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| Fact Sheet Title Fact Sheet |
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| Red mullet - Gulf of Lion |
 | Mullus barbatus - Gulf of Lion (GSA 7) |
| | Data Ownership | | This document provided, maintained and owned by General Fisheries Commission for the Mediterranean (GFCM) , is part of GFCM Stock Status Reports data collection. |
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| ident Block | ident Block | | | | Species List: | | Species Ref: en - Red mullet, fr - Rouget de vase, es - Salmonete de fango, ru - Султанка обыкновенная (=барабулька) |
Fishery IndicatorsProduction: Catch |
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| ident Block Red mullet - Gulf of Lion
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| gfcm Sub Area |
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| 7 | Gulf of Lion |
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| Aq Res | Biological Stock: No
Value: Sub-Regional
Management unit: Yes
Reference year: 2019
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| Considered a management unit: An aquatic resource or fishery is
declared as [Fishery] Management Unit if it is
effectively the focus for the application of selected
management methods and measures, within the broader
framework of a management system. According to the FAO
Glossary for Responsible Fishing, "a Fishery Management
Unit (FMU) is a fishery or a portion of a fishery
identified in a Fishery Management Plan (FMP) relevant
to the FMP's management objectives." FMU's may be
organised around fisheries biological, geographic,
economic, technical, social or ecological dimensions ,
and the makeup and attribute of a fishery management
unit depends mainly on the FMP's management
objectives. |
| Jurisdictional distribution: Jurisdictional qualifier (e.g.
"shared", "shared - highly migratory") of the aquatic
resource related with its spatial distribution. |
| Environmental group: Classification of the aquatic
resource according to the environmental group (e.g.
pelagic invertebrate, or demersal fish) to which the
species belong. |
| Reference Year: The Reference Year is the last year considered in the stock assessment and/or fishery status. |
| | | | | | Aq Res State Trend 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: 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  | | Water Area Overview Red mullet - Gulf of Lion
| gfcm Sub Area | 7: Gulf of Lion |
| | | | | | Water Area Overview
| fao Div | 37.1.2: Gulf of Lion |
| | | | | | Water Area Overview |
Water Area OverviewRed mullet - Gulf of Lion Aq Res Struct Biological Stock: No 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 Red mullet ( Mullus barbatus) in the Gulf of Lion (GSA 7) is a shared stock exploited by both Spanish and French trawlers, and since 2011 also by French artisanal gear (gillnets and trammel nets). The French fleet is usually responsible for ~90 percent of the catch, most of which results from trawlers (> 95 percent). Trawlers exploit smaller size classes than nets (T: (7-25 cm) G: (12-30 cm)). Landings in recent years vary around 300 tonnes with a maximum in 2016 and the minimum in 2002. Landings of gear other than otter trawls, gillnets and trammel nets are on average less than 1 percent. Since 2014, the French trawl fleet are separated by otter trawls, midwater otter trawls and otter twin trawls. The majority of landings are due to otter trawls, but otter twin trawls have an increasing importance in the last years. Discards were regularly reported since 2010. They are mostly composed of small individuals and account for 1-5 percent of the landed biomass, depending on year. In 2019, discards of small individuals have been particularly important. No analysis on effort data were carried out during the meeting. Fishery Indicators | Type | Measure | Value | Unit | Time period |
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| Production | Catch | 320 | tonnes | 2019 | | Catch | 342 | tonnes | 2018 | | Catch | 301 | tonnes | 2017 | | Catch | 418 | tonnes | 2016 | | Catch | 386 | tonnes | 2015 | | Catch | 359 | tonnes | 2014 | | Catch | 308 | tonnes | 2013 | | Catch | 218 | tonnes | 2012 | | Catch | 274 | tonnes | 2011 | | Catch | 267 | tonnes | 2010 | | Catch | 149 | tonnes | 2009 | | Catch | 131 | tonnes | 2008 | | Catch | 208 | tonnes | 2007 | | Catch | 215 | tonnes | 2006 | | Catch | 176 | tonnes | 2005 | | Catch | 177 | tonnes | 2004 | | Catch | 176 | tonnes | 2003 | | Catch | 123 | tonnes | 2002 |
Bio Assess Data The use of fast growth parameters was questioned and these were compared with two alternatives: i) fitting a Von Bertalanffy model to the age-reading data available for GSA 7; and ii) building a global age-length-key (ALK) directly from the data. Cohort consistency is clearly improved when age slicing is performed with either the fitted growth model or the ALK. Between both, ALK provides a slightly better cohort consistency. Therefore the choice was for ALK to perform the assessment. For the purpose of computing biomass and average weights at age from numbers at length, a length-weight relationship fitted on individual DCF sample data - the same that were used to produce the ALK was used. It was assumed that young individuals reach maturity when they arrive to age 1 on 1 July. For ages superior to one all individuals are therefore considered as adults. Natural mortality was based on the Chen and Watanabe formula. French and Spanish DCF data were provided from 2002 to 2019. The input data for the assessment were the landings and discards at age MEDITS data at age, average weight-at-age of landings, discards and survey. Assess Models Type: Age-structured a4a SCAA (a4a) (Jardim et al. 2015) and FLBRP package FLR. The assessment was carried out over the period 2002-2019, calibrated with fishery-independent survey abundance index (MEDITS). To select the final model for assessment, combinations of various options for the three submodels regarding fishing mortality, survey catchability and stock-recruitment inspired from a previous assessment and other areas (notably GSAs 5 and 6) were investigated. All combinations of options for the three submodels were tested, recovering Bayesian information criterion and generalised cross validation score for each combination. 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.  https://www.fao.org/3/cb7622en/cb7622en.pdfReport of the Working Group on Stock Assessment of Demersal Species (WGSAD). Online, 18–23 January 2021.  https://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. https://www.fao.org/3/cb2427en/cb2427en.pdfFAO. 2016. The State of Mediterranean and Black Sea Fisheries. General Fisheries Commission for the Mediterranean. Rome, Italy. https://www.fao.org/3/i5496e/i5496e.pdfFAO 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. https://www.fao.org/3/i4381b/i4381b.pdf |
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