Transcript Restoration of oyster production in France by introduction of non

HEGARET Hélène
UCONN, Department of Marine Sciences,
1080 Shennecossett Road, GROTON, CT 06340, US
MAZURIE Joseph
IFREMER, Station de La Trinité Sur Mer,
12 rue des Résistants, BP 86, 56470 La Trinité Sur Mer, France
Restoration of oyster production in
France by introduction of non-native
species : history and overview
J.Barret, A.Gerard, P.Goulletquer, JP Baud
acknowledged for documents
Historic (1) – Beginning of oyster
farming
European flat oyster, Ostrea edulis,
harvested for several centuries.
1850 -
First Ostrea edulis farming in France
1868 -
Introduction of the Portuguese cupped
oyster, Crassostrea angulata, into
the Gironde estuary
1970 -
C. angulata and O. edulis on the
French coast
Historic (2) – Introduction
of Crassostrea gigas
• 1966 and 1969: First “Non-official” introduction of the
Pacific oyster from Japan, into the Marennes-Oleron and
Arcachon basins ;
=> excellent survival & growth performance
• 1971-1977: official, controlled introduction of
500mt of broodstock oysters from Canada and
>5 billion spat from Japan, to Arcachon and Marennes.
Historic (3) – Virus and parasites
Cupped oyster
Flat oyster
1966, 69- C.gigas :
first introduction
1970-73 - C. angulata :
Viral infection
(iridovirus)
1979 2000 -
Protozoan parasite,
Marteilia refringens :
Marteilia refringens spp.
Source : Ifremer/drv/lgp
production of O. edulis :
=> total loss
(20,000 to 10,000t)
C.gigas
Protozoan parasite,
substitution
Bonamia ostreae :
and development
production
2,000t per year
(10 M€).
Bonamia ostreae
Source : Ifremer/drv/lgp
French oyster production in the
last century
150 000 t
C. gigas
100 000 t
C. angulata
50 000 t
O. edulis
1900
10
20
30
40
50
60
70
80
90
2000
Graphiques: J.Barret
O. edulis farming today
• Attemps to eradicate
M. refringens: unsuccessful !
Photo Dao
• No more farming in closed Bays and Estuaries
(more sensitive to Marteilia development)
• New development in open Bays (Cancale, Quiberon) :
low densities of seed (1 million per ha)
no manipulations between seeding and harvest
• Resistant strain to B. ostreae developed and tested
experimentally (validation trial in the field now).
O. edulis farming today
2 000 t
10 M€
Bretagne
80%
Only in deep waters
since 1970 because of
the 2 epizootics
18000
Marteilia
refringens
16000
14000
Languedoc
Roussillon
12000
Bonamia
ostreæ
10000
8000
20%
6000
4000
2000
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90
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60
0
Graphiques: J.Barret
The success of C. gigas
(replacement of C.angulata …and more)
• Since 1975, natural reproduction
Successful
& spat collection
=> No need for further importations
• Resists endemic parasites in French
growing areas => replaces its “relative”
C.angulata
• Expansion northward (supplants the
declining O.edulis in Brittany)
Genetics of C. gigas and C. angulata
Introduction from Japan
since the beginning of the
70s (C. gigas)
ARCACHON
SEUDRE
BREST
COREE
OUALIDIA
VENISE
BANGOR
Introduction from Asia in
the 15th centuary with
portuguese fishermen
TAHADDAR
(C. angulata)
T
TAIWAN
FARO
CADIX
SETUBAL
Source Ifremer : Boudry el al.
C.gigas : diverse sites and a variety of
22.5 %
culture techniques
135 000 t
220 M€
30.3 %
Basse
Normandie
Bretagne
• Principally on the
Atlantic coast, in
open, intertidal parcs
Pays de
Loire
7.5 %
Poitou
Charente
22.5 %
Aquitaine
0.1 %
8.3 %
Languedoc
Roussillon
• On the Mediterranean
coast, in natural semiclosed lagoons (subtidal)
Corse
8.85 %
Graphiques: J.Barret
On the Atlantic side : Coasts with tides
On the bottom
• Traditionnally
(before 1970)
• Culture on the
bottom after
seeding
On « tables »
Since 1970
• On « tables »
• in bags («poches »)
• elevated 50-70 cm
above surface
• 1 to 3 years of growth
In deep waters
Coasts without tides :
Mediterranean coast (Thau lagoon mainly)
In suspension under racks
(« tables »)
Bay of Mont-St-Michel :
First Breton shellfish culture site
• Moderate local productivity, but high
exchanges (15 m tides ...)
• Low runoff influence
• Diversity of bivalves
both natural (clams, cockles…) and
cultivated (flat and cupped oysters,
mussels…)
• Competition with a filter-feeding
invader (150,000 mt of Crepidula)
Rade de Brest : urbanised ...
low production of
mussels and oysters,
but first success in
Pecten maximus aquaculture
Quiberon Bay (South Brittany)
Deep water bottom oyster farming (15,000 mt).
Seeded from oyster dredgers, harvested with dredges.
Morbihan Golfe (Brittany)
confrontation between shellfish culture and other activities
Marennes-Oléron Basin :
Limits to development of oyster farming?
• Trophic Capacity limits
(sustitution sites)
• Restriction through recent
management plans
(SMVM, Natura 2000),
water quality standards
Finishing - « affinage »
• Few weeks to a few months
of « affinage » in claires.
S. Costatum
Haslea Ostrearia
•Technique leading to official
quality labels
« fines et spéciales de claire »
• Diatoms responsibles for
the greening of the gills
Arcachon Basin
Long tradition of
oyster farming
Pollution problems
(TBT…)
Competition with high
tourist pressure
THAU lagune : a shellfish culture « pond »
• Exceptionnally
productive (commercial
size within 1 year)
• fragile (eutrophication,
contamination…)
• But highly protected
(prevention of sewage
from the drainage basin)
Source : Chaussade et Corlay
There is no such thing as an
unqualified success!
Associated flora and fauna
(nuisances or not)
•
•
•
•
•
•
•
Balanus amphitrite and B. albicostatus (cirripeds)
Hydroides enzoensi (annelid)
Aiptasia pulchella (cnidarian)
Anomia chinensis (mollusc)
Undaria pinnatifida (alga)
Laminaria japonica (alga)
…
Regulations / Recommandations
for planned introductions
• ICES code of practice
(Copenhagen 1994)
• Federation of European Producers (FEAP) code of
conduct
Assure a high standard of quality food production while
respecting environmental considerations and consumer demands
Recent summer mortalities
• Essentially during the first summer
Can reach up to 50%
140
% 3N/2N
135
130
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120
Management options:
• Changes in culture practices
N
• Selection of resistant strains
• Development of sterile (and fast growing)
triploid oysters
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110
Port-enBessin
Marennes
Oléron
Arcachon
Thau
Ifremer REGEMO
S
The French experience summarized
A risky success story
• C. gigas introduced where cupped (portugese) oyster
farming existed : Arcachon and Marennes
• Northern expansion following collapse of flat oyster
(Brittany): amenable to aquaculture, and high demand!
• However, C. gigas remains an introduced species
=> eventual mis-adaptations (mortalities)
=> a few undesirable by-species
All the “oysters” in one basket !
Thanks
Elaine Knight
Rick DeVoe
Dorothy Leonard
And the all organization committee of the
International Conference on Shellfish Restoration