Secondary Production of Owenia fusiformis
267
Station 14 (3m)
775
July 1996
200
TA= 1492
150
100
50
0
Station 304 (8m)
July 1996
TA=13717
150
100
50
....... ,
0
Station 1014 (12m)
July 1996
TA=629
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
f
O~1996
) 100
TA=333
~ l I
~ 50
I I
.~ 0 +-~. ---,---,0,-",. ..... ~. ,-.. •• -..,. . .
.,.., ....... ~ ... -,.. ~, ~. -r--,. ,
Oct 1996
TA= 5429
,.,-,
Oct 1996
TA=221
150 1
100
I
50
•
I.
o~,--,-~, ~.~.~,~,~~--,-r-r~,-,~,~
-g 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.1 0.9 1.1 1.3 1.5 1.7 1.9
::.
II)
Feb 1997
Feb 1997
u
~=n
~=N
j ~ 1 ,
.~-. , ,-,-,-, ~~ +l-,-r-r--r-o~~-,-.,-,.-.-..-r--,-,.--,--,
§
01 03 05 07 09 11 13 15 11 19
0103 05 07 09 1113 15 17
~
May 1997
~+l~,~r-r~~~~,-.~~~,!~~--=~. ~58~
5~1, ,_
-,.,.
July 1997
TA=54
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
1000 1
May 1997
50: +_ ~,......~~, ••• ,..I,JIII,I.I-; • .,..\11 ...... , T.~A~~_~4.,..,B'"r~....,
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
5~ 1 , , . , , , , . , .. ,
July 1997
TA=25
0.1 0.3 0.5 0.7 0..9 1.1 1.3 1.5 1.7 1.9
Width of first abdominal segment (mm)
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
~ 1 . ,.,Feb 1997
TA=29
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
Fig. 4. Seasonal distribution of O. fusiformis size frequency at Cesenatico stations. Total abundance (TA) is indicated for each
sampling date
rate values calculated for class "0" during the
July-October and October-February periods
(Table 3).
The estimation of the annual production for
the six stations is shown in Table 4, together with
the estimation of the mean biomass and production/biomass (P/B) ratio. Annual production values ranged from a minimum of 0.12 g_m- 2 _y-l
at the depth of 12 m off Cesenatico to a maximum of 14.78 g e m- 2 _y-l at the depth of 3 m off
Porto Garibaldi. The PIB ratio ranged from 2.18
to 3.62.
Thble 3. Class "0" mean individual growth rate and total density variations of O. fusiformis
during the summer and winter periods, evaluated at the different stations
Stations
Period
Mean individual
Total density variation
growth rate (mg month-I)
(indm- 2 )
4PG (3m)
Jul-Oct
0.48
7140-1396
Oct-Feb
0.34
1396-2079
14 CE (3m)
Jul-Oct
0.17
1492-333
Oct-Feb
0.91
333-75
304 PG (Sm)
Jul-Oct
O.OS
27542-1771
Oct-Feb
O.lS
1771-1479
314 CE (8m)
Jul-0ct
0.04
13717-5429
1004 PG (14m)
Jul-Oct
0.04
7367-3679
Oct-Feb
0.15
3679-1671
1014 CE (12m)
Jul-Oct
0.06
629-221
Oct-Feb
0.04
221-29
267
Station 14 (3m)
775
July 1996
200
TA= 1492
150
100
50
0
Station 304 (8m)
July 1996
TA=13717
150
100
50
....... ,
0
Station 1014 (12m)
July 1996
TA=629
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
f
O~1996
) 100
TA=333
~ l I
~ 50
I I
.~ 0 +-~. ---,---,0,-",. ..... ~. ,-.. •• -..,. . .
.,.., ....... ~ ... -,.. ~, ~. -r--,. ,
Oct 1996
TA= 5429
,.,-,
Oct 1996
TA=221
150 1
100
I
50
•
I.
o~,--,-~, ~.~.~,~,~~--,-r-r~,-,~,~
-g 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.1 0.3 0.5 0.1 0.9 1.1 1.3 1.5 1.7 1.9
::.
II)
Feb 1997
Feb 1997
u
~=n
~=N
j ~ 1 ,
.~-. , ,-,-,-, ~~ +l-,-r-r--r-o~~-,-.,-,.-.-..-r--,-,.--,--,
§
01 03 05 07 09 11 13 15 11 19
0103 05 07 09 1113 15 17
~
May 1997
~+l~,~r-r~~~~,-.~~~,!~~--=~. ~58~
5~1, ,_
-,.,.
July 1997
TA=54
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
1000 1
May 1997
50: +_ ~,......~~, ••• ,..I,JIII,I.I-; • .,..\11 ...... , T.~A~~_~4.,..,B'"r~....,
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
5~ 1 , , . , , , , . , .. ,
July 1997
TA=25
0.1 0.3 0.5 0.7 0..9 1.1 1.3 1.5 1.7 1.9
Width of first abdominal segment (mm)
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
~ 1 . ,.,Feb 1997
TA=29
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
Fig. 4. Seasonal distribution of O. fusiformis size frequency at Cesenatico stations. Total abundance (TA) is indicated for each
sampling date
rate values calculated for class "0" during the
July-October and October-February periods
(Table 3).
The estimation of the annual production for
the six stations is shown in Table 4, together with
the estimation of the mean biomass and production/biomass (P/B) ratio. Annual production values ranged from a minimum of 0.12 g_m- 2 _y-l
at the depth of 12 m off Cesenatico to a maximum of 14.78 g e m- 2 _y-l at the depth of 3 m off
Porto Garibaldi. The PIB ratio ranged from 2.18
to 3.62.
Thble 3. Class "0" mean individual growth rate and total density variations of O. fusiformis
during the summer and winter periods, evaluated at the different stations
Stations
Period
Mean individual
Total density variation
growth rate (mg month-I)
(indm- 2 )
4PG (3m)
Jul-Oct
0.48
7140-1396
Oct-Feb
0.34
1396-2079
14 CE (3m)
Jul-Oct
0.17
1492-333
Oct-Feb
0.91
333-75
304 PG (Sm)
Jul-Oct
O.OS
27542-1771
Oct-Feb
O.lS
1771-1479
314 CE (8m)
Jul-0ct
0.04
13717-5429
1004 PG (14m)
Jul-Oct
0.04
7367-3679
Oct-Feb
0.15
3679-1671
1014 CE (12m)
Jul-Oct
0.06
629-221
Oct-Feb
0.04
221-29