GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN (GFCM)SCIENTIFIC ADVISORY COMMITTEE (SAC)Sub-Committee of Stock Assessment (SCSA)

Working Group on Small PelagicsIzmir, Turkey, 22-26 September, 2008

G.S.A. 16, South of Sicily-

Trends in anchovy and sardine populations(1998-2008)

I.A.M.C. C.N.R. – Mazara del Vallo (Italy)

Catch-effort dataCatch-effort data collection was originated in 1997 through a EU-DGXIV funded study coordinated by I.A.M.C.-C.N.R. This study firstly evidenced the socio-economic importance of small pelagic species in the “South of Sicily” sector of the Sicilian Channel (G.S.A. 16 of General Fisheries Commission for the Mediterranean - FAO).

SIC ILIA

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BA T IM E T R IA

I ST I TU T O D I R I C E R C H E SU L L E R I SO R SE M A R I N EE L 'A M B IE N T E

Licata

P. Em pedo cle

Sciacca

M azara del Vallo

Marsala

Pozz allo

Siracusa

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Catch-effort data

Catch-effort census data have been collected at Sciacca port since April 1997.Sciacca is the most important base port for the landing of small pelagic species along the southern Sicilian coast. It was estimated to account for about 2/3 of total small pelagic landings in GSA 16. Two fishing gears are operated: purse seine and pelagic pair trawl.

SIC ILIA

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BA T IM E T R IA

I ST I TU T O D I R I C E R C H E SU L L E R I SO R SE M A R I N EE L 'A M B IE N T E

Licata

P. Em pedo cle

Sciacca

M azara del Vallo

Marsala

Pozz allo

Siracusa

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Catch-effort data

Landings from purse seiners and pelagic pair trawlers are almost exclusively (>90%) composed by sardines (Sardina pilchardus) and anchovies (Engraulis encrasicolus). The main fishing area was located on the southern Sicilian shelf, from Mazara to Licata.

SIC ILIA

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I ST I TU T O D I R I C E R C H E SU L L E R I SO R SE M A R I N EE L 'A M B IE N T E

Licata

P. Em pedo cle

Sciacca

M azara del Vallo

Marsala

Pozz allo

Siracusa

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Sciacca small pelagic fishery

Sciacca small pelagic fishery (purse seiners and pelagic trawlers) is composed by: 15 pairs of pelagic trawlers (Sciacca is the only port along the southern Sicilian coast with this type of fishery); 17 purse seiners from different base ports: 5 Sciacca, 3 Trapani and 9 Terrasini.

N. Nome Unità Matr.

1 Nuovo Risorto 3PE288

1 Nuovo Oriule 3PE523

2 Maria di Fatima 3PE406

2 Umberto Luigi 3PE417

3 Loretta Pulcini 3PE412

3 Calogero Padre C. 3PE625

4San Giuseppe

Secondo 3PE470

4 Valbruna 3PE492

5 Orizzonte Secondo 3PE476

5 Pietro Padre Primo 3PE564

6 Maria Stella del Mare 3PE488

6 Azzurra 3PE592

7 Antonino Padre 3PE612

7 Abramo 3PE648

8 Freccia dell'Est 3PE509

8 Angelita 3PE606

N. Nome Unità Matr.

9 Nuovo Lealdo 3PE604

9 Nuovo S. Pietro 3PE650

10 San Francesco C. 3PE550

10 Nuova Luigia 3PE659

11 Sacro Cuore di Gesù 3PE623

11 Serena 3PE646

12 Santo Padre 3PE622

12 Ardito 3PE630

13 Gaetano Catania 3PE602

13 Portofino 3PE636

14 Immacolata Concezione 3PE593

14 Costantino 3PE599

15 Pietro il Grande 3PE529

15 Città di Viareggio 3PE590

Pairs of pelagic trawlers:

N. Porto Nome Unità Matr. Porto di sbarco

1 Trapani Sansone Primo TP2136 Mazara

2 Trapani Azzurra TP2094 Sciacca

3 Trapani Padre Pio TP2123 Sciacca

4 Terrasini Uragano 3PA625 Mazara

5 Terrasini S. Guglielmo 3PA628 Mazara

6 Terrasini Maria Madre 3PA630 Mazara

7 Terrasini Trilona 3PA536 Mazara

8 Terrasini Nuovo San Silvestro 3PA620 Mazara

9 Terrasini Lorenzo Padre 3PA596 Mazara

10 Terrasini Folgore 3PA632 Mazara

11 Terrasini Santa Rita 7PA1838 Sciacca

12 Viareggio Angelo Padre VG3821 Sciacca

13 Sciacca Padre Peppino 3PE515 Sciacca

14 Sciacca Maristella 3PE552 Sciacca

15 Sciacca Pesce Azzurro 3PE626 Sciacca

16 Sciacca Città di Portoferraio 3PE664 Sciacca

17 Sciacca Rosina 3PE672 Sciacca

Purse seiners:

During the last decade landings (mainly anchovy) have had remarkable interannual fluctuations.

* 2008 data updated to June, 30th.

In the same period total fishing effort maintained quite stable, though pelagic trawl tended to replace purse seine.

