Striped red mullet - Balearic Islands, 2010
Marine Resource  Fact Sheet
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Stock status report 2011
Striped red mullet - Balearic Islands, 2010
Fact Sheet Citation  
Mullus surmuletus - Balearic Islands
Owned byGeneral Fisheries Commission for the Mediterranean (GFCM) More
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Species:
FAO Names :  en - Surmullet, fr - Rouget de roche, es - Salmonete de roca
Geographic extent of Striped red mullet - Balearic Islands
Area Details Advanced search
Main Descriptors
Considered a single stock:  Biological Stock        Spatial Scale: Sub-Regional
 
 
Habitat and Biology
Climatic zone: Temperate.   Bottom type: Hard bottom.   Depth zone: Shelf 50 200m.   Horizontal distribution: Neritic; Littoral.   Vertical distribution: Demersal/Benthic.  

Geographical Distribution
Jurisdictional distribution: Straddling between High Seas and EEZ

Water Area Overview
Spatial Scale: Sub-Regional


Balearic Islands
Geo References
Resource Structure
Considered a single stock:  Aq Res Struct
Exploitation
 

Striped red mullet (Mullus surmuletus) is one of the most important target species in the trawl fishery developed by around 37 vessels off Mallorca (Balearic Islands, GSA05). A fraction of the small-scale fleet (~50 boats) also directs to this species during the second semester of the year, using both trammel nets and gillnets. During the last decade, the annual landings of this species have oscillated between 74-117 and 16-29 t in the trawl and small-scale fishery, respectively. In the GSA05, commercial trawlers employ up to four different fishing tactics (Palmer et al. 2009), which are associated with the shallow and deep continental shelf, and the upper and middle continental slope (Guijarro and Massutí 2006; Ordines et al. 2006). Vessels mainly target striped mullet (Mullus sumuletus) and European hake (Merluccius merluccius) on the shallow and deep shelf respectively. However, these two target species are caught along with a large variety of fish and cephalopod species. The Norway lobster (Nephrops norvegicus) and the red shrimp (Aristeus antennatus) are the main target species on the upper and middle slope respectively. The Norway lobster is caught at the same time as a large number of other fish and crustacean species, but the red shrimp fishery is the only Mediterranean fishery that could be considered monospecific.


Assessment
 
Data

The stock of Mullus surmuletus of the GSA05 has been assessed using data from both the trawl and the small-scale fishery on a time series covering ten years (2000-2010). Monthly size composition of catches, official landings and the biological parameters estimated within the framework of the Data Collection Programme (2003-2004) were used. CPUE from commercial trawl fleet (2000-2010) and bottom trawl surveys (2001–2010) were also used. The vector of natural mortality by age was calculated from Caddy´s (1991) formula, using the PROBIOM Excel spreadsheet (Abella et al., 1997).
Assessment Model
Type:  Age-structured
Extended survivors analysis (XSA)
Methodology

The assessment has been carried out applying tuned Virtual Population Analysis on the cohorts present during 2000-2010 and on a mean pseudo-cohort from that period. The XSA were run using the Lowestoft VPA program (Darby and Flatman, 1994).
Results

Population

The Spawning Stock Biomass and Recruitment estimates for 2010 resulted as 165 t and 546 t, respectively.



Fishing mortality rates

F mortalities resulted as: F1-4 = 1.11, F1-5 = 0.96
Assessment Model
Type:  Others
Yield per Recruit (Y/R)
Methodology

The Y/R was done in an Excel spreadsheet.
Results

2000-2010: Fcurrent = 0.55, Fmax = 1.10, F0.1 = 0.26, Y/R = 15.71 g.
Scientific Advice

For management consideration

Reduce F by reducing the effort and improving the selection pattern of the fishery.
Biological State and Trend
 Exploitation state: OverexploitedExploitation rate: Moderate fishing mortality
Abundance level: Intermediate abundance

Although stock abundance and biomass did not show any significant trend, both recruitment and SSB showed a significant decreasing trend (p<0.05). The stock is in overfishing status.
Source of information
 
Report of the Working Group on Stock Assessment of Demersal Species. FAO-GFCM Chania, Crete (Greece) 24-29 October 2011. 2011 FAO Click to open.
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