Executive
Summary
Boyd,
R. O.; Reilly, J. L. (2002). 1999/2000 National Marine Recreational
Fishing Survey: recreational harvest estimates.
Draft New Zealand Fisheries Assessment Report 2002/XX
Recreational harvest estimates for 1999-2000
(1 December 1999 to 30 November 2000) are presented for a
wide range of fish and shellfish species. The estimates are
based on a similar, but enhanced, survey methodology that
has been adopted for estimating recreational harvests in previous
surveys. The survey methodology involves combining results
from at three separate but related surveys. An estimate of
fisher prevalence derived from a nation-wide face to face
survey is combined with detailed diary data of recreational
harvests recorded by a nation-wide sample of recreational
fishers recruited by telephone, to estimate recreational harvests
in numbers of fish or shellfish. Estimated harvests in numbers
of fish or shellfish were converted to total harvest weight
using the results of a boat ramp survey to estimate the mean
weight of recreationally harvested fish and shellfish.
Key enhancements over previous surveys
included the use of a face to face survey for measuring fisher
prevalence, improved methods for weighting up diarists' harvests
using extensive demographic data and a more appropriate method
for estimating coefficients of variation.
Estimates for the 1999-2000 national
marine recreational fishing survey are much higher than the
estimates from previous surveys. The harvest estimate for
SNA1 which has a c.v. of 11% is in excess of 6.9 million fish
and 6 200 tonnes. Very few of the harvest estimates have c.v.s
of less than 20%. Most of the fishstock recreational harvest
estimates presented in the report are higher than previous
estimates by a factor of two to three times. Coefficients
of variation (c.v.s) for the harvest estimates are much larger
than estimated for previous surveys but are more reflective
of the complex nature of the survey design and the highly
skewed nature of diarists' harvests. These factors were not
taken into account in the method used for estimates of c.v.s
in previous surveys.
Some of the 1999-2000 harvest estimates,
particularly the estimates for a number of key fishstocks
in QMA2 appear to be implausibly high. While the reasons for
this are not known, the small sample size for this area may
have resulted in a biased sample of diarists.
Results from pilot surveys undertaken
as part of the 1999-2000 survey together with a review of
the available literature strongly suggest that previous harvest
estimates from the 1996 national survey and earlier regional
surveys are highly unreliable and probably much too low. Therefore,
caution should be exercised in comparing the estimates presented
here with the estimates from previous surveys as such comparisons
are likely to be misleading.
The improved survey methodology and estimation
procedures adopted for the 1999-2000 national marine recreational
fishing survey mean that the reported harvest estimates should
be more accurate than the estimates from prior surveys. The
much higher recreational harvest estimates have significant
fisheries sustainability and management consequences. Future
surveys to estimate recreational harvests will need to focus
on making further improvements to the survey methodology and
improving the precision of estimates.
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