Economic Impacts of Global Over Fishing by pengtt


									Ecosystem Collapse in Global
  Fisheries due to Chronic

            Chris Coner
      Will Harrigan-Anderson
             Mike Jolly
            Jeff Schles
• 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
• In understanding the global fisheries
  problem due to social irresponsibility in
  relation to sustainable management;
  economic and ecological aspects were
    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
  – a situation that gives rise to the economist's
    notion of existence (or passive use) value
       Three essential concepts
• “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
      Three essential concepts
• “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
• 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
• 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
                                     Ecological Impacts
-Trophic level interactions can be
severely altered as a result of over-

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
• Transition from
                        Trend of mean trophic level landings in global
  longe-lived           fisheries (Pauly et al.)

  piscivorous fish to
  planktivorous fish
       Impacts of exploitation
• Loss or removal of top predator(s) results
  in alleviated pressure
  – Smaller species expand spatially and
• Studies have shown that overfishing has
  resulted major structural and functional
• Kelp Forests
  – Pacific
     • Removal of sea otter, spiny lobster
  – Atlantic
     • Removal or Atlantic Cod and other large ground
• 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
• One of world’s largest generators of
• 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
• Supplies Hong Kong,
  Mainland China, Taiwan
• Main Species: Large
  Groupers, Humphead
                                (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
• 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
• 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
              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
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