Changes in the Biomass of Large Pelagic Predators
In a recent letter to Nature (423:280 - 283, May 15, 2003), Myers and Worm
present an analysis of catch and effort data from various trawl fisheries
and from the Japanese longline fishery for various ocean regions dating
back to the beginning of industrial fisheries exploitation. Their analysis
aggregates catch across species for each fishery type and interprets the
resulting aggregate CPUE as a time-series measure of "community biomass".
Rapid declines in CPUE during the 1950s and 1960s were observed, leading
the authors to conclude that "industrialized fisheries typically reduced
community biomass by 80% during the first 15 years of exploitation",
and that "large predatory fish biomass today is only about 10% of pre-industrial
levels". In the case of tuna fisheries, in particular the fisheries
for tropical tunas, many tuna experts contend that these conclusions are
fundamentally flawed. This web site hosts a number of critiques of this
paper as well as other interpretations of longline CPUE from various ocean
regions. The views presented below are those of the authors and do not reflect
the views of their employers or funders of their research.
The Letter to Nature letter can be obtained from the link below (subscription
or payment may be required): http://www.nature.com/nature/index.html
- May 3, 2005: An abbreviated critique by Hampton, Sibert, Kleiber, Maunder
and Harley (aka the Gang of Five) of the Myers and Worm (2003) paper on
changes in the CPUE of some fishes was published in Nature (434:E1-E2)
on 28 April 2005: Decline of Pacific tuna
populations exaggerated? Oddly, a "?" was appended to the
title after the proofs were returned. The "Nature-approved"
title appears to pose a question rather than make the intended statement.
More on the Gang's experience with Nature will appear on this site soon
...
- Dec. 14, 2006: John Sibert, John Hampton, Pierre Kleiber, and Mark Maunder
report status of 8 stocks of large predators, "Biomass,
Size, and Trophic Status of Top Predators in the Pacific Ocean" in
Science on December 15. Their major conclusion is that current
biomass ranges among species from 36 to 91% of the biomass predicted in
the absence of fishing. Supporting
online material
2009
- August 26, 2009. Things could be worse. Worm and his colleagues have
just published a new paper in Science
showing that fisheries might recover if we apply the principles of fishery
management. The paper also shows that, in regions where there are stock
assessments and surveys and well managed fisheries, fewer stocks collapse.
The paper itself and the voluminous supporting online material is curiously
silent about tuna, although several, presumably non-collapsed, tuna stocks
are included in the data. The paper notes that stock assessments and surveys
are rare in developing countries, but stops short of encouraging efforts
to develop stock assessment capabilities in developing countries.
Yawn ... lets hope this is the last posting on this site.
2008
2007
- Jan. 15, 2007: Distinguished Fisheries Oceanographer, Alan Longhurst,
sent this critique of Worm's
"Tunageddon 2048" paper to Science magazine. The editors of
Science informed Dr. Longhurst that they will not be publishing his critique
because that "have already received other Letters expressing similar
opinions".
2006
- January 2006: "Tuna longline
catch rates in the Indian Ocean: Did industrial fishing result in a 90%
rapid decline in the abundance of large predatory species", Tom
Polacheck, Marine Policy, 30 (2006) 470-482.
- January 27, 2006: "Crisis for Tuna Resources Triggered by Biased
Scientific Paper", by Dr. Yuji Uozumi of the National Research Institute
of Far Seas Fisheries, Fishery Research Agency, Japan, was recently published
by The Organization for the Promotion of Responsible Tuna Fisheries in
the January 2006 OPRT Newsletter. This paper is available at the OPRT
website, www.oprt.or.jp, under the Newsletter
International section.
- September 2006: The temptation to cross the line and abandon science
for advocacy is as strong as ever. Robyn Forrest and Tony Pitcher from
the University of British Columbia Fisheries Center published a devastating
critique of a Pew-endorsed junk science "analysis" of a fishery in Australia.
Although the subject matter is not explicitly large predators, the theme
of the critique is highly relevant to the material on this site, and the
recommendation in the final paragraph is particularly apt.
