Economic Impacts of Global Over Fishing by pengtt

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									Ecosystem Collapse in Global
  Fisheries due to Chronic
        Over-Fishing

            Chris Coner
      Will Harrigan-Anderson
             Mike Jolly
            Jeff Schles
                            Overview
• Objectives
   – Three essential concepts
       • Preferences, Lack of control, and Lack of Information
• Ecosystem Approach to Management
   – Steps towards improvement
   – Open access fishing
   – Solutions
• Ecological Impacts
   – Decrease in trophic levels
   – Impacts of exploitation
   – Examples
• Economic Impacts
   – Background
   – Impacts
   – Case studies: Southeast Asia, Ghana, Iceland
               Objectives
• In understanding the global fisheries
  problem due to social irresponsibility in
  relation to sustainable management;
  economic and ecological aspects were
  evaluated.
    Three essential concepts
• “Preferences”
  – An example of this concept is the discussion
    of people preferring the ocean with whales in
    it even if the presence of whales has no
    influence on the production of anything else of
    value
  – a situation that gives rise to the economist's
    notion of existence (or passive use) value
       Three essential concepts
             (continued)
• “Lack of control”
  – Pertains to some event, like the roll of a dice,
    where influence by people is insignificant.
  – For example the control of weather, the ocean
    currents, the climate, or the processes of
    recruitment to fish stocks; cannot be
    influenced by managers or anyone for that
    matter
      Three essential concepts
            (continued)
• “Lack of information”
  – A risk that is independent of the ability to
    control the underlying process.
  – An example of this is a storm causing
    substantial loss of life at sea without warning.
    With appropriate weather information, and the
    knowledge that a storm is coming, vessels will
    stay in port and losses will be minimized.
Relationship between components and determinants of risk in fishery management (Huppert 1996)
An Ecosystem Approach to Management
    Steps Toward Improvement
• Ecosystem analysis of marine fisheries
• Spatial analysis of fish habitats
• These analyses must be prior to fishing!
• Implementations of “no-take” zones
• “No-take” zones must be physical and
  temporal
• Eliminate “open-access” fishing!
  Open-Access Fishing
Open access is the condition where access to the
fishery (for the purpose of harvesting fish) is
unrestricted; i.e., the right to catch fish is free and
open to all.
    A Solution for Everybody?
• “Open-access” fishing is lucrative
• Over-harvesting leaves fishermen with a
  lot of product
• Lots of product means less demand
• In the early 90’s, the market value of cod
  dropped
• A direct result of over-harvesting
          Solutions Cont’d
• Fishing industry has 53 times the average
  industrial mortality rate
• Limiting “open-access” will save lives
• Enforcing quotas will save ecosystems
• Productive ecosystems will save
  businesses
                                     Ecological Impacts
-Trophic level interactions can be
severely altered as a result of over-
fishing.




Figure 2: (a) Trajectories of collapsed fish and invertebrate taxa over
the past 50 years (Diamonds, collapse by year; triangles, cumulative
collapses.) Data are shown for all (black), species-poor (<500
species, blue), and species-rich (>500 species, red). Regression
lines are best-fit power models corrected for temporal
autocorrelation. (b) Map of all 64 LMEs, color-coded according to
their total fish species richness. (c) Proportion of collapsed fish and
invertebrate taxa (d) average productivity of noncollapsed taxa (in
percent of maximum catch)
 (Worm et al. 2006).



                                                                          Worm et al. 2006
     Decrease in trophic levels
• Fishing down the
  food web
• Decline in trophic
  levels
• Transition from
                        Trend of mean trophic level landings in global
  longe-lived           fisheries (Pauly et al.)


  piscivorous fish to
  short-lived
  planktivorous fish
       Impacts of exploitation
• Loss or removal of top predator(s) results
  in alleviated pressure
  – Smaller species expand spatially and
    numerically
• Studies have shown that overfishing has
  resulted major structural and functional
  changes
          examples…
                   Examples
• Kelp Forests
  – Pacific
     • Removal of sea otter, spiny lobster
  – Atlantic
     • Removal or Atlantic Cod and other large ground
       fish
                  Examples
• Water Quality

  – Chesapeake Bay
    • Decline in water quality (i.e. eutrophication)
      correlated to decline in oyster populations
    • Act as filters through suspension feeding
Economic Impacts of Global
      Over Fishing

