1. Ocean Structure and Biodiversity
Marine Diversity
Ocean Structure and Biodiversity

2. Oceans cover most of the Earth’s surface
The oceans influence global climate, team with biodiversity, facilitate transportation and commerce, and provide resources for us
They cover 71% of Earth’s surface and contain 97% of Earth’s surface water
Oceans influence the atmosphere, lithosphere, and biosphere

3. The oceans contain more than water
Ocean water is 96.5% water
Plus, ions of dissolved salts
Evaporation removes pure water and leaves a higher concentration of salt
Nutrients (nitrogen and phosphorus)
Dissolved gas
Oxygen is added by plants, bacteria, and atmospheric diffusion

4. Ocean water is vertically structured
Temperature declines with depth
Heavier (colder saltier) water sinks
Light (warmer and less salty) water remains near the surface
Temperatures are more stable than land temperatures
Water’s high heat capacity
It takes much more heat to warm water than air
Oceans regulate the earth’s climate
They absorb and release heat
Ocean’s surface circulation

5. Ocean water flows horizontally in currents
Currents are continuous, directed movements of ocean water generated by the forces acting upon it and they carry nutrients, heat and gasses.
Surface currents are driven by wind
Deep water currents are driven by density differences, heating and cooling, gravity, and wind
Pole-moving currents are warm water currents that move from the equator toward the north or south pole

6. Major Currents

7. Surface winds and heating create vertical currents
Upwelling = winds blow away from the coast and draws the vertical flow of cold, deep, nutrient rich water towards the surface
High primary productivity and lucrative fisheries
Downwellings = winds blow and push warm water toward the coast; colder, more dense water sinks

8. Salinity The ocean is approximately 3-4% saline
30-40 parts per trillion (ppt)
1/1,000,000,000,000
30 to 40 ng / 1 L
Saline indicates the presence of ions including both mono- and polyatomic
Chloride, sodium, sulfate, magnesium, calcium, potassium and bicarbonate

9. Global Salinity

10. Fishing Practices & Regulations
Here fishy, fishy, fishy!

11. Economic Importance of Aquatic Ecosystems
The economic importance of aquatic diversity is the estimate of the value of their ecological services which is $21 trillion a year.
At least 3.5 billion people depend on the seas for their primary source of food; this number could double to 7 billion in 2025.

12. Driftnets for schools of herring, sardines, mackerel, sharks
Longline fishing for tuna and swordfish
Trawling for pelagic fish and groundfish

13. Trawling Bottom-trawling destroys communities
Likened to clear-cutting and strip mining

14. Fishing has industrialized
Factory fishing = highly industrialized, huge vessels use powerful technologies to capture fish in huge volumes
Even process and freeze their catches while at sea

15. Fishing practices kill nontarget animals
By-catch = the accidental capture of animals
Driftnetting drowns dolphins, turtles, and seals
Fish die from air exposure on deck
Banned or restricted by many nations
Longline fishing kills turtles, sharks, and albatrosses
300,000 seabirds die each year

16. Emptying the oceans
We are placing unprecedented pressure on marine resources
Half the world’s marine fish populations are fully exploited
25% of fish population are overexploited and heading to extinction
Total fisheries catch leveled off after 1998, despite increased fishing effort
It is predicted that populations of all ocean species we fish for today will collapse by the year 2048

17. We have long overfished
People began depleting sea life centuries ago
Some species hunted to extinction: Steller’s sea cow, Atlantic gray whale, Caribbean monk seal
Overharvesting of Chesapeake Bay oyster beds led to the collapse of its fishery, eutrophication, and hypoxia
Decreased sea turtle populations causes overgrowth of sea grass and can cause sea grass wasting disease

18. The total global fisheries catch has increased

19. Industrialized fishing depletes populations
Catch rates drop precipitously with industrialized fishing
90% of large-bodied fish and sharks are eliminated within 10 years
Populations stabilize at 10% of their former levels
Marine communities may have been very different before industrial fishing
Removing animals at higher trophic levels allows prey to proliferate and change communities

20. Modern fishing fleets deplete marine life rapidly
Grand Banks cod have been fished for centuries
Catches more than doubled with immense industrial trawlers
Record-high catches lasted only 10 years

21. Oceans today contain only one-tenth of the large-bodied animals they once did

22. Several factors mask declines
Industrialized fishing has depleted stocks, global catch has remained stable for the past 20 years
Fishing fleets travel longer distances to reach less-fished portions of the ocean
Fleets spend more time fishing and have been setting out more nets and lines, increasing effort to catch the same number of fish
Improved technologies: faster ships, sonar mapping, satellite navigation, thermal sensing, aerial spotting
Data supplied to international monitoring agencies may be false

23. We are “fishing down the food chain”
Figures on total global catch do not relate the species, age, and size of fish harvested
As fishing increases, the size and age of fish caught decline
10-year-old cod, once common, are now rare
As species become too rare to fish, fleets target other species
Shifting from large, desirable species to smaller, less desirable ones
Entails catching species at lower trophic levels

24. Consumer choices influence fishing practices
Buy ecolabeled seafood
Dolphin-safe tuna
Consumers don’t know how their seafood was caught
Nonprofit organizations have devised guides for consumers
Best choices: farmed catfish and caviar, sardines, Canadian snow crab
Avoid: Atlantic cod, wild-caught caviar, sharks, farmed salmon

25. Central Case: collapse of the cod fisheries
No fish has more impact on human civilization than the Atlantic cod
Eastern Canadians and U.S. fishermen have fished for cod for centuries
Large ships and technology have destroyed the cod fishery
Even protected stocks are not recovering

26. Cod are groundfish They live or feed along the bottom
Halibut, pollock, flounder
Cod eat small fish and invertebrates
They grow to cm long and can live 20 years
Inhabit cool waters on both sides of the Atlantic
There are 24 stocks (populations) of cod

27. To Protect and Serve
We can protect and sustain marine biodiversity by using laws, international treaties, and education.
First identify and protect species that are endangered and/or threatened.
Clean up aquatic environments

28. Why is it so hard?
1. Our human footprint is so large and is growing exponentially;
2. Damage to the ocean is not usually visible to the naked eye;
3. People view the ocean as an in-exhaustable resource;
4. The ocean is outside the legal jurisdiction of any one country.

