Aquacosm
Is Nutrient Deficiency the Reason for Quality Decrease in Turbot Fry Over the Season?
Jepsen, P. M.1*, Blanda, E.1, Jakobsen, H. H.2, Novac, A.3, Pedersen, A. T.4 & Hansen, B. W.1
1. Department of Environmental, Social, and Spatial Change, Roskilde University, 4000, Roskilde, Denmark2. Department of Bioscience, Aarhus University, 4000 Roskilde, Denmark3. Faculty of Biology, ”Alexandru Ioan Cuza” University of Iasi, 700507, Romania4. Maximus A/S, 7755, Bedsted Thy, Denmark
Background: A classical food chain was established, producing live feed for turbot larvae, in 3 replicate 280 m3 open top mesocosm tanks in three successive production cycles throughout May to September 2011 in Denmark 56°N.
Ph.d. studentPer M. [email protected] UniversityDenmark
Conclusion: Nutrient depletion controls the classical food chain and decreased the phyto- and zooplankton biomass, resulting in a reduced turbot larvae survival
This work was funded by IMPAQ grant (J. no. 10-093522) to Professor Benni W. Hansen, CommScie – POSDRU/89/1.5/S/63663 to Ph.D. Aliona Novac and Eliteforsk travel grant (J. no. 11-116388) to Ph.D. student Per M. Jepsen.
1
2
3
18%
12%
4%
3.5%
2.4%
9.6%
Survival DefectsProd. cycleproduction cycle 1
16/05 23/05 30/05 06/06 13/06 20/06
DIN
& S
i (µm
ol L
-1)
0
5
10
15
20
DIP
(µm
ol L
-1)
0,0
0,5
1,0
1,5
2,0
2,5
3,0Production cycle 1
23/05 30/05 06/06 13/06 20/06
Abu
ndan
ce [I
nd. L
-1]
0
100
200
300
400
Production cycle 2
23/07 27/07 31/07 04/08 08/08 12/08
Abu
ndan
ce [i
nd. L
-1]
0
100
200
300
400
Inorganic nutrients Phytoplankton biomass Copepod abundanceAdult L-1 Copepodite L-1 nauplii L-1 Eggs L-1
Production cycle 3
20/08 24/08 28/08 01/09 05/09
Abu
ndan
ce [I
nd L-1]
0
100
200
300
400
production cycle 2
date
25/07 29/07 02/08 06/08 10/08 14/08
DIN
& S
i (µm
ol L
-1)
0
5
10
15
20
DIP
(µm
ol L
-1)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
Water added to the tanks
production cycle 3
17/08 21/08 25/08 29/08 02/09
DIN
& S
i (µm
ol L
-1)
0
5
10
15
20
DIP
(µm
ol L
-1)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
Nutrients added to the tanks
16/5 23/5 30/5 6/6 13/6 20/6
µg C
hl a
0
5
10
15
20
25
Production cycle 1
25/7 1/8 8/8 15/8 22/8
µg C
hl a
0
5
10
15
20
25Production cycle 2
15/8 22/8 29/8 5/9 12/9 19/9
µg C
hl a
0
5
10
15
20
25Production cycle 3
date vs DIN DIPSi
greenDiatomCryptoBluegreen
Survival DefectsProd. cycle
Survival DefectsProd. cycle
Fish larvae characteristics
Acartia spp.
Centropages hamatus
Centropages hamatus
Acartia spp.
Acartia spp
Centropages hamatus
