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Turbot - Baltic Sea, 2012
Marine Resource  Fact Sheet
ICES Advice 2012
Turbot - Baltic Sea, 2012
Fact Sheet Citation  
Turbot in Subdivisions 22 - 32 (Baltic Sea)
Owned byInternational Council for the Exploration of the Sea (ICES) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Turbot, fr - Turbot, es - Rodaballo, zh - 大菱鲆, ru - Калкан
Geographic extent of Turbot - Baltic Sea
Main Descriptors
Considered a single stock: No        Spatial Scale: Sub-Regional
Management unit: Yes
 
 
Habitat and Biology
Depth zone: Shelf (50 m - 200 m).   Vertical distribution: Demersal/Benthic.  


In the Baltic Sea turbot (Psetta maxima) occurs in the western and southern area up to the Sea of Åland. Turbot mainly feeds on sandeel, herring, and gobies. Turbot spawn in shallow waters and the metamorphosing post-larvae migrate close to shore into shallow water for feeding. Female growth and size-at-age are significantly higher than for males. This leads to higher exploitation of females.
Geographical Distribution
Jurisdictional distribution: Shared between nations

Water Area Overview
Spatial Scale: Sub-Regional


Baltic Sea
Geo References
Resource Structure
Considered a single stock: No
Exploitation
 

The fisheries


Turbot are caught as a bycatch in trawling and gillnetting and in some years as a target species in a gillnet fishery.
Catch distribution No information on total catch (2011), 301 t landings (recently mainly from trawl fishery).
Assessment
 
Scientific Advice

Based on the ICES approach for data-limited stocks, ICES advises that catches should be less than 220 tonnes.

This is the first year that ICES is providing quantitative advice for data-limited stocks (see Quality considerations).
Overall Assessment Results
Figure 8.4.12.1 Turbot in Subdivisions 22–32 (Baltic Sea). ICES estimates of landings (in tonnes, left panel). Combined 1st and 4th quarters cpue (no./hr) (weighted average per depth stratum area), of fish equal to or larger than 20 cm, from the Baltic International Trawl Survey (BITS-Q1+Q4) in Subdivisions (SD) 22–28 (data from ICES DATRAS database, right panel).
Assessment Model

Quality consideration


Almost all aspects of data collection need to be improved to get a better understanding of the state of turbot in the Baltic.

The advice is based on a combined abundance index from two surveys, used as an indicator of stock size. The uncertainty associated with the index values is not available.

The methods applied to derive quantitative advice for data-limited stocks are expected to evolve as they are further developed and validated. The harvest control rules are expected to stabilize stock size, but they may not be suitable if the stock size is low and/or overfished.

Scientific basis

Assessment type Survey trends.
Input data Commercial landings and survey data from the Baltic International Trawl Survey (BITS-Q1+Q4).
Discards and bycatch Information not available.
Indicators None.
Other information None.
Working group report WGBFAS
Management
Management unit: Yes


Management plans


No specific management objectives are known to ICES.
Biological State and Trend
Exploitation rate: Unknown
Abundance level: Unknown
Figure 8.4.12.1

The average stock size indicator (number/hour) in the last two years (2010–2011) are 17% lower than the abundance indices in the three previous years (2007–2009). There are indications that turbot should be treated as several local stocks, but there are not enough data to identify these stocks.
Source of information
 

The above excerpts are from the first two pages of the ICES advice, the supporting information to this advice can be read in full at the following reference:
ICES. Turbot in Subdivisions 22–32 (Baltic Sea). Report of the ICES Advisory Committee, 2012. ICES Advice, June 2012. Click to openhttp://www.ices.dk/committe/acom/comwork/report/2012/2012/tur-2232.pdf
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