Dynamic and Ecological Role of Mussel Farms in a Mediterranean Coastal Area Solidoro C., Beran, A., Cabrini M., Cummaudo F., Del Negro P., De Vittor C., Fornasaro D., Guardiani B., Libralato S., Lipizer M., Minocci M., Monti M. Istituto Nazionale di Oceangrafia e di Geofisica Sperimentale - OGS Dept. Oceanography & Dept. Biology Trieste, Italy INTERREG III - ECOMADR Project Endorsed by
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Dynamic and Ecological Role of Mussel Farms in a Mediterranean Coastal Area
Solidoro C., Beran, A., Cabrini M., Cummaudo F., Del Negro P.,De Vittor C., Fornasaro D., Guardiani B., Libralato S., Lipizer M., Minocci M., Monti M.
Istituto Nazionale di Oceangrafia e di Geofisica Sperimentale - OGSDept. Oceanography & Dept. BiologyTrieste, Italy
INTERREG III - ECOMADR Project
Endorsed by
Mussel farming in the Gulf of TriestePart of the ECOMADR project (1.5 y; Scientific Coordinator: Cosimo Solidoro) was dedicated to a preliminary study of dynamics and role of mussel farms in the Gulf of Trieste (North Adriatic Sea, Italy):
approx. 200’000 m of ropes, 4’000’000 m2 of surface; potential prod. 8’000 ton/year; value 1.6 million €/year
Adriatic Sea
MediterraneanSea
Issues and problems:1- impacts on water & sediments quality;2- trophic interaction with other marine resources (small pelagics?);3- yearly fluctuation of production;
Issues, aims and methods
Biogeochemical measurements in water & sediment inside the farm and in the reference station (DOC, POC, nutrients, Chl-a, Pheo, LOM, etc)
1- impacts
2- trophic interactions
Qualitative evaluation of mussel diet(gut content)+ Plankton populationsin farm’s water and reference station
3- performance production
Growth measurements (2 coorts x 1 year)+ bioenergetic model of mussel
ECOMADR Project
1- Impacts of mussel farms on water quality
Chl-a and Pheosystematicallylower in musselfarm than inreference site:effect ofmussels’ grazing
0
0.5
1
1.5
2
2.5
3
Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07
µg l-1
Chlorophyll
Pheopigments
Reference site (T21)
Mussel farm (M3)
M3(mussel farm)
T21(reference site)
Dissolved and Particulated OrganicCarbon are generally higher in the mariculture site
1- Impacts of mussel farms on water quality
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07
mg
l-1
DOCPOC Reference Mussel farm
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07
µM
N-NO2
P-PO4
Reference
Mussel farm
0
0.5
1
1.5
2
2.5
3
3.5
Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07
µM l-1
N-NH4N-NO3
Reference
Mussel farm
In december 2006 the lower DOC in mussel farm is accompanied bya higher concentration ofnutrients, i.e. phosphates, nitritesand ammonia): higher degradation rate in mussel farm
In general the data show animpact of mussel farm on waterquality parameters
Sediments show a general higher content of Biopolymeric carbon (also LOM) in the mariculture site
2- Trophic interactions: effects on plankton communities
M3(mussel farm)
T21(reference site)
Abundance of phyto and microplankton species evauated in the 4 samples(sept06, dec06, feb07, may07) in water samples collected inmussel farm (M3), inreference site (T21).
0%
5%
10%
15%
20%
25%
30%
35%
0% 5% 10% 15% 20% 25% 30% 35%
Relative abundance in Reference site (T21)
Rel
ativ
e ab
unda
nce
in m
usse
l far
m (M
3)
Is this a direct effect of mussel selective filtration?
1:1 line
Phytoplankton speciesabundance
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
0.0% 20.0% 40.0% 60.0% 80.0% 100.0%
Relative abundance in water (M3)
Rel
ativ
e ab
unda
nce
in M
ytilu
s
_
2- Mussel selectivity of plankton species
Indifferentspecies
Sele
cted
spe
cies
Rejected species
Comparison of the relative abundance of phyto and microplankton species in waterfrom mussel farm (M3) and in gut of mussel (50 each season) should evidence selectivity of mussels on each plankton species (phyto & micro).
3- Production performances: mussel growth Experimental measure of growth:monthly biometric measurements on 2cohorts displaced in a dedicated area of a mussel farm (M3).50 individuals each month for each cohort
Calibration parameter:Maximum clearence rate (CRmax) and fraction into gonads (γ).
Forcing:TSMPOMChlorophyllTemperature(local data)
The model runs on length,wet and dry weight basis by using allometric scaling factors.
Bootstrap allowed obtaining distribution of estimated parameters (Crmax, γ).
Spawning periods
3- Annual flows associated to mussel farms
ANABOLISM
Feces
FILTRATION
Pseudofeces
consumo energia
INGESTION
ABSORPTION
650 tonC (1,18 1010 kJ)
TOTAL WEIGHT mussels
356 tonC (6,46 109 kJ)
Energy consumption
294 tonC (5,34 109 kJ)
3220 tonC (4,48 1012 L)
1880 tonC
RESPIRATIONGROWTH GONADS
Energy investment
6124 ton ww
Energy intake SESTON(TPM)
1340 tonC
1230 tonC
Montecarlo:virtual population of theGulf of Trieste composed by different individuals(different Crmax and γ).Realistic seeding time (Sept) and differential harvesting (from May to Sept).
Annual flows for all the mussel farms of the Gulf of Trieste
The mussel farmed in the Gulf of Trieste derivedirectly from phytoplankton
104 tonC/year of the 3220 tonC/year filtered
3- Annual flows associated to mussel farms
Average Primary Production of the GoT:
42-53 gC m-2 year-1
(Fonda Umani et al., 1992)
Assuming area of influenceof 1 km from the coast:Total Primary Productionapproximately1160-1460 tonC year-1
Mussel farms consumeSlightly less than 10% of this production
Conclusions
ECOMADR Project
Mussel farming impacts on water quality:drecrease of Chl-a and Pheo, increaseDOM, modify degradation of OM in someperiods (see december 06)
Mussel farming produces increase of LOM in bottom sediments
Mussels are selective filter feeders: inducemodification on plankton communities but we need lab experiments for soft species(non detecteable in guts)
We set up a model that reasonably represent mussel growth on the basis of water column data (POM, TPM, Chl-a, T)
About 10% of the Primary Production of the Gulf of Trieste is estimated to be consumed by mussels
All this need to be studied deeperand linked together: in the next
project (starting Jan08)!
Thanks!
Istituto Nazionale di Oceangrafia e di Geofisica Sperimentale - OGSDept. Oceanography & Dept. BiologyTrieste, Italy