1) Summary Recommendations
Species |
Area |
Stock Status |
management recommendations |
Merluccius merluccius |
Sub Area 9 |
spawning stock level very low |
fishing effort reduction on multiannual basis (min 15%) |
Sub Area 7 |
- growth overfishing |
- reduction of longline and gillnets effort |
|
SAMED area 1 |
global growth overfishing |
temporary closure of nursery areas |
|
Nephrops norvegicus |
Sub Area 9 |
no over exploitation |
no management advice |
SAMED area 1 |
slight overexploitation to full expoitation |
improve gear to avoid small size fish capture |
|
Aristeus antennatus |
Sub Area 1,5 and 6 |
overexploitation |
effort reduction on the overall stock, irrespective of sex. |
Mullus barbatus |
Sub Area 9 |
full or overexploitation |
spatial and temporal closures |
SAMED area 1 |
full or intense exploitation |
enforce the actual protection of shallow areas |
|
Engraulis encrasicolus |
Sub Area 1. Northern Alboran sea |
biomass increasing |
maintain current effort level |
Sub Area 6, Northern Spain |
biomass increasing |
maintain current effort level |
|
Sub Area 7-6 |
high level of biomass |
maintain current effort level |
|
Sub Area 17 Northern Adriatic |
large biomass fluctuations |
maintain current effort level |
|
Sub Area 22 Aegean Sea |
no comments |
- |
|
Sardina pilchardus |
Sub Area 1. Northern Alboran sea |
unknown |
- |
Sub Area 6 Northern Spain |
biomass fluctuating |
maintain current effort level |
|
Sub Area 3 Southern Alboran Sea |
biomass fluctuating |
- |
|
Sub Area 17 Northern Adriatic |
biomass fluctuating |
market strategies to increase the human consumption |
|
Sub Area 20+22 |
no comments |
- |
1 SAMED area includes GFCM Geographical Sub-Areas 1, 6, 7, 8, 9, 10, 11, 15, 16, 17, 18, 19, 20, 22, and 23)
2) FULL
RECOMMENDATIONS[2]
(For Small Pelagic
and Demersal Species)
SMALL PELAGIC SPECIES:
Stock assessment of Engraulis encrasicolus in Geographical Sub Area 1. Northern Alboran sea
FISHERIES:
Anchovy and Sardine are the main target species of the purse seine fleet in the Northern Alboran Sea. Other accompanying species with lower economical importance are also caught such as: Horse mackerel (Trachurus spp), mackerel (Scomber spp), Atlantic saury (Scomberesox saurus) and gilt sardine (Sardinella aurita).
In the South-Mediterranean Region (from Gibraltar Strait to Cape of Gata) the fleet continuously decreased in the last two decades, from more 230 vessels in 1980 to 120 in 2001. The present fleet has a mean GRT of 17.2.
Only Malaga Bay fishing area, which represents 85% of total landings, has been considered by the WG.
After 1993 minimum a slight recovery of landings was observed in 1996, but a new diminution occurred in the following years, reaching a minimum in 2000. Finally, a strong increment of landings was recorded in 2001, together with an increase of CPUE values, which reached this year the highest level since 1995, despite the autolimitations in the volume of landings decided by the fishermen in order to maintain the market prices.
SOURCE OF MANAGEMENT ADVICE:
Information from fishery: Landings and CPUE trends.
Acoustic survey carried out 2000 to 2001.
STOCK STATUS:
Biomass estimation for Malaga Bay in 2001 survey (13210 tonnes) represented an important increment respect to the previous year situation (1716 tonnes). Since most of the stock is concentrated in Malaga Bay this estimation can be considered as representative of the whole northern Alboran area.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Since that fishing effort was already significantly reduced in number of vessels (from 185 in 1985 to 120 in 2001), and taking into account the good 2001 recruitment, it would be recommendable to maintain the current level of fishing effort. However, taking into account the important fluctuations of this stock and the few age classes composing the catches (practically only 0 and 1), it would be necessary to continue the monitoring of this stock.
SCSA COMMENTS:
The SC endorses the assessment and recommends that, although the image of the stock situation has changed because of the very good last year recruitment, the Subcommittee recommends maintaining the current level of fishing effort
Stock assessment of Sardina pilchardus in Geographical Sub Area 1. Northern Alboran sea
FISHERIES:
Anchovy and Sardine are the main target species of the purse seine fleet in the Northern Alboran Sea. Other accompanying species with lower economical importance are also caught such as: Horse mackerel (Trachurus spp), mackerel (Scomber spp), Atlantic saury (Scomberesox saurus) and gilt sardine (Sardinella aurita).
