Fishing = Harvesting = Predation Predator-Prey Interaction +- with Humans as Predator Very high-tech hunting- gathering –Fast boats –Sonar, fish finders –Factory on-board –Midwater, bottom trawl Artisenal harvesting –Coral reefs, intertidal

Exploited Populations Sustainable or overexploited? –Small human populations: local depletion? Deforestation of Med/Iceland Oysters in Washington State –Now: Larger human populations Global markets and distribution More people (# and %) in coastal zones

Fishing Methods Catch and Bycatch Fishing Effort: The total fishing gear in use for a specified period of time. Fishing Power: The catch which a particular gear or vessel takes from a given density of fish during a certain time interval. Bycatch: Unintended catch of organisms not part of the fishery being targeted.

Peruvian Anchovy

Small fish, live 3yr, spawn 1yr, caught 5mo+ School near surface World’s largest fishery until 1972 Major fishery started in 1955 Catch doubled every year Peak 12.3mt, 18% total fish catch

Peruvian Anchovy Cont’d Maximum Sustainable Yield estimated at about 9 million tons/year Assumes no change in environment 1972 El Nino, no upwelling/nutrients 1972 few young, lots of adults, huge catch Crash of fishery, hasn’t recovered Huge economic consequences

Principles of Exploitation Below certain levels, populations resilient – increase growth or survival to compensate for fishing losses (removal of indivs) Above certain levels, local or global extinction of the resource ($ or actual) Somewhere in middle, level of “maximum sustainable yield” – hard to apply in the real world Social resilience and precautionary principle?

Beyond Single-Species Approaches What about habitat, species interactions, climate change?

A framework for fishing pressure

Kinds of Bycatch Fish of wrong (non-target) species Fish that are of the wrong size Fish that are of the wrong sex Fish that are damaged (caused by gear or predation in the gear) Excess fish discarded when quota reached High-grading (low market value, damaged, or poor quality fish) Prohibited species - any species which must by law be returned to the sea (i.e. marine mammals, turtles, birds, and other fish) Population impacts vs economic benefit

Some Solutions to Bycatch Selective Fishing Gear –Turtle Excluder Devices (TEDs) –Deeper Longlines Integrating Fisheries and Conservation –MPAs and BFFF –No take zones, goals? Product certification

Ecosystem Based Management The effect of the environment on the resource (population biology and habitat!) The effect of resource exploitation on the environment (food webs, energy) Complex ecosystems, uncertainty, tipping points, and the precautionary principle The human factor – fishing communities, cultures, practices, and economies

Other Issues to Consider Western Science vs Traditional Ecological Knowledge Enforcement of Regulations and Rules Markets and Externalities (ITQs) Climate Change and Uncertainties of Oceans’ ability to produce fish Social and ecological resilience, coupling!