Productivity over long time periods
Both the Australian and U.S. Government have recently released
productivity reports which examined productivity trends
over long time periods for key fisheries [8,15]. These studies were
notable because they examined productivity trends for a large
number of fisheries over varying time periods using a standard
methodology. Outside of studies produced by national fisheries
agencies, relatively few studies examined productivity over a 20
year or more time horizon [6,16,21,30,31]. Generally, these studies
attempted to match productivity change with policy changes
which took place during the study years. It is also worth noting
that all three studies used different methods, yet had similar
conclusions.
The first study was of productivity change in the New England
groundfish fishery over a 30 year time period using a Törnqvist
index [16]. Results showed that productivity increased in spite of
different regulatory policies, and declining biomass. Biomass
change was calculated using revenue shares of landings for each
species, and research vessel survey abundance indices for biomass.
The resulting term was simply subtracted from the output and
input portions of the overall productivity index. Failure to adjust
for biomass change yielded a result where productivity declined
6.6%, while accounting for biomass change meant that TFP increased
4.4%. A second set of measures which adjusted the productivity
metric for changes in capacity utilization showed the
same trend. Under increasing regulatory constraints which were
enacted to stop declines in fish stock abundance, the authors
found that there were periods where productivity growth stagnated.
They concluded that ultimately, regulators were unable to
strike a balance between productivity growth and restoring resource
abundance.
A second study published at virtually the same time as the
work cited above also used a Törnqvist index to measure productivity
change in Icelandic fisheries over a 20 year time period
[20]. This study, previously mentioned above, used the phrase
“three factor” productivity (3TFP) as a metric which included
biomass, along with the inputs of capital and labor. In order to
adjust for biomass, an elasticity of output of 0.1 was assumed for
pelagic species, and 0.85 was assumed for other stocks. Results
showed large gains in 3TFP over the period 1974–2004 for Icelandic
fisheries. The gains were much larger than other sectors in
the Icelandic economy and other fishing sectors abroad. It was
speculated that much of the gain was driven by increased effi-
ciency rather than technical change.
A third study measured productivity trends for capture fisheries
in Norway between 1961 and 2004 using a growth accounting
framework [6]. There were several important points