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!