        Southeast Asia
           Ghana
           Iceland
             Background
• One of world’s largest generators of
  revenue
• Extremely important for many coastline
  nations worldwide
• Over fishing one of major causes of
  potential industry collapse
               Southeast Asia
              Live Reef Fish Trade
• Comprised of Indonesian
  Island Countries
• ~1 Billion USD Annual
  Revenue
• Supplies Hong Kong,
  Mainland China, Taiwan
• Main Species: Large
  Groupers, Humphead
  Wrasse
                                (Cesar et al 2000).
       Over Fishing Impacts
• Fish harvested as fry or fingerlings
• Grown to maturity in captivity
• Caused a decrease in reproducing adults
  in the wild
• Leading to a severe decline in fish
  populations
                  Ghana
• Fisheries account for ~380 million dollars
  of economic revenue
• Support 56 million people
• No outside commercial fishing allowed in
  Ghana’s waters (only Ghana natives)
• Ghana natives also not allowed to fish
  neighboring countries’ waters
    Lack of Local Enforcement
• Key species: Sardinellas, Trigger Fish,
  Club Mackerel
• Causing ecosystem degradation, as well
  as a collapse of the fishing industry
• These species rapidly disappearing
• 56 million people in jeopardy of losing their
  jobs
                 Iceland
• Fishing accounts for 63% of total exports
• 10% of the nation’s workforce
• Iceland has defended its valuable Cod
  fisheries from other countries
• This has caused over fishing by its own
  people
              Iceland’s Goals
•   Currently fishing 45% of fishable stock
•   Goal is to reduce this amount to 25%
•   Limiting use of fishing grounds
•   Implementing quotas to limit fish landings
        Global Ramifications
• Studies show, annual fishing harvests
  could rise 10 million metric tons, $16
  billion to gross worldwide revenues
• Key is to allow fish populations time to
  recover, reproduce
• $2.9 billion increase in US alone if
  sustainable practices reached
    How it really works now…
• However, world’s fishing harvests growing
  at half the rate of fishing fleets
• This has caused ~75% of the world’s
  fisheries to be considered fully exploited
• All nations affected in some way,
  economically or socially
• These unsustainable practices are leading
  to the potential economic collapse of entire
  nations
                                    Literature Cited
•   Atta-Mills, J., Alder, J., & Sumaila, U. The Decline of a Regional Fishing Nation: The Case of Ghana and West Africa. Natural Resources
    Forum 28. 2004. 13-21.
•   Babcock, E.A., Pikitch, E.K., McAllister, M.K., Apostolaki, P., and Santora, C. 2005. A perspective on the use of spatialized indicators for
    ecosystem-based fishery management through spatial zoning. Journal of Marine Science.62: 469 – 476.
•   Botsford, L. W., Castilla, J. C., Peterson, C. H. 1997. The Management of Fisheries and Marine Ecosystems. Science. 277: 509 – 515.
•   Cesar, H., Warren, K., Sadovy, Y., Lau, P., Meijer, S., & Ierland, E., Marine Market Transformation of the Live Reef Fish Food Trade in
    Southeast Asia. Collected Essays on the Economics of Coral Reefs. CRDIU, Kalmar University, Sweden. 2000. 137-157.
•   Declining Cod Stocks Threaten Iceland’s Economy. Planet Ark. Stockholm. 3 Dec 2001.
•   Hughes, T.P. 1994. Catastrophes, Phase Shifts, and Large-Scale Degradation of a Caribbean Coral Reef. Science 265:1547.
•   Huppert, D.D. 1996. Risk assessment, economics, and precautionary fishery management. FAO Fisheries Technical Paper. 350: 103 –
    128.
•   Jackson, J.B.C., Kirby, M.X., Berger, W.H., Bjorndal, K.A., Botsford, L.W., Bourque, B.J., Bradbury, R.H., Cooke, R., Erlandson, J., Estes,
    J.A., Hughes, T.P., Kidwell, S., Lange, C.B., Lenihan, H.S., Pandolfi, J.M., Peterson, C.H., Steneck, R.S., Tegner, M.J., Warner, R.R.
    2001. Historical Overfishing and the Recent Collapse of Coastal Ecosystems Science Magazine. 293: 629 – 637.
•   Kenneth T. Frank, Brian Petrie, Jae S. Choi,William C. Leggett. 2005. Trophic Cascades in a Formerly Cod-Dominated Ecosystem.
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•   Newell, R. I. E. 1988. Understanding the Estuary: Advances in Chesapeake Bay Research Chesapeake Bay Research Consortium: 536-
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•   Pauly, D., Christensen, V., Dalsgaard, J., Froese, R., & Torres Jr., F. 1998. Fishing Down Marine Food Webs. Science. 279: 860 – 863.
•   Rosser Jr., J.B. 2002. Implications for fisheries policy of complex ecological-economic dynamics. Nonlinear Dynamics, Psychology, and
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