Environmental Issues & Problems
ENV 150
Quiz # 1
Guillaume Mauger
Today:
Quiz Review
Discuss research paper
Topic: Fisheries Collapse
Reminder:
Due THURS: Service-Learning Agreement
REMEMBER TO TURN IN YOUR 2nd FORM TO PATTI !!!
Quiz # 1
about the research paper:
There are four assignments that lead up
to the final paper
1. Paper proposal
Done
2. Annotated bibliography
Due 11/5
3. Rough draft
Due 11/19
4. Draft for Peer Review - in class: 12/10
(… Final Draft Due on 12/15)
research paper topics…
note: Thursday’
Thursday’s class will be held in the
library.
Fisheries Collapse
videos:
http://www.youtube.com/watch?v=nkUEYbCSTnk
http://www.shiftingbaselines.org/videos/index.html
Reading Scientific Papers
Reading Scientific Papers
What is a scientific paper?
What is a scientific paper?
… what about “peer review”?
… what about “peer review”?
How are they written / organized?
… scientific writing is not a particularly
creative writing style: it’s concise,
predictable, detailed, and strives for
clarity in meaning.
example abstract:
Reading Scientific Papers
Reading Scientific Papers
General questions to ask:
• What is the goal of the research?
Big Picture
• Why is this an important question?
• How do they manipulate / interpret the data?
• What is the conclusion? Does it make sense?
Does it fit with your prior conception?
Fisheries Collapse
A comment from a parent left at the Birch
Aquarium at Scripps:
Marine Biodiversity, patterns
1. Greatest diversity exists in coral reefs,
estuaries, and on ocean floor.
2. Biodiversity is greatest near coasts
"I brought my children to the aquarium so
they could see the things I saw at the
seashore as a child."
3. Biodiversity is greatest near ocean
floor than on the surface.
Specifics
• Where does their data come from?
Marine Biodiversity, value
Marine Biodiversity, losses
Fisheries Collapse:
Estimated value of marine ecosystem
services:
$21 trillion / yr
Source: Meyers and Worm, Nature, 2003
Marine Biodiversity, losses
Fisheries Collapse:
Marine Biodiversity, losses
Fisheries Collapse:
Facing Extinction within your lifetime:
90% of Large Predatory Fish
populations have disappeared
Source: Meyers and Worm, Nature, 2003
34% of known marine fish species, and
71% of known freshwater fish species
Source: IUCN Red List
Source: Meyers and Worm, Nature, 2003
Marine Biodiversity, losses
Fisheries Collapse:
Species
Pacific herring
Atlantic herring
Atlantic cod
South African Pilchard
Haddock
Peruvian anchovy
Polar cod
Cape hake
Silver hake
Greater yellow croaker
Atlantic redfish
Cape horse mackerel
Chub mackerel
Blue whiting
South American pilchard
Alaska pollock
N Pacific hake
Japanese pilchard
peak
year
1964
1966
1968
1968
1969
1970
1972
1972
1973
1974
1976
1977
1978
1980
1985
1986
1987
1988
peak
catch
0.7
4.1
3.9
1.7
1
13.1
0.35
1.1
0.43
0.2
0.7
0.7
3.4
1.1
6.5
6.8
0.3
5.4
1992 decline
% change
catch (m tons)
0.2
0.5
-71%
1.5
2.6
-63%
1.2
2.7
-69%
0.1
1.6
-94%
0.2
0.8
-80%
5.5
7.6
-58%
0.02
0.33
-94%
0.2
0.9
-82%
0.05
0.38
-88%
0.04
0.16
-80%
0.3
0.4
-57%
0.4
0.3
-46%
0.9
2.5
-74%
0.5
1.8
-26%
3.1
3.4
-52%
0.5
1.8
-26%
0.06
0.24
-80%
2,5
2.9
-54%
Overfishing
Marine Biodiversity
Reasons for the loss
1. Invasives
2. Climate change
- Ocean acidification, sea level rise, ocean
warming
3. Pollution and Toxics
4. Loss of habitat
- especially coastal: coral reefs,
mangroves, estuaries, etc.
5. Overfishing
Consequences of overfishing
1. Changes in marine food web
Worldwide:
Trawled Area = 150 x annual rainforest
clear-cuts
“clear-cutting the forest to catch a squirrel”
“Fishing down the marine food web”
Pew Oceans Commission
Biomass Pyramid
Consequences of overfishing
2. Habitat Destruction & bycatch
Method
Dredges
Gillnets – bottom
Gillnets – midwater
Longlines – bottom
Longlines – pelagic
Pots and traps
Trawls – bottom
Trawls – midwater
Worst
Fishing methods
Fishing Methods
(worst)
Dredge
Towed metal bag
13-15’ wide, 2400 lbs
Scallops, clams, oysters, shellfish
Monterrey Bay Aquarium
Fishing methods
Fishing methods
(worst)
(worst)
Bottom gillnet
350’ long anchored net
Sardines, goosefish, cod,
pollock, flounder, salmon
Significant bycatch
- turtles, dolphins
Bottom trawl
Towed net with weights
200’ wide, 40’ high
Shrimp, sole, flounder, rockfish
Can disrupt seafloor
Purse Seine
Encircles a school of fish
Bottom of net closed
Hauled onboard /
brought near surface
Schooling fish: sardines, tuna
Significant bycatch
Monterrey Bay Aquarium
Monterrey Bay Aquarium
Fishing methods
Fishing methods
(best)
(best)
Pelagic longline
1-50 miles long
Tuna, swordfish
Bycatch: sharks,
turtles, seabirds
Hook and Lining
Lure fish with baited lines
Surface dwellers: tuna, mahi mahi
Bottom dwellers: cod
Minimal bycatch
Pots and Traps
Wire or wood, baited cages
Crab, lobster, rockfish
Bycatch: marine mammals can
become entangled in the rope
connecting the cage to a buoy
Monterrey Bay Aquarium
Trolling
Lure fish with towed baited lines
Surface dwellers: tuna, mahi mahi
Minimal bycatch
Monterrey Bay Aquarium
Challenges to
Fisheries preservation
1. Extremely rapid human expansion
(most of world’s population lives near coasts
= finite resource vs increasing demand)
2. Damage isn’t readily visible
(underwater)
3. Seen as an inexhaustible resource
“Unless the order of nature is overthrown, for centuries to
come our fisheries will continue to be fertile.”
4. No clear jurisdiction in international waters
Solutions
• Endangered Species Act
» Whales, seals, sea lions, sea turtles
• Marine Protected Areas
» Partial protection. Some commercial fishing allowed
• Marine Reserves
» “Within 1-2 years, population densities increased
91%, average fish size up 31%, species diversity
rose 20%”
» Biggest fish caught along borders of reserves
» NOTE: only 1% of oceans are protected. Need ~30%
• Fisheries Management
» Goal: set limits to reduce catch to sustainable yield
» Current subsiies: $124 billion spent for $70 billion earned
» US Magnuson-Stevens Reauthorization Act, 2006