|
| Marine Resource Fact Sheet |
| |
| European hake - Northern Spain, 2008 |
 | Merluccius merluccius - Northern Spain |
| | Owned by | General Fisheries Commission for the Mediterranean (GFCM)
more>> |
|
|
| Main Descriptors | Considered a single stock: Yes
Spatial Scale: Sub-Regional
|
| Considered a single stock: A group of individuals in a species occupying a well defined spatial range independent of other stocks of the same species. It can be affected by random dispersal movements and directed migrations due to seasonal or reproductive activity. |
| Spatial Scale: Spatial scale contains a standard term such as Global, Regional (e.g. for the whole Atlantic), sub-regional (e.g. for a part of the Atlantic), national, local (for sub-national levels). |
| 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. |
| | | | | | Habitat and Biology Climatic zone: Temperate. Depth zone: Shelf 50 200m; Slope 200 1000m. Horizontal distribution: Neritic. Vertical distribution: Demersal/Benthic. Geographical Distribution Jurisdictional distribution: Straddling between High Seas and EEZ Water Area Overview Spatial Scale: Sub-Regional Northern Spain (Northern part) from Cape Creus the Delta of Ebre RiverGeo References  | | Distribution of European hake - Northern Spain
| GFCM geographical sub-areas | 6: Northern Spain |
| | | | | | Other georeferences
| FAO Fishing Statistical Division Areas | 37.1.1: Balearic |
| | | | | | Intersecting Major FAO areas and LME areas |
The following area codes have been found as intersecting the distribution of European hake - Northern Spain Resource Structure Considered a single stock: Yes Exploitation Fishing is carried out five days a week.
Hake is exploited by bottom trawl, gillnet and longline, each fishing gear targeting a given length range. Highest landings, both in weight and in numbers, correspond to bottom trawling.
Recruits are the main component of the overall landings. The catch mean age is around 1 year.
Annual hake landings along the Catalan Coast since late nineties were around 2000 tonnes and were produced by a total effort of between 55000-65000 fishing days (number of days with hake landing, all fishing gears combined).
Landings in 2008 were highest for the period 2000-2008, and correspond to the increase in bottom trawl landings; landings by the artisanal vessels and longliners in 2008 decreased regarding the previous year. In 2007 hake annual landings were the lowest for the period 1988- 2008. Information on Operational Units exploiting this resource will be soon available at the following link: GSA 06 European Hake (Merluccius merluccius)Assessment Data Input data for the analysis is the 2008 pseudocohort (annual size distribution of bottom trawl, gillnet and longline). Results are presented for VPA, Y/R and a transition analysis considering a reduction of bottom trawl effort by 20%. Assessment Model Virtual population analysis (VPA), Yield per recruit analysis (Y/R) The program VIT (Lleonart and Salat, 1992) is designed for the analysis of marine populations, exploited by one or several gears, based on single species' catch data (structured by age or size). The main assumption underlying the model is that of steady state, because the program works with pseudo-cohorts and it is therefore not suitable for historical data series. The program uses the catch data and ancillary parameters for rebuilding the population of the species and the mortality vectors affecting it by means of Virtual Population Analysis (VPA). Once the virtual population has been rebuilt, an analysis of the fishery can be carried out with the aid of several tools: Comprehensive VPA results, Yield-per-Recruit analysis based on the fishing mortality vector, analysis of sensitivity to parameter values and transition analysis. The latter permits non-equilibrium analysis of how a shift in exploitation regime is reflected in the fisheries. All these tools can be applied to specific studies of competition among fishing gears. Transition analysis Results The effect on Y/R of a reduction of 20% of bottom trawl effort would result in a decrease of Y/R of trawl the year first year after the reduction, and already in the next year Y/R would recover the previous values and in the third year Y/R higher than before the reduction might be expected. This reduction could be implemented by reducing the time of fishing, that is, fishing four days a week (instead of the current 5 days a week).
Since gillnet and longline exploit higher sizes, the effect of trawl effort reduction would be expected by year 2 after the implementation of the measure. The increase in biomass (biomass per recruit and spawning stock biomass per recruit) is evident from the first year after the reduction of trawl effort. Scientific Advice For management considerationsFishing effort of bottom trawl should be reduced. The bulk of the catch of this gear consists of recruits (mean age of the catch around 1 year).
Results of the implementation of a reduction by 20% of trawl fishing effort shows that in the first year bottom trawl yield per recruit would decrease, and from then, Y/R would increase already in the second year, with no losses in the first year. The benefit of this measure is more evident in the increase in biomass, observed already in the first year after the reduction in trawl effort. The reduction in trawl effort by 20% could be implemented by reducing the number of fishing days during the week, from the current five days, to four. Biological State and Trend Exploitation state: OverexploitedExploitation rate: High fishing mortality
Abundance level: Low abundance The exploitation is based on recruits. This stock is overexploited (growth and danger of recruitment overexploitation). Nevertheless, the landings in 2008 were much higher than those in the previous year, suggesting a refugium for the spawning stock. Source of information “Assessment of hake (Merluccius merluccius) in the GSA 06 (nothern part). In: Report of the 11th session of the Sub-Commitee on Stock Assessment (SCSA)” . Martín P., Recasens L., Lleonart J. FAO-GFCM Malaga, Spain, 30 November - 3 December 2009 2009 FAO  . |
|
| |
|
Map legend