aquacosm is nutrient d eficiency the reason for

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. Jepsenpmjepsen@ruc.dkRoskilde 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