At present laboratory reagent companies are suspending supply of specialised agar products due to low availability of raw material. These bacteriological/technical agars used in laboratories around the world are predominantly obtained from species of a single red algal genus, Gelidium. Harvesting of natural populations is the only source of feedstock as cultivation has never been feasible. Here we analyse historical landings data since the 1920s in all countries where natural Gelidium resources have been harvested. Up to WWII Japan was the only source of agar but then other countries like Spain, Portugal, Morocco, Mexico, and South Africa began to survey and exploit local Gelidium resources. Gelidium landings peaked in the 1960’s, while Japan lost market dominance. A sustained decrease in landings to less than 50% of peak annual values has occurred since. This trend was accompanied by concentration of feedstock production in just one country, Morocco, which contributed over 70% of world supply in the last two decades. A sudden decline in this country’s landings will have a disproportionate effect on world availability of Gelidium. This is actually the present situation when landing and export quotas were recently implemented in Morocco in order to safeguard the natural resources. Thus Gelidium agar is now undersupplied and priced itself out of the food industry but the increasing demand of bacteriological and technical agars will probably create an opportunity for historical producers, where production has declined, to get back into the market. If an interest in Gelidium resource exploitation is renewed adequate scientific management practices should be implemented. For this, simple harvest statistics such as daily harvest yields and harvest effort need to be collected by harvest area. Estimates of both the standing stock and the exploitation rate of the resource can then be calculated, without the need for time and space extensive, high cost sampling assessments.

1. Underwater Gelidium harvest off southwest Portugal - 1999

2. Back to basics
Global shortage of bacteriological
and technical agars
Ricardo Melo + Rui Santos

3. Nature 528: 171–172
(December 10th, 2015)
“Microbiology’s most important
reagent is in short supply, with
potential consequences for research,
public health and clinical labs around
the world.”
“already pushed wholesale prices of
agar to an all-time high of around
US$35–45 per kilogram — nearly
triple the price before scarcities
began.”
by Ewen Callaway
21/06/16 Melo + Santos 2
doi: 10.1038/528171a

4. • Gelidium
• Pterocladia/
Pterocladiella
• Gelidiella
• Gracilaria
Geography of commercial agarophytes
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5. Our ‘we told you so’ moment!
• ISS XIX – 2007, Japan – Global Gelidium resource
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0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
1980s 1990s 2000s
Decades
Landings(tdw)
South Africa
Chile
Mexico
Indonesia
Portugal
Japan
South Korea
Morocco
Spain

6. ISS XIX – 2007, Japan (cont.)
• Global Gelidium production in 3 preceding decades
• ≈ 16 000 t (dw)
• Stable in South Africa, Chile, Mexico, South Korea
• Collapsed in Indonesia, Portugal, Japan, Spain
• But, how sustainable this level of production?
• Maintained by Morocco’s very increased landings
• Representing 73% of world landings
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7. Our present objective is to:
• Compile available disseminated information
• More and better data communication
• Identify bottlenecks and sustainability problems
• Boost renewed attention to Gelidium resources
• Historical producer countries & others
• Disseminate a low cost stock assessment method
• Based on harvest effort statistics
• Effective use of harvest logbooks
• Coaching of harvesters for sustainability
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8. Mean decadal landings (t ww)
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9. Global Gelidium resource
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• Has been in decline since 1960’s peak
• Dramatic drop in the 2010’s
• Production less than 50% of peak value
• Business as usual?
2010’s mean harvest ≈
pre-WW II situation *
* 1940

10. Other take-home ideas
• Steady increase of Morocco’s global share
• From ≈20% in the 60’s up to ≈70% in the new century
• Global market virtually depends on sole
supplier
• Fluctuations should have DISPROPORTIONATE effect
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11. Case study: Morocco (1)
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12. Case study: Morocco (2)
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13. Morocco: updated management
• Gelidium harvest
• Interdiction: October 1st – June 30th
• Only beach cast harvest, no plucking, no night harvest
• In 2010 limit was 5440 t in 2010, 6040 t in 2014
• Traceability system for Gelidium and agar commerce
• Export licence regime for Gelidium and agar
• Restrictive export quotas enforced
• Only 20% of Gelidium production
• 80% must be processed in-country (Setexam, Kénitra)
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14. Santos, Cristo & Jesus 2003
• Describe stock assessment of Gelidium resource
based on harvest effort information
• Low cost compared with common standing stock
evaluations involving scientific diving
• Analysis of harvest effort data is highly informative
• But:
• Information on sea conditions for each harvest day must
be included to improve logbook data
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15. Gelidium corneum harvest in Portugal: yearly
variation of harvest yield, total harvest effort, and
seasonal CPUE (Santos et al. 2003)
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16. Training and coaching is a must
• Harvesters need to understand:
• How logbook data will be used
• The importance of providing accurate records
• Managers and scientists have to:
• Better communicate with harvesters
• Illustrate how the information obtained from harvest
effort data is to be used
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17. Gelidium corneum harvest in Portugal: yearly
variation of standing stock, harvest yield, exploitation
rate, and catchability (Santos et al. 2003)
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18. Data harvesting…
• A difficult task finding statistical data on agarophyte harvest!
• Also complicated assessing the quality of those data!
• On-line fisheries data from governmental and research
institutions, trade associations, international experts
• Many individual researchers and friends were of great help
Previous reports by Santelices (1988), Santos and Duarte (1991), Melo et al.
(1991), Melo (1998, 2002), McHugh (2003), and Santos et al. (2003) review harvest
methods, fisheries statistics, cultivation attempts, and stock assessment of
Gelidium species
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19. Thank you!
João Mariano – Photography
www.joaomariano.com
Antonieta Pedroso – Illustration
pantonieta@gmail.com