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LANDING TIME-SERIES DATA IN A COASTAL MEDITERRANEAN LAGOON SYSTEM. ECOLOGICAL STAGE, TEMPORAL PATTERNS AND FISHERIES PRODUCTION FORECASTING ANALYSIS Zoulias Th. HCMR, Institute of Oceanography, P.O. Box 19013, Anavissos, Attica, e-mail: tzoulias@ath.hcmr.gr. THE STUDY AREA. Logarou lagoon: - PowerPoint PPT Presentation
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LANDING TIME-SERIES DATA IN A LANDING TIME-SERIES DATA IN A COASTAL MEDITERRANEAN LAGOON COASTAL MEDITERRANEAN LAGOON
SYSTEM. ECOLOGICAL STAGE, SYSTEM. ECOLOGICAL STAGE, TEMPORAL PATTERNS AND FISHERIES TEMPORAL PATTERNS AND FISHERIES
PRODUCTION FORECASTING PRODUCTION FORECASTING ANALYSISANALYSIS
Zoulias Th. Zoulias Th.
HCMR, Institute of Oceanography, P.O. Box 19013, HCMR, Institute of Oceanography, P.O. Box 19013, Anavissos, Attica, e-mail: tzoulias@ath.hcmr.grAnavissos, Attica, e-mail: tzoulias@ath.hcmr.gr
THE STUDY AREATHE STUDY AREA
Logarou lagoon:
Total surface = 26km2
Mean production = 134tn
Depth = 0,2m – 1,6m
Reed beds domination
Sand muddy bottom
AIMS OF THE STUDYAIMS OF THE STUDY to analyze the modifications of the ecosystem to analyze the modifications of the ecosystem
structure in the Logarou lagoon by comparing the structure in the Logarou lagoon by comparing the time series of landings and the ecological indicestime series of landings and the ecological indices
to evaluate temporal variations in the study to evaluate temporal variations in the study lagoon based on the fish biomass distribution lagoon based on the fish biomass distribution across trophic levels and across trophic levels and
to estimate a short-term environmental and to estimate a short-term environmental and fisheries state in the study systemfisheries state in the study system
A coastal lagoon as, due to its finite magnitude, it is possible to accurately assess the extension of the fishing ground and to obtain more reliable fisheries data. So, the differentiation of fishing effects from long-term changes associated with other anthropogenic and natural disturbances can be allowed.
The IDEA:The IDEA:
• EcologicalEcological indices: indices:
Material & Methods
•BTLS as indicator of multifactor impacts
•ARIMA forecasting model
• Annual fishery landings data from the barrier Annual fishery landings data from the barrier fish traps for the period = 1980 – 2003fish traps for the period = 1980 – 2003
FiB=log(Yk/Yo)+(mTrLK-mTrLo)*log(1/TE)FiB=log(Yk/Yo)+(mTrLK-mTrLo)*log(1/TE)Yk=Landings in year k, Yo=Landings for the first year Yk=Landings in year k, Yo=Landings for the first year (1980)(1980)(TE=Trophic energy estimated as 10%)(TE=Trophic energy estimated as 10%)P/DP/D=Ratio between the plankton feeder groups =Ratio between the plankton feeder groups and the predators-benthic groupsand the predators-benthic groups
mTrL=mTrL=Σ(ΥΣ(Υjk*TLj)/jk*TLj)/ΣΥΣΥjkjkYjk=the landing of species j in the year kYjk=the landing of species j in the year kTLj=1+TLj=1+ΣΣDCij*TLi (number ranging from 2-5)DCij*TLi (number ranging from 2-5)
FiB=0, TL changes and changes in catch are matched
FiB<0, Discarding occurs or fisheries overexploitation
FiB>0, Increase in primary production or Expanded ecosystem
P/D value alterations = alterations in nutrient enrichment or fisheries management
Coupling fisheries production and ecological indices
Group Scientific name Common name Estimated TL Fish predators Dicentrarchus labrax seabass 3,47
Anguilla anguilla european eel 3,85 Sparus aurata seabream 3,42
Fish detrivorus Mugilidae sp., mullets 2,14 Fish plankton feeders Atherina boyeri Sand smelt 3,3
Belone belone garpike 4,21 Fish benthic Solea solea sole 3,28
Gobius sp., goby 3,24 Shrimps Palaemon sp., prawn 2,85
The landings data is composed by 9 species or group of fishes that were aggregated into 5 trophic groups
RESULTS: COMPOSITION OF THE RESULTS: COMPOSITION OF THE SPECIESSPECIES
PressuresPressures, , StatesStates and and ImpactsImpacts
Carrying capacity
Geomorphological character of the lagoon
Dams constructions
Agriculture Animal husbandry Drainage activities Non-diffused sources
Fisheries management
Constructions in the lagoon
