx6dQuRhQ&safe=active

Human Impacts on the Ocean

• Fisheries and aquaculture• Marine shipping• Marine pollution• Coastal development• Offshore mining• Global climate change• In 2008, less than 4% of ocean

remained unaffected by human activities; 41% serious harm

Human Impacts on the Ocean

• Marine Pollution and Deteriorating Habitat– Paradox: ocean provides food but is

used as dumping ground– Pollution increasingly threatens fisheries– 80% of ocean pollution comes from land

activities

Human Impacts on the Ocean

Human Impacts on the Ocean

Overfishing• World Fisheries

– Valuable food resources• 90% of world’s catch is fishes,• 6% is clams, oysters, squid, octopus, and

other mollusks• 3% is crustaceans: lobsters, crabs, shrimp• 1% is marine algae

– World’s Annual Harvest• 1950 - 19 million tons• 2004 - 95 million tons

Overfishing• Problems and Challenges for the Fishing

Industry– No nation has legal claim to open ocean

• Resources are susceptible to overuse and degradation (Tragedy of the Commons)

– Many species have been harvested to the point where their numbers are severely depleted

• Unstable for marine species that rely on them as part of food web

• At least 75% of world’s fish stocks are exploited, overexploited or depleted

– Growing human population requires protein– Technological advances allows efficient catch,

removing all fish from an area– 25% of all is bycatch (unintentionally caught,

then discarded)

What a Scientist Sees

Human impacts past 5 years

• HW check and discussion

Aquaculture Impacts• Aquaculture

– Fish farming: growing of aquatic organisms for human consumption

• Fresh and marine water• HDCs harvest more from open ocean• Developing nations harvest more from

aquaculture– Abundant supply of cheap labor– Limit to harvest is the area available for farming

• Fish farms have dense populations– Lots of polluting waste– Cause net loss of wild fish (raised fish tend to be

carnivorous)

– Ocean ranching: deep-water, off-shore aquaculture

• Doesn’t harm coastline, but less oversight

Aquaculture cage farming

Ocean Dumping• Shipping, Ocean Dumping, Plastic Debris

– Millions of ships dump oily ballast and waste– MARPOL bans marine pollution from shipping

industry• Not well enforced

– Ocean Dumping Ban Act• Cities used to dump sewage into ocean, disease-

causing organisms contaminated shellfish

– Plastic waste• Doesn’t degrade, just breaks up into smaller pieces• Pacific Garbage Patch, 2009, 2x size of Texas• Plastic pieces entangle marine mammals and birds• Filter feeders ingest plastic pieces, carriers of PCBs

Crazy Ocean Dumping Stories

• Wired Science video clip

Plastics and Debris

Great Pacific Garbage Patch Video clip from Wired Science

Coastal development• Coastal Development

– Alters or destroys coastal ecosystems:• Mangroves, salt marshes, sea grass beds,

coral reefs

– Coastal areas overdeveloped, highly polluted, overfished

– Coastal management plans are inadequate

• Biggest problem is human population size• 60% of world’s population lives within150

km (93 mi) of coastline• As much as 75%, by 2025

• Human Impacts on Coral Reefs– 25% of world’s corals are at high risk

• Silt washing downstream from clear-cut forests is smothering reefs

• High salinity from freshwater diversion projects• Overfishing of top predators• Damage by tourists• Pollution from ocean dumping and coastal

pollution• Bleaching = stressed corals expel

zooxanthellae

What a Scientist Sees- Coral Bleaching

Coral Bleaching

• Offshore Extraction of Mineral and Energy Resources– Large deposits of minerals lie under the

sea floor• Manganese nodules -

– mining would adversely affect sea life and market value would not cover expense of mining

– Disputes over deposits under international waters

• Petroleum -– Major source of energy– Major threat to fishing

Manganese deposits

Oil Spills

• Student research and presentations

• Climate Change– Incomplete understanding,

unanticipated effects• There could be a disruption of the ocean

conveyor belt, which transports heat around the globe

• Climate warming could shut down conveyor belt within a decade

– Could cause major cooling in Europe– Major warming in other parts of the world

– Would not sequester CO2 into ocean more CO2 in atmosphere more warming more weakening of belt

Global Climate Change

1. What are some of the harmful environmental effects associated with the fishing industry? With aquaculture?

2. How does the widespread use of plastics contribute to ocean pollution?

3. How might the effect of global climate change on the ocean alter the global climate?

STOP

Addressing Ocean Problems• Learning Objectives:

1. Describe international initiatives that address problems in the global ocean

2. Explain goals associated with correcting ocean problems in the future

Addressing Ocean Problems• Problems are complex and require complex

solutions– UN Convention on the Law of the Sea (UNCLOS) -

1994 - 157 countries have ratified• Protecting ocean resources

– UN fish stocks agreement - 1995• Regulates marine fishing

– Fishery Conservation and Management Act - 1977• Protect essential fish habitat for 600 species• Reduce overfishing, rebuild populations, minimize

bycatch• Fishing quotas, restrictions on fishing gear, limits on

number of fishing boats, closure of fisheries during spawning

Addressing Ocean Problems• Future Actions

– US Commission on Ocean Policy-2004 report

• Create a new ocean policy to improve decision making-

– Consolidate agencies

• Strengthen science and generate information for decision makers

– Need for high quality research

• Enhance ocean education to instill in citizens a stewardship ethic

– Environmental education should be part of the curriculum at all levels, including strong marine component

Addressing Ocean Problems• Future Actions

– Establishment of “no-take” reserves– Substantial reduction of fishing fleet– Remove subsidies of fishing industry– Adopt an ecosystem-based approach to

manage ocean environments• Focus on preserving the health and function of

the entire marine ecosystem• Establish networks of fully protected marine

reserves• Less than 5% of US marine environments have

been protected, with great success

Addressing Ocean Problems

Case Study• The Dead Zone in the Gulf of Mexico

– N and P runoff from Mississippi river• Algae grow rapidly, dead algae sink to

bottom and decompose, deplete water of O2 (hypoxic zone)

– Only anaerobic bacteria thrive there– March to September, worst June-

August– Climate change is making dead zones

worse, even without runoff• Threaten biodiversity and coastal fisheries

Case Study

Global Climate Change

1. Which international treaties aim to protect ocean resources?

2. What are the main goals recommended by the US Comission on Ocean Policy?