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Hugo GrotiusMare Liberum
1609• Whales• Norwegian herring• Japanese sardine• Peruvian anchovy• Can. N. Atlantic cod
• Technology• Capital Investment• Fisheries Information• Politics• Social Issues• Tragedy of commons• Population
Total Global Fisheries Harvest ~160Mt
• Year CAP AQ• 2002 94.5 52• 2003 91.8 55.2• 2004 96 60• 2005 95.5 63.3• 2006 93.1 66.7
• Capture Fisheries are constant at ~90-95Mt
• Aquaculture is steadily increasing
Table 1.1 Disposition of the total aquatic catch for 2002
Use % of total catch by weight
Human consumption 75.8
Fresh 39.7
Frozen 20.0
Cured 7.3
Canned 8.7
Reduction 19.0
miscellaneous 5.3
Why Do We Care?
• Calories
• High Quality Protein• Essential Amino Acids
• Essential Fatty Acids (w3’s, w6’s)
How the Oceans Make Fish
• Primary Production Commercial Fish
• 3 Types of Ocean Areas– Open Ocean– Coastal Areas– Upwelling Areas
Permanent pycnocline
Sea surface
sinking
Excretion, death, and sinking
grazing
Upwelling and turbulent diffusion
regeneration
phytoplankton
herbivores
carnivores
Winter mixed layer
dissolved nutrients
Nutrients in detritus
dissolved nutrients
grazing
Table 1.5 Estimates of marine primary production from Martin et al. (1987)
Province % of ocean
Area(1012 m2)
Mean production (gC m-2 y-1)
Global production(Pg C y-1)
% of primary
production
Open ocean
90.0 326 130 42.38 82
Coastal zone
9.9 36 250 9.00 18
upwelling 0.1 0.36 420 0.15 0.4
total 100 362 142 51.53 100
Open Ocean Area
• Deep• Low inputs• Mostly Regen. Nutrs.• Stable Temporally• Nutrient Limited
• Small Phytoplankton
• Long Food Chains
• Low Comm.Fish Yield– Big area– High value Needed
113 226
Algal picoplankton and nanoplankton (42,380)
Flagellates (8,476)
Ciliates (1,695)
Crustacean zooplankton (339)
Mesopelagic vertical migrators (45.2)Chaetognaths, micronekton (22.6)
Small tuna, salmon, squid (3.39)
Large tuna, sharks, billfish (0.51)
Trophic level
1
2
3
4
5
6
7
Coastal Areas
• Shallow• Seasonal Inputs• Seasonal Variability• ~50% New Nutrients• Spring bloom (40%)
• Larger Phytoplankton
• Shorter Food Chains– Clupeids
• Benthic Food Chains– Gadoid fishes– Mollusks– Crustaceans
• High Comm. Fish Yield
2816.316.3
102306
29
20
97
225408
1,800
6,000
1,200
phytoplankton (9,000)
flagellates (1,200)
ciliates (240)
crustacean zooplankton (408)
invertebrate carnivores (61)
bacteria (322) meiobenthos (19)
macrobenthos (49) epifauna (4)
pelagic fish (32.6) demersal fish (10)
large demersal fish (0.4)
natural mortalityand fishing
Upwelling Areas
• Shallow• Seasonal Inputs• Seasonally Steady• Mostly New Nutrients
• Larger Phytoplankton
• Short Food Chains
• Clupeid fish
• High Comm. Fish Yield
2.36.8
64.5
42.75
phytoplankton (150)
flagellates (12.9)
ciliates (2.6)crustacean zooplankton
(9.1)
invertebrate carnivores (1.4) pelagic fish (9.3)
natural mortality and fishing
42.75
Sustainable Catch
• SFC = Grs.Pop.Growth – Nat.Mortality
• w/o a Fishery (i.e.F=0), GPG balances NM– otherwise fish vanish, i.e. NM>GPG or– fish take over the planet, i.e. GPG>NM– In virgin fishery GPG ~NM– In early fishery FC+NM ~ GPG– As Pop declines GPG >NM
• more resources, younger stocks, etc.
Maximum Sustainable Yield
• MSY relative to virgin population
• ~25%; surely <50%
• MSY is a TERM, not a TARGET
• Why? Perturbations; bad info; unknowns
• Calc MSY ~140Mt > Catch ~90Mt
D=$10,000, I=10%/y, Ic=constant, W=$0, Wc=constant
Y YEBbW W YEBaW0 $11,000 0 $11,000
1 $12,100 0 $12,100
2 $13,310 0 $13,310
3 $14,641 0 $14,641
4 $16,105 0 $16,105
5 $17,716 0 $17,716
6 $19,487 0 $19,487
7 $21,436 0 $21,436
8 $23,579 0 $23,579
9 $25,937 0 $25,937
10 $28,531 0 $28,531
D=$10,000, I=10%/y, Ic=constant, W=$1000, Wc=constant
Y YEBbW W YEBaW0 $11,000 1000 $10,000
1 $11,000 1000 $10,000
2 $11,000 1000 $10,000
3 $11,000 1000 $10,000
4 $11,000 1000 $10,000
5 $11,000 1000 $10,000
6 $11,000 1000 $10,000
7 $11,000 1000 $10,000
8 $11,000 1000 $10,000
9 $11,000 1000 $10,000
10 $11,000 1000 $10,000
D=$10,000, I=10%/y, Ic=constant, W=$1000, Wc=fluctuating
Y YEBbW W YEBaW0 $11,000 1000 $10,000
1 $11,000 2000 $9,000
1 $9,900 1000 $8,900
2 $9,790 500 $9,200
3 $10,219 1000 $9,219
4 $10,141 500 $9,641
5 $10,605 2000 $8,605
6 $9,465 1000 $8,465
7 $9,312 1000 $8,312
8 $9,143 500 $8,643
9 $9,508 500 $9,008
D=$10,000, I=10%/y, Ic=fluctuating, W=$1000, Wc=constant
Y YEBbW W YEBaW0 $10,500 1000 $9,500
1 $10,450 1000 $9,450
2 $9,639 1000 $8,639
3 $9,503 1000 $8,503
4 $9,353 1000 $8,353
5 $8,938 1000 $7,938
6 $8,732 1000 $7,732
7 $8,505 1000 $7,505
8 $8,631 1000 $7,631
9 $8,241 1000 $7,241
10 $8,182 1000 $7,182
Unconventional Fisheries
• Antarctic Krill– NM~400Mt/y; MSY >> 60Mt/y– Variable biomass, distant, shelf life, taste– Krill butter, cheese, sausage, (not high-value)
• Midwater fish– myctophids, lanternfish, MSY >>110 Mt/y
• Squid– C~3Mt/y; whales~100Mt/y; MSY~25Mt/y
Characteristics of Deep-Sea Habitats
benthopelagic
Why care? - The Deep-Sea is HUGE!
• ~70% of the earths surface is covered by the oceans
• ~90% of this area is water with depths greater than 200 meters
• The deep-sea is the single largest living place on the planet
Deep-sea fisheries are expanding
orange roughy
rattails (grenadiers)
patagonian toothfish
(chilean seabass)
Counter illumination – the use of bioluminescence to eliminate the ventral shadow
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