| 1999/2000
National Marine Recreational Fishing Survey:
harvest
estimates released
September
2002
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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