Impact of Fishing on the Abundance of Marine Species

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Impact of Fishing on the Abundance of Marine
Species

• Rainer Froese
• IfM Kiel
• rfroese_at_ifm.uni-kiel.de

Kathleen Kesner-Reyes MSI Quezon
City kkesner_reyes_at_hotmail.com
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Background

• Fishing down the food web gtgt
• Global catch declining gtgt
• Fish biomass in the North Atlantic gtgt

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Materials and Methods

• FAO Production data, 1950-1999, for marine areas
  only, no bivalves, seaweeds, corals
• ICES Catch data, 1973-1999
• Species items treated as fisheries
• North Sea Catch data 1903-1998 (SAUP)
• Resilience and Trophic Level from FishBase
  www.fishbase.org

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Materials and Methods (Basking shark)
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Material and Methods
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FAO Marine Catches 1951-1998
?
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Overfishing is Increasing
Percentage of species items in FAO production
data that were overfished within 10 years after
the fishery was first fully exploited.
8
New Resources Species Composition
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Resilience / Productivity of SpeciesMusick,
Fisheries 1999
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Dynamics of OverfishingCatch by Resilience /
Productivity Group
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Recent Status of Best Perfomers

• Of 25 fisheries that had 30 or more fully
  exploited years before 1989, thereafter
• 8 were partly (1-9 years) overfished
• 2 were fully (10 years) overfished
• 1 was collapsed

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The Northeast Atlantic, ICES
?
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Overfishing in the North Sea
Sandeel
Catch composition of landings from the North Sea
from 1903 to 1998
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Fishing Down the Food Webin the North Sea
Trends in mean trophic level of annual landings
from the North Sea
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Impact of Fishing on CoML

• No extinctions of marine species due to fishing
  yet
• Near extinctions and extirpations are
  increasing
• Abundances of most organisms are drastically
  altered from virgin state
• CoML must deal with Shifting baseline effect

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Most landed fish are immature
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New Approaches
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New Approaches
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New Approaches
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New Approaches

• Restrict fishing to cohort after first and before
  second spawning
• Determine amount to be taken from ecosystem
  studies
• Involve ALL stakeholders AND the public

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Dynamics of Overfishing

• Discussion
• Thank You

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Dynamics of OverfishingFishing Down the Food Web
gtgtPauly et al., Science 1998
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Dynamics of OverfishingFishing Down Size
ltltFroese et al. 2000
Canada, Northwest Atlantic
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Dynamics of Overfishing ltltWatson Pauly, Nature
2001