Bivalves : Success in a Shell

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Bivalves Success in a Shell

• Douglas McLeod
• Chairman, Association of Scottish Shellfish
  Growers

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World bivalves production 1970-2005
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World bivalves aquaculture prodn. 1970-2005
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World bivalves aquaculture production 1970-2005
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World bivalves aquaculture production, 2005
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Share of aquaculture and capture by species, 2005
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Drivers

• Drivers behind the global expansion include
• - Recognition of the efficiency of
  filter-feeding bivalves in converting
  phytoplankton nutrients into nutritious and
  high quality animal protein
• - Relatively low capital access
  requirements
• - Frequently a natural, low cost source of
  seed
• - Absence of feed costs for on-growing
• - Relative ease of transport.

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Drivers (2)

• At a strategic level
• - Contribution to domestic nutrition (cf
  export cash crops of high value finfish
  crustaceans).
• - Acknowledgement of the minimal
  environmental impact of bivalve aquaculture

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World mussel exports by product form, 1976-2004
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World exports of clams by product form, 1976-2004
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World scallop exports by product form, Q,
1976-2004
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World oyster exports by product form, 1976-2004
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Exporting

• Limited volumes involved 2005 (estimates)
• Mussels 275 mt (16 of aquaculture prodn)
• Scallops 80 mt (6)
• Clams 80 mt (1.9)
• Oysters 60 mt (1.3)
• Total c. 500 mt

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Breaking into international trade

• Requires a combination of critical factors
• - Availability of excess product
• - Competitive pricing and transport systems
• - Farmers organisations and/or trade
  associations to offset small scale operators
• - Access to agents in target markets

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Chilean Aquaculture - Global Context

• Chile within the top ten aquaculture producers
  worldwide.
• Country population 14 million ,
• 68.703 employed in the sector

• US 1.8 billion dollars (FOB) aquaculture
  export (2005).
• Aquaculture more than 60 of fishery sector
  export (4.2 of GDP)
• 25 increase vs past year (record).
• Challenge of cost, competitiveness in the
  international markets.

Sernapesca, 2005
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Mussel Chilean production
95 exports
In 2005 total production 95.000 MT ( mainly
frozen).
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Frozen IQF
Pasteurized, 40-60 u. per bag 2 pounds
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Dic 2005 254 ton (2006) 350 ton expected
Source Chilean Customs
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Source Chilean Customs, 2006IFOP, 2006
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Envíos de abalón a principales mercados Source
Aduana, 2006
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New Zealand - Low population (4 Million)-
Limited domestic consumption- Unpolluted waters
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Oyster cultivation Natural seed supplyRapid
growth cycle
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High growth rate for suspended mussel culture in
Marlborough Sounds
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Expansion in sites/leases
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New Zealand

• 1990 2005
• - Greenshell Mussel production more than
  trebled from 24,000 Tonnes (T) to 85,000 T
• - Exports rose from 6,330 Tonnes to 35,000 T
  (from 26 to gt40 of production)

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Geography dictates exports in processed form
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Distribution on a global basis
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New Zealand (2)

• 1990 2005
• - Oysters (C. gigas) production rose from
• 1,500 T to gt2,500 T
• - Exports increased from 1,300 T to gt2,000 T
  (around 80 of production)

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While in China .

• Production increased from lt 2 MMT in 1990 to 9.5
  MMT in 2005
• Over the same period, exports rose from 5,250 T
  to 46,500 T
• - From 0.2 to 0.5
• China absorbs its domestically produced molluscs
  (and imported gt6,000 T in 2005)
• Will this situation continue? Or is there an
  avalanche of molluscs about to impact upon world
  trade? Or will China expand its imports to
  satisfy domestic demand?

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While in China .

• Production increased from lt 2 MMT in 1990 to 9.5
  MMT in 2005
• Over the same period, exports rose from 5,250 T
  to 46,500 T
• - From 0.2 to 0.5
• China absorbs its domestically produced molluscs
  (and imported gt6,000 T in 2005)
• Will this situation continue? Or is there an
  avalanche of molluscs about to impact upon world
  trade? Or will China expand its imports to
  satisfy domestic demand?

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? ? PRODUCTS
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• ??????
• Main Cultivation Product

???? Abalone
???? Hokkaido Scallop
?? Sea Cucumber
??? Purple Sea Urchin
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?????? Main Cultivation Product
??? Sea Squirt
?????? Strongylocentrotus Intermedius
?? Conch
?? Ark Shell
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?????? Main Processing Product
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Regulatory criteria

• International standards
• - Biotoxins
• - Microbiology
• - Heavy metals
• On-going debate over relevance, accuracy and
  appropriateness
• Protection of consumers, or non-tariff barriers?