29. We can protect areas in the ocean
Marine protected areas (MPAs) = established along the coastlines of developed countries
Still allow fishing or other extractive activities
Marine reserves = areas where fishing is prohibited (less than 0.3% of the ocean)
Leave ecosystems intact, without human interference
Improve fisheries, because young fish will disperse into surrounding areas

30. Reserves work for both fish and fisheries
Found that reserves do work as win-win solutions
Overall benefits included…
Boosting fish biomass
Boosting total catch
Increasing fish size
Benefits inside reserve boundaries included…
Rapid and long-term increases in marine organisms and decrease mortality and habitat destruction

31. How should reserves be designed?
20-50% of the ocean should be protected in no-take reserves
How large?
How many?
Where?
Involving fishers is crucial fisheries in coming with these answers

32. Areas outside reserves also benefit
Benefits included…
A “spillover effect” when individuals of protected species spread outside reserves
Larvae of species protected within reserves “seed the seas” outside reserves
Improved fishing and ecotourism

33. Marine Management
There are a number of ways to manage marine fisheries more sustainably and protect marine biodiversity.
A country has jurisdiction over the ocean up to 200 miles from it’s coast.
Rather than protecting the marine environment, countries tend to promote fishing.

34. Integrated Coastal Management
Integrated Coastal Management (ICM) is an idea or management policy based on a community approach.
Private sector as well as the public sector work together to identify problems and share the burden of restoration or management.

35. Managing Fisheries Fishery Regulations: Economic Approach:
set catch limits well beyond maximum sustainable yield
improve monitoring and enforcement
Economic Approach:
reduce or eliminate subsidies
charge fees for harvesting fish and shellfish from public areas
certify sustainable fisheries

36. More Management Protected Areas: Consumer Education:
establish “no-fishing” zones
establish more reserves
rely on integrated coastal management
Consumer Education:
label sustainably harvested fish
educate about overfished and endangered species

37. Management (cont.) Bycatch: Aquaculture: Non-native Invasions:
streamline fishing techniques and tools
Aquaculture:
restrict coastal locations for fish farms
control pollution (CWA)
depend on herbivorous fish species
Non-native Invasions:
kill organisms in ship ballast water, filter ballast water or dump in open sea

38. Legislation: Each group will discuss the event and the impact
International Convention of the Regulation of Whaling
US ban on whaling and importation of whale products
US Marine Mammel Protection Act
US Endangered Species Act
Convention on International Trade in Endangered Species (CITES)
Global Treaty on Migratory Species

39. Revamping Ocean Policy
Two recent studies called for an overhaul of U.S. ocean policy and management.
Develop unified national policy.
Double federal budget for ocean research.
Centralize the National Oceans Agency.
Set up network of marine reserves.
Reorient fisheries management towards ecosystem function.
Increase public awareness.

40. MANAGING AND SUSTAINING MARINE FISHERIES
There are a number of ways to manage marine fisheries more sustainably and protect marine biodiversity.
Some fishing communities regulate fish harvests on their own and others work with the government to regulate them.
Modern fisheries have weakened the ability of many coastal communities to regulate their own fisheries.

41. Solutions Managing Fisheries Fishery Regulations
Set catch limits well below the maximum sustainable yield
Improve monitoring and enforcement of regulations
Bycatch
Use wide-meshed nets to allow escape of smaller fish
Use net escape devices for sea birds and sea turtles
Ban throwing edible and marketable fish back into the sea
Economic Approaches
Sharply reduce or eliminate fishing subsidies
Charge fees for harvesting fish and shellfish from publicly owned offshore waters
Certify sustainable fisheries
Aquaculture
Restrict coastal locations for fish farms
Control pollution more strictly
Depend more on herbivorous fish species
Protected Areas
Establish no-fishing areas
Establish more marine protected areas
Rely more on integrated coastal management
Figure 12.7
Solutions: ways to manage fisheries more sustainably and protect marine biodiversity. QUESTION: Which four of these solutions do you think are the most important?
Nonnative Invasions
Kill organisms in ship ballast water
Filter organisms from ship ballast water
Dump ballast water far at sea and replace with deep-sea water
Consumer Information
Label sustainably harvested fish
Publicize overfished and threatened species
Fig. 12-7, p. 261

42. The graph to the right shows the decline in the catch of groundfish (such as cod, haddock, and flounder) from Georges Bank from 1965 to This decline in the fish harvest resulted in the closure of large portions of the fishery.
Identify the five-year period during which the greatest rate of decline in the fish harvest took place. For that five-year period, calculate the rate of decline in the fish harvest, in metric tons per year. Show clearly how you determined your answer.

43. Choose any TWO commercial fishing practices from the list below
Choose any TWO commercial fishing practices from the list below. For each of your choices, describe the practice and explain the role it plays in the depletion of marine organisms.
 Bottom trawling
Long-line fishing
Using drift nets/gill nets/purse seines
Using sonar
 Identify one international regulation or United States federal law that applies to the harvesting of marine food resources and explain how that regulation or law helps to manage marine species.
 The oceans of the world are often referred to as a commons. Give an example of one other such commons, explain how human activities affect that commons, and suggest one practical method for managing that commons.

44. Using the APES Rubric
Let’s score your response