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Red mullet - Ligurian and North Tyrrhenian Sea
Fact Sheet Title  Fact Sheet
Stock status report 2021
Red mullet - Ligurian and North Tyrrhenian Sea
Fact Sheet Citation  
Mullus barbatus - Ligurian and North Tyrrhenian Sea (GSA 9)
Owned byGeneral Fisheries Commission for the Mediterranean (GFCM) – ownership
ident Blockident Blockdisplay tree map
 
Species List:
Species Ref: en - Red mullet, fr - Rouget de vase, es - Salmonete de fango, ru - Султанка обыкновенная (=барабулька)

Fishery Indicators
Production: Landed Volume
ident Block Red mullet - Ligurian and North Tyrrhenian Sea
Aq Res
Biological Stock: Yes         Value: Sub-Regional
Management unit: Yes        Reference year: 2019
 
 
Aq Res State Trend
Aq Res State Trend
Aq Res State Trend Aq Res State Trend
Aq Res State TrendIn overexploitation (F/Fref = 1.67)Not applicable
Aq Res State TrendRelatively high biomassNot applicable
Aq Res State Trend
Aq Res State TrendNot applicable

In overexploitation, with relatively high biomass.
[The GFCM methodology to provide stock status and management advice is described in the Appendix F of the Sixteenth Session of the Scientific Advisory Committee Report. See the Bibliography section.]
Habitat Bio
Climatic Zone: Temperate.   Bottom Type: Soft bottom.   Depth Zone: Coastal (0 m - 50 m); Shelf (50 m - 200 m).   Horizontal Dist: Neritic; Littoral.   Vertical Dist: Demersal/Benthic.  

Geo Dist
Geo Dist: Shared between nations

Water Area Overview
Spatial Scale: Sub-Regional

Water Area Overview
Aq Res Struct
Biological Stock: Yes


Stock assessment in the GFCM area of application is often conducted by management units, based on GSAs. This method does not ensure that the whole stock is assessed, since stocks may cover several different management units. In some cases, when there is scientific evidence of a stock spreading through different GSAs, as well as information on species from different GSAs, existing information is combined across GSAs. This is then defined as a “joint stock assessment of a shared stock”. The GFCM recommends that when scientific evidence of shared stocks exists, joint stock assessments should be attempted. A number of activities aimed at achieving a better definition of stock boundaries are currently being conducted at the GFCM level. [The State of Mediterranean and Black Sea Fisheries, 2016]
Exploit
 

The fishing gear used to catch red mullet in GSA 9 together with other species (mixed catches) are gillnets, trammel nets and otter trawls. Discards of red mullet in GSA 9 occur mainly from the catches of otter trawls. Discard data were available in 2006, and for all years since 2009. For the assessment purposes, in the years where discard data were missing, approximations were made taking into account the percentage of catch discarded in the previous and/or following year.
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionLanded Volume 844.0tonnes2019
Landed Volume 1204.8tonnes2018
Landed Volume 1460.7tonnes2017
Landed Volume 1221.6tonnes2016
Landed Volume 1183.4tonnes2015
Landed Volume 1181.4tonnes2014
Landed Volume 693.3tonnes2013
Landed Volume 692.9tonnes2012
Landed Volume 805.5tonnes2011
Landed Volume 747.9tonnes2010
Landed Volume 728.3tonnes2009
Landed Volume 727.1tonnes2008
Landed Volume 1096.0tonnes2007
Landed Volume 1049.6tonnes2006
Landed Volume 708.5tonnes2005
Landed Volume 580.7tonnes2004
Landed Volume 1056.7tonnes2003
Bio Assess
 
Data

Growth parameters of red mullet in GSA 9 were available from 2006 to 2019 from DCF data. For the aim of the stock assessment a set of von Bertalanffy parameters given by the average along the years was used. Considering the fact that the assignment of the age in the ALK considered the middle of the year as birth date of red mullet, while the a4a model was parameterized with calendar year, it was agreed to shift growth curve by adding 0.5 to t0 for internal consistency in the stock assessment model. M was estimated according to the Chen and Watanabe model (1989). An agreed vector of maturity was used for all red mullet stocks in the western Mediterranean. DCF was the data source for data on catches, landings, discards, LFDs and MEDITS index over 2004-2019. MEDITS data showed large variations between years. In 2017, the survey was carried out in September-October. Due to the variability of survey timing, age 0 class was not included in the tuning indices used for the assessment. Age slicing using a4aGr of the LFDs of landings, discards and survey has been carried out by sex (in combination with sex ratio at length) model and then data were combined.
Assess Models
Type:  Age-structured
a4a

SCAA model (a4a) (Jardim et al. 2015) and FLBRP package, FLR.
Results

The estimated SSB and recruitment show a sharp increase in recent years giving the highest of the whole time series. This is consistent with the increase in total catch and the increase in the MEDITS abundance survey indices.
Sci Advice

Reduce fishing mortality. STF available.
Management
Management unit: Yes
Sources
 
FAO. 2021. General Fisheries Commission for the Mediterranean. Report of the twenty-second session of the Scientific Advisory Committee on Fisheries, online, 22–25 June 2021. FAO Fisheries and Aquaculture Report No. 1347. Rome.  Click to openhttps://www.fao.org/3/cb7622en/cb7622en.pdf
Report of the Working Group on Stock Assessment of Demersal Species (WGSAD). Online, 18–23 January 2021.  Click to openhttps://www.fao.org/gfcm/technical-meetings/detail/en/c/1412431/
Bibliography
 
FAO. 2020. The State of Mediterranean and Black Sea Fisheries 2020. General Fisheries Commission for the Mediterranean. Rome.  Click to openhttps://www.fao.org/3/cb2427en/cb2427en.pdf
FAO. 2016. The State of Mediterranean and Black Sea Fisheries. General Fisheries Commission for the Mediterranean. Rome, Italy.  Click to openhttps://www.fao.org/3/i5496e/i5496e.pdf
FAO General Fisheries Commission for the Mediterranean/Commission générale des pêches pour la Méditerranée. Report of the sixteenth session of the Scientific Advisory Committee. St. Julian’s, Malta, 17–20 March 2014/Rapport de la seizième session du Comité scientifique consultatif. Saint Julien, Malte, Malte, 17-20 mars 2014. FAO Fisheries and Aquaculture Report/FAO Rapport sur les pêches et l’aquaculture. No. R1102. Rome. 2015. 250 pp.  Click to openhttps://www.fao.org/3/i4381b/i4381b.pdf
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