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Case study of sardines and anchovies indicates that natural variability
in marine populations is real and large
in the absence of fishing
It took decades to realize the importance of different mechanisms
of change, such as decadal-scale variability
A combination of oceanographic surveys and paleo studies indicate that both population
size and distribution of fish and many other marine organisms vary tremendously,
perhaps coherently, in different regions of the world’s oceans
Previously unseen populations of anchovies suddenly appeared in sardine catches in the Gulf of
California in 1986
Holmgren and Baumgartner, 1993
Ecosystem Management(hard)
orEcosystem Awareness
(soft ecosystem management)
Climate Linkage Hypotheses(non-exclusive, non-exhaustive)
• Changes in basin-scale flow affect larval transport and survival (MacCall)
• Mesoscale eddies affect larval transport and survival (Smith)
• Energy flow through food web (productivity) determines larval recruitment (Chavez)
Hypotheses can be tested with sedimentary records
Hypotheses can be tested with sedimentary records
Santa Barbara Basin sediments
indicate large climate changes in past 60,000 years that all living marine
populations have experienced
But future changes may
differ from past changes
Fisheries lessons are selectively being applied to other regions
(Namibia, spiny lobster, striped bass)
Legal, economical and cultural changes are other important possibilities
• Invest in technology to preserve fish at sea
• Find better uses and recipes
• Change cultural views
Anchovy - cheap, nutritious The government subsidizes the soup kitchens, and the fish institute decided to use them to offer anchovy-based meals and to provide training in fish preparation (FAO).
10% efficiency
Sardines were once considered a tasty treat in California.It is time for another social and cultural regime shift!