Montly effort - P urs e s eine vs P elag ic trawl

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P urs e S eine P elagic trawl

AcousticsAcousticsThe acoustic surveys were carried out in the Strait of Sicily, on The acoustic surveys were carried out in the Strait of Sicily, on the continental shelf off the southern coast of Sicily, during the the continental shelf off the southern coast of Sicily, during the summer (June-July) in 1998, 2000, 2002-2003 and 2005-2008, summer (June-July) in 1998, 2000, 2002-2003 and 2005-2008, and during the autumn (September-October) in 1999, 2000, 2001 and during the autumn (September-October) in 1999, 2000, 2001 and 2004-2005. and 2004-2005.

Biomass evaluations were carried out by applying a standardised Biomass evaluations were carried out by applying a standardised methodology. Applied equipment included:methodology. Applied equipment included:

• SIMRAD EK 500 two-frequency (38, 120 kHz) split beam echo SIMRAD EK 500 two-frequency (38, 120 kHz) split beam echo sounder (EK60 starting from 2005);sounder (EK60 starting from 2005);• pelagic trawl net for experimental hauls with the following pelagic trawl net for experimental hauls with the following characteristics: horizontal opening 13-15 m, vertical opening 6-8 characteristics: horizontal opening 13-15 m, vertical opening 6-8 m, mesh size in the cod-end 10 mm; m, mesh size in the cod-end 10 mm; • acoustic monitoring systems of trawl net positioning (SIMRAD acoustic monitoring systems of trawl net positioning (SIMRAD ITI).ITI).

Calibration procedures were carried out on board using a Calibration procedures were carried out on board using a standard copper sphere.standard copper sphere.

ResultsResults

AnchovyAnchovySardineSardineJULY 2007

12.5° 13° 13.5° 14° 14.5° 15° 15.5°

36.5°

37°

37.5° SicilySciacca

Mazara del Vallo

Porto Empedocle

Licata

Cape Passero

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12.5° 13° 13.5° 14° 14.5° 15° 15.5°

36.5°

37°

37.5° SicilySciacca

Mazara del Vallo

Porto Empedocle

Licata

Cape Passero

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34

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Estimated biomasses (tons) by year and species are shown in the Estimated biomasses (tons) by year and species are shown in the following table:following table:

ResultsResults

During the period 1998-2007, During the period 1998-2007, both sardine and anchovy both sardine and anchovy populations experienced quite populations experienced quite large inter-annual large inter-annual fluctuations. fluctuations.

As regards sardine, biomass As regards sardine, biomass estimates ranged from 6,000 estimates ranged from 6,000 metric tons in July 2002 to metric tons in July 2002 to over 38,000 metric tons in over 38,000 metric tons in July 2005. July 2005.

Anchovy evaluations range Anchovy evaluations range from 6,370 metric tons in June from 6,370 metric tons in June 2006 to about 32,000 metric 2006 to about 32,000 metric tons in October 2005.tons in October 2005.

Echo-surveyEcho-survey SardineSardine AnchovyAnchovy TotalTotal

June 1998June 1998 20,00020,000 7,1007,100 27,10027,100

October 1999October 1999 33,70033,700 20,20020,200 53,90053,900

July 2000July 2000 36,37036,370 11,00011,000 47,37047,370

September 2000September 2000 24,80024,800 11,05011,050 35,85035,850

October 2001October 2001 10,05410,054 22,95022,950 33,00433,004

July 2002July 2002 6,0006,000 11,50011,500 17,50017,500

June 2003June 2003 9,5009,500 9,2009,200 18,71018,710

October 2004October 2004 17,96017,960 9,8209,820 27,78027,780

July 2005 July 2005 21,21921,219 20,72020,720 41,92141,921

October 2005October 2005 38,79538,795 32,13832,138 70,93370,933

June 2006June 2006 10,22010,220 6,3706,370 16,59016,590

June 2007June 2007 11,04311,043 6,7256,725 17,76817,768

Sardine population experienced a decreasing trend up to 2002, from Sardine population experienced a decreasing trend up to 2002, from 36,000 t in 2000 to just 6,000 t in 2002, with a recovering in the 36,000 t in 2000 to just 6,000 t in 2002, with a recovering in the following years up to 2005. Anchovy and sardine exhibit a similar following years up to 2005. Anchovy and sardine exhibit a similar fluctuation pattern during the last years, including the “collapse” in fluctuation pattern during the last years, including the “collapse” in 2006, confirmed by the 2007 estimates. 2006, confirmed by the 2007 estimates.

DiscussionDiscussion

Acoustic biomass estimates (metric tons)

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June 1998 October1999

July 2000 September2000

October2001

July 2002 June 2003 October2004

July 2005 October2005

June 2006 June 2007

Sardine Anchovy Total

DiscussionDiscussionComparisons between landings and biomass show that acoustic Comparisons between landings and biomass show that acoustic estimates are largely consistent with catch levels recorded in estimates are largely consistent with catch levels recorded in Sciacca port during the year following the evaluation campaigns. Sciacca port during the year following the evaluation campaigns.

Combining acoustic biomass evaluations and reported landings we Combining acoustic biomass evaluations and reported landings we obtained the following exploitation rates estimates.obtained the following exploitation rates estimates.

DiscussionDiscussion

Exploitation rate (Anchovy)

0.05.0

10.015.020.025.030.035.040.045.050.0

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

%

landings(t+1)/biomass(t)

Exploitation rate (Sardine)

0.05.0

10.015.020.025.030.035.040.045.050.0

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

%

landings(t+1)/biomass(t)

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