Marine Biodiversity and Fisheries Management November 29 th, 2006 For section this week: look at last year’s final exam and Valuation homework (both are on course website). Come to section with questions.

Valuing Biodiversity: Key Points  Externalities  Cost/Benefit analysis  Valuation methods (substitutes, revealed pref’s, contingent valuation)  Calculating C/B under uncertainty: Expected Value  Discounting the Future: Net Present Value Calculations  Sustainable management: tends to have costs now, benefits later  Discounting makes Benefit:Cost ratio look worse  Example: organic, crop rotation based agriculture  Unsustainable management: tends to have benefits now, costs later  Discounting makes Benefit:Cost ratio look better  Example: Continue to use fossil fuels instead of renewable energy

Importance of Marine Resources:  PROTIEN  Especially in LDC’s  EMPLOYMENT  Especially in LDC’s  Recreation, tourism, intrinsic values…  What happens when marine resources become scarce?

Marine harvest seems to have leveled off… Human population growth has not!!!

Humans as Optimal Foragers: prey switching

Fisheries: Classic Example of T.O.C.  Before 1982, fisheries were an “open access” resource  T.O.C: profit-seeking individuals will over-exploit a resource that is unrestricted (open-access)

Fisheries: Classic Example of T.O.C.  Before 1982, fisheries were an “open access” resource  T.O.C: profit-seeking individuals will over-exploit a resource that is unrestricted (open-access)  1982: UN passes the “Law of the Sea” out to 200 nautical mi.  Countries bordering oceans can claim exclusive economic rights of ocean harvest out to 200 nautical mi.  Did this “privatization” work?

The Problem: Source: United Nations Food and Agriculture Organization: The Status of World Fisheries and Aquaculture, 2002

Key Terms  Stock – total population or biomass  Recruitment - influx of new members into a population by reproduction or immigration  Harvest – how many are extracted  Effort – how hard fisherman try to harvest (could be measured by # of boats, # of hours spent fishing…ect)  Bycatch- the unintentional harvest of species

Set limit on fishing using MSY model Remember the logistic growth model???

Set limit on fishing using MSY model Population growth rate isn’t always density dependent!

Set limit on fishing using MSY model Theory: If harvest = growth rate, population size will stay the same

MSY model with Stochasticity

What happens if you Over-harvest? Point A Sustainable, below MSY B Sustainable (risky) C Unsustainable (above MSY) D Sustainable (safe) E Sustainable, below MSY

Why are fish getting smaller? Fig Declines in the average size of the five most important fish species landed by sport-fishing boats in the southeastern U.S. from

“Fishing down” the food web  Shift to lower trophic levels (sardines, herring, ect)  Anomoly from Peruvian anchovy fishery  Did we learn from its collapse?learn  Dynamics of harvesting large predatory fish  Fisheries take much longer to rebuild than to deplete

How do countries over-exploit their own resources?  Discounting & Subsidies: China  Ineffective Management  Trouble assessing population levels  Environmental fluctuation  Over-reporting catches (competition + globalization)  Fish dynamics (movement + growth dynamics)  Trouble enforcing limits  Technological Advances to catch fish  Bycatch

Dynamics of Orange Roughy: yummy, mild fish

Orange Roughy Population Decline

Atlantic Cod Fishery Collapse

How do countries over-exploit their own resources?  Discounting and Subsidies  Ineffective Management  Trouble assessing population levels  Environmental fluctuation  Over-reporting catches (competition + globalization)  Fish dynamics (movement + growth dynamics)  Trouble enforcing limits  Technological Advances  Technological Advances to catch fish  Bycatch

The Role of Technology

How does a ‘cheap’ fishery compare with an ‘expensive’ fishery? Cost or Benefit ($/time) Expensive Fishery Cheap Fishery How can you get the same yearly fish yield, with less boats?

Bycatch: Externalities

Management Options  Technology  Limit technology  Use technology to decrease bycatch

The Role of Human Values and Perceptions Scarcity price increases: Expected Value of fishing? Establishing and shifting baselinesshifting baselines

Management Options  Fix problems identified with privatization  Better population assessments  Technology  Fines/Permits  Inform Consumers-change perceptions --- Shift focus from individual stocks to ecosystems ---  Marine Reserves  Aquaculture Next time!