Oyster farming in the Ligurian Sea an Integrated

Oyster farming in the Ligurian Sea
an Integrated Multitrophic Aquaculture (IMTA) approach
Danilo Pecorino1, Luca Fanciulli2, Roberto Cò2, Mariachiara Chiantore1
1
2
DISTAV, University of Genoa, C.so Europa 26, 16143 Genoa, Italy
Aqua Srl, 129 Calata Porto Turistico, 16033 Lavagna (GE), Italy
Oyster farming is a commercial activity for which medium to high concentrations of nutrients and phytoplankton are
required, in order to satisfy the nutritional needs of the farmed organisms and produce commercially attractive
products.
These conditions are rarely met in the Ligurian Sea, characterized by oligotrophic conditions. To overcome this limit,
a novel approach, which involves farming of filter feeders downstream finfish cages, was adopted.
This research was part of the project FP7 IDREEM, on integrated multitrophic aquaculture (IMTA)
On the left, a schematic of the
experimental set-up at AQUA farm
in Liguria, with oyster lanterns
downstream the finfish cages, in
order to receive the particulate
matter falling off the cages. Oysters
were placed at 7 and 14 m depth to
test for an effect of depth in allowing
for a higher feed availability and
growth. This experiment lasted from
June 2013 to May 2014. Shell length,
whole wet weight, % of soft parts
and mortality were monitored in
November 2013 and May 2014.
Ostrea edulis
Crassostrea gigas
Ostrea edulis
Ostrea edulis
May14–14m
May14–7m
May14–14m
May14–7m
Nov13–14m
Nov13–7m
May14–14m
May14–7m
Nov13–14m
Nov13–14m
May14–14m
May14–7m
Nov13–14m
Nov13–7m
May14–14m
May14–7m
0
Nov13–14m
2
Nov13–7m
4
May14–14m
6
May14–7m
8
Nov13–14m
Mortality % ± SD
10
Crassostrea gigas
9
8
7
6
5
4
3
2
1
0
Nov13–7m
12
Nov13–7m
Soft part (% total body WW) ± SD
Ostrea edulis
Nov13–7m
Jun13
May14–14m
May14–7m
Jun13
0
Nov13–14m
20
Jun13
40
Nov13–14m
60
Nov13–7m
80
90
80
70
60
50
40
30
20
10
0
Jun13
100
Whole Wet Weight (g) ± SE
120
Nov13–7m
Shell Lenght (mm) ± SE
On the left, average shell length (mm)
(n=100), and, on the right, average
whole wet weight (n=100) of O. edulis
and C. gigas farmed at two depth
treatments from June 2013 to May
2014.
EMAIL info@idreem.eu
On the right, a photo of the two
shallower oyster lanterns.
photo by Luca Fanciulli
May14–14m
WEB
Oyster
lanterns
May14–7m
www.idreem.eu
Finfish cages
Crassostrea gigas
On the left, average percentage
contribution of the soft edible parts
to the whole weight (n=10), and on
the right, average percentage
mortality (n=100) of O. edulis and C.
gigas farmed at two depth treatments
from June 2013 to May 2014.
Crassostrea gigas
Both oyster species reached a legal size for commercialization (60 mm, Italian law 963/1965 and DPR 1639/1968)
during the 12 months farming trial.
Their weight placed them both in the medium commercial size class 3 (66-85 g), which sales at a market price of
≈9.60 € for O. edulis and ≈2.50 € for C. gigas.
This study, therefore, supports the hypothesis that oysters can be farmed in the oligotrophic Ligurian Sea and
profitably grown to a commercial size by using IMTA techniques based on finfish effluents.
The potential for a reduction of the impact by farm effluents is present.
What’s next: second experiment with oysters both upstream and downstream the cages
get water classification for commercialization of oysters (presently liasing with relevant authorities)
The research leading to these results has been undertaken as part of the IDREEM project (www.idreem.eu) and has received funding from the European Union's Seventh Framework
Programme (FP7/2007-2013) under grant agreement n° 308571.