Robyn Forrest and Tony J Pitcher (2006). Misguided
Claims of Overfishing in New South Wales: Comment on "Empty Oceans Empty
Nets. An evaluation of NSW fisheries catch statistics from 1940 to 2000"
Fisheries Centre Working Paper #2006-16, The University of British Columbia,
Vancouver, B.C., Canada. This working paper can also be obtained from
http://www.fisheries.ubc.ca/publications/working/
- September 2006: Interpreting
catch per unit effort data to assess the status of individual stocks and
communities. Mark N. Maunder, John R. Sibert, Alain Fonteneau, John
Hampton, Pierre Kleiber, and Shelton J. Harley. ICES Journal of Marine
Science, 63: 1373-1385 (2006).
- September 2006: Watch Ray Hilborn address the new "litany" of fisheries
management in a University of Washington Science Forum talk entitled "Re-interpreting
the fisheries crisis".
- November 2006: Tunageddon 2048. A recent article by Boris Worm and
colleagues in Science magazine quot;Impacts of Biodiversity Loss
on Ocean Ecosystem Services" Science 314:787 (2006) contains
a silly extrapolation predicting the end of the world as we know it in
2048. John Tierney, in an Op-Ed paean to ITQs in the New York Times, dubbed
this prediction "the Tunageddon of 2048". Similar
predictions have not fared well.
- Dec. 14, 2006: John Sibert, John Hampton, Pierre Kleiber, and Mark
Maunder report status of 8 stocks of large predators, "Biomass,
Size, and Trophic Status of Top Predators in the Pacific Ocean" in
Science on December 15. Their major conclusion is that current
biomass ranges among species from 36 to 91% of the biomass predicted in
the absence of fishing. Supporting
online material
- Dec. 18, 2006: Ray Hilborn weighs in on the rash of poorly supported
papers appearing in the science tabloids in an essay entitled "Faith-based
Fisheries" published in Fisheries 31(11):554-555, 2006.
2005
- March 2005: Are pelagic fisheries managed well?
A stock-assesssment scientist's perspective. PowerPoint Presentation
at the Fifth William R. Lenore Mote International Symposium, The good,
the bad, and the ugly: integrating marine and human ecology into fisheries
management, Sarasota, Florida, November, 9-11, 2004. Mark N. Maunder and
Shelton J. Harley. (PPT, 1.9 MB)
This presentation contains additional information on the "notes"
page. After opening the file with PowerPoint, please select "Notes
Page" from the "View menu". PDF version of the presentation
(639 KB) and Notes (922 KB).
- March 2005: Evaluating tuna management
in the Eastern Pacific Ocean. Mark N. Maunder and Shelton J. Harley,
Bulletin of Marine Science 78(3): 593606, 2006 (PDF 136 KB).
- April 2005: Those interested in the development of the global tuna
industry would do well to consult the recent publication by Peter Miyake,
Naozumi Miyabe and Hideki Nakano entitled "Historical trends of tuna
catches in the world", FAO Fisheries Technical Paper No. 467, Rome,
FAO. 2004. 74p. It can be found on-line in html format at:
http://www.fao.org/documents/show_cdr.asp?url_file=/docrep/007/y5428e/y5428e00.htm
and in pdf format at ftp://ftp.fao.org/docrep/fao/007/y5428e/y5428e00.pdf
- May 24, 2005: "Counting
Tuna", KPBS San Diego radio interview with Mark Maunder, Senior
Scientist with the Inter-American Tropical Tuna Commission, I-ATTC.
- October 2005: Reports of drastic decreases in abundance have provoked
controversy similar to the controversy over changes in tuna abundance.
Two papers in particular have generated a heated debate in the journal
Fisheries. These papers can be obtained from the link belows (subscription
or payment may be required):
Baum, J. K., R. A. Myers, D. G. Kehler, B. Worm, S. J. Harley, and P.A.
Doherty. 2003. Collapse and Conservation of Shark Populations in the Northwest
Atlantic, Science 199: 389-392.
http://www.sciencemag.org/cgi/content/full/299/5605/389
Baum, J. K., and R. A. Myers. 2004. Shifting baselines and the decline
of pelagic sharks in the Gulf of Mexico. Ecology Letters 7:135-145,
Issue 2, Page 81-163.
http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1461-0248.2003.00564.x
Critique from George Burgess and colleagues: Is
the collapse of shark populations in the Northwest Atlantic Ocean and
Gulf of Mexico real?