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Mouse bioassays for PSP and DSP toxins

• The standard method for biotoxin monitoring is
  the Mouse Bioassay (MBA)
• Claim the MBA is a robust, reliable method
  for the detection of PSP and DSP toxins

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Mouse Bioassay for PSP

• Has been used for over 50 years
• Intraperitoneal (ip) injection of 0.1M HCl
  extract of shellfish tissues into 20 g mouse
• Measure time to death one mouse unit amount
  that kills in 15 min
• Advantage A single number corresponds to
  overall toxicity of sample expressed as µg STX
  equiv/kg tissue

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Mouse Bioassay for PSP - Disadvantages

• Detection limit (400 µg/kg) near regulatory
  limit (800)
• Poor precision ( 20-30)
• Salt suppression effects - poor accuracy at low
  levels
• Subject to false positives (e.g., zinc in
  oysters)
• Ethical concerns (test has been banned in some
  countries)

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Mouse Bioassay for DSP - Disadvantages

• Selectivity of assay dependent on choice of
  solvent used for extraction
• Substantial animal suffering requires many
  mice
• False negatives and false positives occur
• Not fit for purpose - namely to detect OA, PTX,
  YTX and AZA
• Not developed for routine monitoring to protect
  against DSP
• Relationship between i.p injection in mice and
  oral toxicity in humans differs for some
  lipophilic toxins
• Cyclic imines and spirolides (not regulated in
  the EU) are detected
• Effects of combinations of toxins are unknown
• DSP MBA is still not harmonised in the EU
• Differences between strain and sex of mice
• No formal validation

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Mouse bioassays for PSP and DSP toxins

• The mouse bioassay is a robust, reliable method
  for the detection of PSP and DSP toxins

FICTION
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Reduction, Refinement, Replacement

• Research to progress 3Rs in shellfish toxin
  monitoring (Directive 86/609/EEC)
• MIST AlertTM/Jellet Rapid Test (JRT) Reduction
  of PSP bioassay
• Anaesthesia for MBA Refinement of PSP bioassay
• HPLC-FLD (pre-column) Replacement of PSP
  bioassay
• LC-MS Replacement of DSP bioassay

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Microbiology

• Use of E.coli as indicator for microbiological
  pollution raises concerns
• Need to move to appropriate indicator, or direct
  viral monitoring (the critical problem)
• Need to reflect realities rather than established
  scientific assumptions

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Modern efficient treatment reduces the bacterial
load in urban areas
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In remote areas livestock /or wild animals
generate high E.coli loadings but low viral
loading so low risk to human health
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Microbiology (2)

• By using E.coli as an indicator, there is a
  correlation between remoteness and perceived
  pollution!
• In my country, Scotland, the only areas with C
  results are the isolated wild areas
• Yet the risk to human health from deer, sheep,
  seals, seagulls and eider ducks is minimal
• This clearly requires change.

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Microbiology (2)

• The future growth of the molluscan sector in
  rural areas depends upon implementation of a more
  appropriate measure, reflecting the lower risk to
  consumers
• Based on demographics (population/hectare)
• Managed on diffuse pollution events, eg catchment
  rainfall or salinity changes
• Management on the basis of credible risk
  assessment

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Market Values

• Not discussed pricing or profitability
• Prices are a statistical quicksand, varying
  according to many criteria fresh, frozen, size,
  meat yield, specifications, presentation,
  farmgate, wholesale, retail, exchange rates, etc.
• Pier head values for mussels Chile US100
• New Zealand US580 Ireland dredged US530
• Scottish suspended US1,990 China ??

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Conclusions (1)

• Great opportunities remain for expansion in
  international trade in molluscs
• Fit for purpose regulation essential,
  reflecting requirements of relevant export market
  (eg Japan, EU, USA) but importing Regs must be
  credible, not acting as non-tariff barriers
• Regulation (in all countries) to protect consumer
  health is an essential service, but must be
  appropriate in method, accuracy, scope and
  frequency
• Risk assessment and management should be
  highlighted as the regulatory approach

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Conclusions (2)

• Changes in the regulatory regime are urgently
  required
• In biotoxin management, the move to chemical
  methods and away from MBA should be promoted
  strongly
• In microbiological management, new methods are
  required for rural areas
• Communication engagement with industry should
  be priorities not afterthoughts

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Conclusions (3)

• Must avoid excessive scientific focus on novel
  toxins, hyper-accuracy and lower Levels of
  Detection in methods
• Multi-lateral/international collaboration
  essential

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