Aquifers & river quality
Environmental status of the lagoon
Amvrakikos gulf status Recruitment
Fishfauna trophic mesh alterations
Phytobenthos Zoobenthos alterations
Fry enrichment
Overexploitation
Sea aquaculture
Physicichemical alterations
RESULTS: Fisheries landingsRESULTS: Fisheries landings
0
20000
40000
60000
80000
100000
120000
Mugilidae sp., S. aurata D. labraxS. solea Gobius sp., A. anguillaPalaemon sp., A. boyeri B. belone
'81
'85
'89
'93 '97'99
'01
a
LANDINGS (ln)
11
11,2
11,4
11,6
11,8
12
12,2
12,4
Fishing gears & leasing regime stableFDFW effect in the period 1994-1997
2,3
2,4
2,5
2,6
2,7
2,8
2,9
3
3,1
2,8 2,9 3 3,1 3,2 3,3 3,4 3,5
log CPUE
mT
rL
1981
1982
1983
1980
19841987
1986
1989
1988
1990
1991
1992
1993
1994
1995
1998
1997
1999
20002003
2001
2002
1985
1996
RESULTS: ECOLOGICAL INDICESRESULTS: ECOLOGICAL INDICES
2,2
2,4
2,6
2,8
3
3,2
3,4
3,6mTrL
93
88
90
97
00
-1,2
-1
-0,8
-0,6
-0,4
-0,2
0
0,2
0,4
0,6
0,8
1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
FiB
00
97
93
90
88
c
0
1
2
3
4
5
6
7
8
9
1019
80
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
P/D
88
90
93
97
00
RESULTS:RESULTS:
-1,2
-1
-0,8
-0,6
-0,4
-0,2
0
0,2
0,4
0,6
0,8
1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
FiB
00
97
93
90
88
c
0
1
2
3
4
5
6
7
8
9
10
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
P/D
88
90
93
97
00
2,2
2,4
2,6
2,8
3
3,2
3,4
3,6
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
mTrL
93
88
90
97
00
LANDINGS (ln)
11
11,2
11,4
11,6
11,8
12
12,2
12,4
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
Ecological indices showed alterations in the system structure, decrease in the productivity of the system as well as a positive trend in the system eutrophication. Fisheries landings have a negative trend.
RESULTS: CUMMULATIVE RELATIVE BTLSRESULTS: CUMMULATIVE RELATIVE BTLS
Trend of significant differences between the periods 1980-1984 and 1998-2002 (t-test, p=0,052). Alterations in the fisheries landings as well as in the fisheries composition.
Tendency of change from a sigmoid pattern (blue line), to a linear form (green dashed line).
40
50
60
70
80
90
100
2 2,5 3 3,5 4 4,5
Acc
umul
ated
rel
ativ
e bi
omas
s (%
)
p=0,05
Logarou lagoon
1980-19841998-2002
Forecasts; Model:(0,2,1) Seasonal lag: 12
Input: VAR1
Start of origin: 1 End of origin: 24
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Observed Forecast ± 90.0000%
-10
-5
0
5
10
15
20
-10
-5
0
5
10
15
20
RESULTS: ARIMA forecasting modelRESULTS: ARIMA forecasting model
YEAR MEAN VALUES(kgr/he)
Min(kgr/he)
Max(kgr/he)
2004 4,90 2,63 7,17
2005 5,07 1,12 9,02
2006 5,23 -0,5 11,00
2007 5,40 -2,35 13,15
2008 5,56 -4,33 15,45
•Positive trend of the future main fishing yield
•Limited reliability of the model
YEAR Observed values(kgr/he)
2004 4,21
2005 3,40
2006 ≈0 due to frost
Time-series model=(0,2,1)
Confidence level=90%
Forecasting period=2004-2008
CONCLUSIONSCONCLUSIONS The analysis of the fisheries landings and the The analysis of the fisheries landings and the ecological indices showed a lot of variability that ecological indices showed a lot of variability that hamper consistent and significant identification of hamper consistent and significant identification of trend and dynamics. trend and dynamics.
BTLS index confirmed tracking changes in the BTLS index confirmed tracking changes in the trophic structure. Thorough evaluation is needed to trophic structure. Thorough evaluation is needed to link the shape with specific impacts from the link the shape with specific impacts from the watershed.watershed.
The ARIMA model is introduced by uncertainty The ARIMA model is introduced by uncertainty and an application of another management model is and an application of another management model is needed.needed. Responses in the system must be part of an Responses in the system must be part of an integrated management plan that will cover the integrated management plan that will cover the social-economic activities of the watershed in which social-economic activities of the watershed in which the system belongs.the system belongs.
THANK YOU FOR YOUR THANK YOU FOR YOUR ATTENTION!ATTENTION!
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