BIOL468 & ECOL198Univ of Liverpool

Lecture Overheads: The Tragedy of the Commons

By Dr Rick Leah

Overfishing

Increased fishing – decreased abundance

Decreased fishing – increased abundance of fish

The ‘Great Fishing Experiment’ – World War 1

The Tragedy of the Commons," Garrett Hardin, Science, 162(1968):1243-1248.

The Tragedy of the CommonsGarrett Hardin (1968)

  • An implicit and almost universal assumption of discussions published in professional and semi popular scientific journals is that the problem under discussion has a technical solution.
  • Nature of such problems: No technical solution

(sometimes called wicked problems)

  • Finite world, Exponential growth – linked to population
  • Optimum population – less than the maximum
  • Difficulty in defining the optimum
  • Maximum good per person – but what is it?
  • Has any group solved the problem – even at an intuitive level? – No

Tragedy of Freedom in a Commons

"the tragedy of the commons," using the word "tragedy" as the philosopher Whitehead used it :

"The essence of dramatic tragedy is not unhappiness. It resides in the solemnity of the remorseless working of things.”

the inherent logic of the commons remorselessly generates tragedy.

Freedom of the seas - inexhaustible resources of the oceans

National Parks – sell off as private property, public property but allocate the right to enter

Mutual Coercion Mutually Agreed Upon

An alternative to the commons need not be perfectly just to be preferable.

Recognition of Necessity

Perhaps the simplest summary of this analysis of man's population problems is this: the commons, if justifiable at all, is justifiable only under conditions of low-population density.

As the human population has increased, the commons has had to be abandoned in one aspect after another.

Overfishing may be one of three kinds :

1Growth overfishing
when the young fish recruits to the fishery are caught before they reach a reasonable size / age

2Recruitment overfishing -
when the parent stock is so reduced that not enough young are produced for the fishery to maintain itself

3Ecosystem overfishing -
in a mixed fishery when the catch decline through fishing of the original abundant stock is not compensated for by the contemporary or subsequent increase of other exploited animals
ie the transformation of a relatively mature, efficient system into an immature, inefficient system

The human dimension of fisheries science

Objectives of fishery management

Who owns the fishery and for whom is it managed?

The problem of uncertainty

Development to increase Economic Efficiency or Freedom?

Sustainable development

The Ecological Dimension of Fisheries Science

Ecosystem structure

Methods of management

  • Restriction/regulation of access – closure of the “commons”
  • Closures of fishery in time
  • Size limits
  • Gear Restrictions
  • Total catches
  • Stocking
  • Scientific basis of management – year class fluctuations
  • Bioeconomics
  • Problem with control measures being designed by biologists with sole attention paid to the production side of the problem and not to the cost side
  • Complex interactions – multiple species

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