Fisheries Case Studies Japanese Pilchard (Anchovy) Norwegian Spring-Spawning Herring Canadian...
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Fisheries Case Studies
• Japanese Pilchard (Anchovy)
• Norwegian Spring-Spawning Herring
• Canadian Pacific Herring
• Canadian Atlantic Cod
• North Sea Cod
• North Sea Herring
Clupeid & Gadoid Fisheries
r – Selected Species
~1/3 Global Fisheries
Instability Management Challenges
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
Anchovies
Sardines
Herring
Geographical distribution of the four subpopulations of Japanese pilchards and annual catch by region from 1972 to 1976. Numbers in circles are catch in thousands of tonnes.
Kuroshio Current
Norwegian spring-spawning Herring
Commercial catch, recruitment of 3-year old fish, and spawning biomass of Norwegian spring spawning herring.
Percentage contribution of year classes of Norwegian spring spawn herring to the adult stock from 1954 through 1962. The very good year class of 1950 began first appearing in significant numbers in 1954 and dominated the adult stock throughout this period.
Cod, Haddock, Pollock
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
(A) Catch of North Sea Herring and (B) spawning stock biomass of the autumn spawning herring. The dashed line in panel B is the target spawning stock of 1.3 Mt recommended by the ICES.
Harvest of sexually immature fish
Over Capitlizat’n
Habitat destruction
Recruitm’t overfishing
Closure of fishery
Japanese Pilchards
Norwegian spring-spawning Herring
Canadian Pacific Herring
Canadian Atlantic Cod
N. Sea Cod
N. Sea Herring
Species to Avoid
• Chilean Sea Bass
• Orange Roughy
• Atlantic Halibut
• Bluefin Tuna
• Shark
• Atlantic Swordfish
Chilean Sea Bass
• Dissostichus eleginoides• Patagonian toothfish• Z = 150 – 12,500 feet• W ≈ 20 lb; age ≤ 50 yr• Sexual maturity ≈ 6-10 yr • Population doubling time ≈ 5=14 yr• Very long w.r.t. many Com’l fisheries• K-species
Orange Roughy
• Hoplostelhus altanticus• Mesopelagic habitat (3-9°C, 200-2000 m)• Atlantic and Pacific Oceans• Age ≤ 150 yr• Large spawning aggregations• 20,000 eggs/clutch; ferthatch =10-20d• Sexual maturity at 25-30 yr• K-species