Home' Ausmarine : August 2009 Contents only eight from 367 tagged animals (i.e. 2.2 percent recapture)
suggest a much lower depletion rate.
In addition, there are also large areas that are unfished or little
fished because cray abundance there is too sparse to yield
worthwhile catches. Nevertheless, the unfished population over
such areas may still be quite large in total.
The probability of error in estimates based on complex
interactive models involving numerous assumptions and estimates
is high. Verification of results by direct methods such as catches,
diving or video based surveys is essential.
Reliance on unverified models is a recipe for disaster. Reliance
on unverified financial risk modelling played a major part in the
current global economic recession.
As (under)stated in the 2007 Western Rock Lobster Stock
Assessment and Harvest Strategy Workshop with regard to
depletion study, "precision might be improved".
Increasing efficiency by fabrication
As also (under)stated in the same 2007 workshop report,
"Efficiency increases are not based on rigorous recent estimates." It
might be added that efficiency increases have never been based on
rigorous estimates but have only been based on estimates as
desired to explain away discrepancies between modelled
predictions and actual catches.
It is well known that the long planktonic larval stage of lobsters
make their recruitment highly susceptible to variables in oceanic
conditions. Lobster fisheries everywhere are characterised by large
erratic inter-annual fluctuations.
Still, WRLF management has been strangely reluctant to
attribute decreases in catch to anything other than overfishing and
increases to anything other than increasing efficiency. Unlike all
other lobster fisheries, the WRLF is apparently never expected to
have good years. Whether catch increases or it decreases, it's
evidence of overfishing and more restrictions are called for.
While bigger faster boats, hydraulic pullers and improvements
in navigation equipment and depth sounders have unquestionably
made life easier for fishermen the effect on catch per trap has been
As noted above the average catch per pot in 1973-82 increased
only 17 percent in 1999 to 2008. Average puerulus counts over the
same periods increased by 75 percent. How much of the 17 percent
increase in catch per pot (or 14 percent increase in total catch) is
attributable to increased efficiency and how much to a natural
population increase is highly uncertain.
The only certainty is that a steady ongoing increase in
efficiency of one to two percent a year has no evidential basis but
is only a figure fabricated to support a desired outcome.
Catchability -- politics not science
Crayfish catches often vary widely from one day to another in
accord with weather and sea conditions. Temperature, lunar phase,
migratory activity, bait and repeated fishing in the same location
also affect catchability.
Fishermen have long been aware of these influences and use
them to advantage when possible. Fishery managers have recently
discovered catchability to be a convenient alternative explanation
for improved catches when claims of increased efficiency might
risk a need to explain.
Although catchability and increased efficiency are real
phenomena, so too are large natural fluctuations in recruitment.
To use the former to deny the latter is politics not science. A
rigorous assessment of these effects is an obvious management
deficiency requiring attention.
There are significant differences in the fishery between the
different fishing zones. Management measures that may be
desirable in one area can be undesirable in another. Consideration
needs to be given to greater separation of industry representation
and of the management measures imposed on different zones.
Despite ongoing concerns, the long-term performance of the
fishery shows no evidence of overfishing nor is there any reason to
expect it. The WRLF harvest rate per unit of area is lower than
most other lobster fisheries and the population density (as
evidenced by the catch per trap pull) is higher than most.
Maximum economic yield
Reid (2009 -- An Analysis of Maximum Economic Yield in the
Western Rock Lobster Fishery, Fisheries Occasional Publication
No. 60) has advocated changing the aim of managing the WRLF
from Maximum Sustainable Yield (MSY) to Maximum Economic
The claims made in this study are inconsistent with the actual
performance of the fishery which is one of the most profitable. It
appears clear that the real aim is further downsizing of the industry
with expanded management responsibility and authority. This
study could arguably be seen to be an investment prospectus
offering enhanced profitability for the industry under Department
of Fisheries management.
Viewed as an investment prospectus, some of the claims made
would appear to breach legal limits for what can be claimed in
such a document.
Introduction of quotas
Quotas will eliminate good catch years and primarily benefit
less productive fishermen while curtailing the most productive.
The history of quotas in other Australian fisheries has typically
been one of ongoing cutbacks with large costs to buy more quota
and the most lucrative resources becoming increasingly owned by
investors and corporations.
Being already fully established and operating sustainably
provided the WRLF some relief from the hypothetical concerns
and precautionary measures that have stunted and strangled
less developed sectors. This advantage, however, has been
only relative and temporary. The WRLF now suffers under
various restrictions of dubious merit and their cumulative
burden is increasing. It can also expect to receive increasing
attention as other less profitable fisheries are managed into
extinction and a bloated bureaucracy turns increasing attention
to surviving sectors.
The good news is that as the fishing industry downsizes from over
regulation all this expensive management won't be needed either.
Recently Fisheries New South Wales announced significant staff cuts
in response to budget reductions. For state governments facing large
falls in revenue, expanded fisheries departments managing
downsized fisheries will be obvious candidates for cutbacks.
AUSMARINE August 2009 21
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