Response from J. K. Baum and colleagues: Robust
estimates of decline for pelagic shark populations in the northwest Atlantic
and Gulf of Mexico
Reply from Burgess et al: Reply to Robust
estimates of decline for pelagic shark populations in the Northwest Atlantic
and Gulf of Mexico
Mercifully, the editors of Fisheries declined to prolong the agony
at this point.
2004
- Feb. 2004: Nature Stumbles (PDF, 79 KB) by
Menachem Ben-Yami, World Fishing, 2003(8):10. Comments and questions
to Menakhem Ben-Yami, benyami@actcom.net.il.
Related commentary by Ben-Yami can be found at http://sharpgary.org/MBYINK.html
- May 2004: Problems with interpreting catch-per-unit-of-effort
data to assess the status of individual stocks and communities: Is integrated
stock assessment, ecosystem modeling, management strategy evaluation,
or adaptive management the solution? (PPT, 1.7 MB) PowerPoint presentation
to the Fourth World Fisheries Congress, Vancouver, BC, Canada, May 2-6,
2004, Mark N. Maunder, John R. Sibert, Alain Fonteneau, John Hampton,
Pierre Kleiber, and Shelton J. Harley. (PDF version
and additional notes)
2003
- June 2003: Critique from Hampton, Sibert
and Kleiber (PDF, 346 KB). Send comments or questions to: John Hampton
JohnH@spc.int, John Sibert sibert@hawaii.edu,
Pierre Kleiber pkleiber@honlab.nmfs.hawaii.edu
- June 2003: The editors of Nature declined to print the following letter
because it does not "take our knowledge forward in some discernible
way". The signers of this letter have the same opinion of the Myers
and Worm letter. Letter to the
Editors of Nature (PDF, 10 KB)
- June 2003: The following letter was sent to U.S. Senator John McCain
of the Senate Committee on Commerce, Science and Transportation on the
occasion of June 12, 2003. Letter
to Senator John McCain
The record of the Commerce Committee hearing can be viewed at:
http://commerce.senate.gov/hearings/witnesslist.cfm?id=808
- June 2003: Can biomass time series be reliably
assessed from CPUE time series data only? (PDF 189 KB). Send comments
or questions to: Francis Laloë, laloe@mpl.ird.fr
- July 2003: Ecosimple: A new individual based model tool for
application to ecosystem-based fishery management. It includes real-time
management intervention from the user, effects of research, marine reserves,
habitat, realistic graphics, and sound effects, and it operates from the
perspective of the fish. Anyone who succeeds in maintaining a balanced
ecosystem should contact the PFRP and convey the text of the verification
message. It may confer eligibility to publish in Nature. Development of
this software was not supported by the Pew Charitable Trust or by anyone
else we can get to admit to it.
Ecosimple Read Me file (PDF), Ecosimple.exe
file (1.3 MB)
- We are not alone. Nature declined to print a critique of an
article on the impacts of aquaculture on wild fisheries. The critique
was eventually published in the report of the ICES Working Group on Environmental
Interactions of Mariculture. The associated web site is of interest: http://ciencia.silvert.org/eim/response/index.html
- September 2003: Tuna Longline Catch Rates in
the Indian Ocean (PDF, 212 KB). Send comments and questions to: Tom
Polacheck, tom.polacheck@csiro.au
- December 2003: Are the Apparent Rapid Declines
in Top Pelagic Predators Real? (PPT, 1.6 MB). PowerPoint presentation
to the Scripps Institution of Oceanography Ecology Seminar, March 12,
2003, Mark Maunder, Shelton Harley, Mike Hinton et al. (PDF
version, 679 KB)
- 2003: Folly
and fantasy in the analysis of spatial catch rate data (PDF, 131 KB).
Carl Walters, Can. J. Fish. Aquat. Sci./J. Can. Sci. Halieut. Aquat. 60(12):
1433-1436 (2003).
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