LETTER

LETTER

Evidence of bias in assessment of fisheries
management impacts
Elisabeth Slootena,1, Glenn Simmonsb, Stephen M. Dawsonc, Graeme Bremnerd, Simon F. Thrushe,
Hugh Whittakerf, Fiona McCormackg, Bruce C. Robertsona, Nigel Haworthh, Philip J. Clarked, Daniel Paulyi,
and Dirk Zelleri

Melnychuk et al.’s comments in PNAS (1) that successful fisheries management requires the “capacity to
limit fishing pressure” and “scientists are generally
unanimous in calling for stronger management” echo
comments made in many earlier publications. However, their conclusions about specific fisheries and
management approaches lack credibility.
Their analysis relies on an opinion survey, using a
nonrepresentative sample. For example, the seven New
Zealand (NZ) respondents included three fishing industry
employees or consultants, one person working for the
Ministry for Primary Industries (MPI) and one person
working for the agency responsible for stock assessment.
The other two respondents remain anonymous.
Other NZ fisheries experts are much less optimistic,
highlighting the lack of scientific data available to run
the Quota Management System (QMS) (2). Most NZ
stock assessments rely on catch/effort data provided
by the industry rather than fisheries-independent surveys. This approach is known to be one of the reasons
for consistent overestimation of Canadian cod stocks
until they collapsed in 1992 (3). Very few fish stocks
have targeted research surveys. Three quarters of
QMS stocks have no formal stock assessment (4). For
example, “estimates of reference and current biomass
are not available” for warehou (Seriolella brama) (5).
Funding for stock assessment is about 45% of levels
in the early 1990s, whereas the number of QMS stocks
has increased 3.5-fold (6).
Unintended consequences of fishing (e.g., unsustainable by-catch of endangered dolphins in inshore
gillnet and trawl fisheries, sea lion by-catch in the trawl
fishery) are just as important, but ignored. Most stock

assessments, in NZ and elsewhere, consider only the
target species, ignoring wider ecosystem effects, even
those impacting the target species.
Data on ecological impacts are inadequate for most
NZ fisheries (2). For decades, government reports recommending increased observer coverage have been
ignored. Current coverage is only 8.4% (4) and <1%
in most inshore fisheries (7). An independent review
of the MPI’s handling of illegal fish dumping and dolphin by-catch (8) demonstrated industry capture of the
regulator and revealed other serious problems. Widespread illegal dumping and misreporting have distorted catch statistics for decades (9, 10).
Fisheries management needs broadening beyond
stock assessment and management actions to reduce
fishing pressure so as to encompass more ecosystembased objectives. Cultural perspectives are also important. For example, for NZ M 
aori, the “business of
fishing” now largely means trading quota instead of
their traditional role of guardianship over fisheries.
Guardianship over the environment is very different
from guardianship over quota rights.
In summary, Melnychuck et al.’s analysis (1) is not a
trustworthy evaluation of the effectiveness of fisheries
management. Given the strong bias in the NZ sample, it
would be surprising if NZ was the only country for which
there were problems with the selection of respondents.
Instead of providing a robust analysis of the effectiveness of fisheries management, Melnychuck et al. (1)
seem to be arguing for business-as-usual while ignoring
broader issues, such as ecosystem impacts, environmental change, and social outcomes. Such an analysis
does fisheries management no service.

1 Melnychuk MC, Peterson E, Elliott M, Hilborn R (2017) Fisheries management impacts on target species status. Proc Natl Acad Sci
USA 114:178–183.
2 McKoy J (2006) Fisheries resource knowledge, management, and opportunities: Has the Emperor got no clothes? New Zealand’s
Ocean and its Future: Knowledge, Opportunities and Management. Proceedings of a Conference Organized by the Royal Society of

a

Department of Zoology, University of Otago, Dunedin 9054, New Zealand; bNew Zealand Asia Institute, University of Auckland, Auckland 1142,
New Zealand; cDepartment of Marine Science, University of Otago, Dunedin 9054, New Zealand; dQuadrat (NZ) Ltd., Dunedin 9085, New Zealand;
e
Institute of Marine Science, University of Auckland, Auckland 1142, New Zealand; fSchool of Interdisciplinary Area Studies, University of Oxford,
Oxford OX2 6LH, United Kingdom; gAnthropology Programme, University of Waikato, Hamilton 3240, New Zealand; hDepartment of Management
and International Business, University of Auckland, Auckland 1142, New Zealand; and iSea Around Us, Global Fisheries Cluster, Institute for the
Oceans and Fisheries, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
Author contributions: E.S., G.S., S.M.D., G.B., S.F.T., H.W., F.M., B.C.R., N.H., P.J.C., D.P., and D.Z. wrote the paper.
The authors declare no conflict of interest.
1
To whom correspondence should be addressed. Email: liz.slooten@otago.ac.nz.

www.pnas.org/cgi/doi/10.1073/pnas.1706544114

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