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Biology 1229
Fisheries…
or…
Should fish be on the
menu?
Fish on the menu…
 At
least 2.5 Billion people depend
on fish for more than 20% of the
protein in their diet
 97 % of fishers are in developing
countries
Why might fish be on the list?
 Mercury
Why might fish be on the list?
 Farming
practices unsustainable
Shrimp farming in Mexico destroys
mangrove forests
 Salmon farming




Escapes
Parasites
Eutrophication
Why might fish be on the list?
 Fishery
unsustainable or
environmentally damaging
Bottom trawling
Bycatch from a shrimp
net!
Unsustainable fisheries
How does a harvested
population work?
Note:
“sustainable” is
economic, not
based on the
population!!!
 It is possible to
derive a MSY
from population
data using
growth rate and
harvest rate

Orange Roughy
Hoplostethus atlanticus
 Slow,
ugly, demersal fish
(“Slimehead”)
 Mature at 20-30
 Live up to 156 years (depending
on who you listen to…)
 Harvested by bottom trawling
around sea mounts
 Fishing, or mining?
How much of the ocean is
harvested?
Fishing down the food web
How many fisheries are
sustainable?
What about recreational fishing?
Commercial Fishery
Including menhaden and pollock
Recreational
fishery as a %age
of commercial
But the vast majority of several high-value, threatened
species (e.g. Red Snapper) are caught recreationally
We are catching too
many fish!!
Not just fish suffer…
 Effects
on seabirds & other top
predators
 Effects on erosion and flood
control (e.g. New Orleans)
 Economic effects of fishery
collapse (Newfoundland)
Top 20 countries for
unsustainable fishing…
1.
2.
3.
4.
5.
18.
China
Peru
Japan
Chile
USA
Canada
What future?
 Some
authors predict the
collapse of ALL fisheries by 2048
 Sustainable management is
possible… requires
Reliable data
 Reliable fisherman
 A pretty decent navy

 End
of oil may result in reduced
fishery pressure
Ownership of fisheries
prevents collapse
With ITQ
Without ITQ
Number of Individual
transferable quota
(ITQ) fisheries
See also
http://www.mbayaq.org/cr/seafoodwatch.asp