In the South-Mediterranean Region (from Gibraltar Strait to Cape of Gata) the fleet continuously decreased in the last two decades, from more 230 vessels in 1980 to 120 in 2001. The present fleet has a mean GRT of 17.2.
Only Malaga Bay fishing area, which represents 85% of total landings, has been considered by the WG.
A peak of landings of around 6000 tonnes was found in 1991-1992, but then decreased to an overall mean value of 1000-2000 tonnes during 1994-1998. From 1998 onwards, both landings and CPUE showed an increasing trend, reaching in 2000 and 2001 CPUE values higher than those observed in previous years
SOURCE OF MANAGEMENT ADVICE:
Information from fishery: Landings and CPUE trends
STOCK STATUS:
Unknown
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Taking into account information available it does not seem necessary to recommend any reduction of fishing effort on this stock
SCSA COMMENTS:
No comments
Stock assessment of Engraulis encrasicolus in Geographical Sub Area 6, Northern Spain
FISHERIES:
Anchovy and sardine are the main target species of the purse seine fleet in the Northern Spain. Sardine is the species with the highest amount of catch; on the other hand, anchovy is the most sought due to its economical value.
The present fleet has 191 purse seiners, a 12% smaller than the previous year, with a mean GRT of 32.60.
A peak of landings of around 22000 tonnes was found in 1994, but then decreased to an overall value of 6000 tonnes in year 2000; this value is the lowest for the last fiveteen years.
The anchovy landings represent 80% of the total catch anchovy in Spanish Mediterranean.
SOURCE OF MANAGEMENT ADVICE:
Acoustic surveys carried out from 1990 to 1993, and from 1995 to 2001, between La Nao Cape and Creus Cape (Tramontana Region).
STOCK STATUS:
The period in which the surveys were carried out corresponds to the recruitment season of the species. The most important recruitment area is located between Barcelona and the south of the Ebro River Delta. For this area, the surveys suggested that the recruitment was very low from 1996 to 2000, but the population appeared to have recovered in 2001 to amounts close to the half of those found in 1992, when the highest value was estimated. The estimated biomass for the whole area in 2001 (27000 tonnes) was two times higher than that in 2000.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Taking into account the important fluctuations observed in the recruitment, which have a direct effect on the total biomass of the stock, it is recommended that current levels of fishing effort should be maintained.
SCSA COMMENTS:
The SC endorses the assessment and recommends not to increase the fishing effort
Stock assessment of Sardina pilchardus in Geographical Sub Area 6, Northern Spain
FISHERIES:
Anchovy and sardine are the main target species of the purse seine fleet in the Northern Spain. Sardine is the species with the highest amount of catch; on the other hand, anchovy is the most sought due to its economical value.
The present fleet has 191 purse seiners, a 12% smaller than the previous year, with a mean GRT of 32.60.
Sardina landings have increased from 70´s, reaching a maximun of 53000 tonnes in 1994. For the last years there was a decrease reaching 38000 tonnes in year 2000.
SOURCE OF MANAGEMENT ADVICE:
ECOMED acoustic surveys carried out from 1990 to 1993, and from 1995 to 2001, between La Nao Cape and Creus Cape (Tramontana Region).
STOCK STATUS:
From 1990 to 2001, the estimated biomass fluctuated from 200000 tonnes in 1992 to 50000 tonnes in 2000. The estimation for 2001 was 97000 tonnes, which was double than in the previous year. The most important recruitment corresponded to the years 1991 and 1992, whereas the lower values were found in 2000 and 2001.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Taking into account the present level of biomass and catches, as well as the low level of recruitment detected in the two last years, it would be recommended not to increase the current level of fishing effort.
SCSA COMMENTS:
The SC endorses the assessment and recommendations
Stock assessment of Engraulis encrasicolus in Geographical Sub Area 7-6, Gulf of Lions and North Catalonia
FISHERIES:
Gulf of LIons and North Catalonian anchovy stock is shared by Spanish and French fleets. The Spanish fleet is composed by purse seiners and the French fleet mainly by trawlers and a few purse seine boats.
SOURCE OF MANAGEMENT ADVICE:
Biomass and abundance indices obtained by direct methods from French and Spanish surveys (from 1990 to 1993 and from 1995 to 2001) are analysed and combined, as well as catches and fishing effort series for 1993-2001
STOCK STATUS:
High level of biomass and relatively low catches
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
The WG recommends to maintain the fishing effort and to continue evaluating yearly the state of the stock, due to the close relationship between environment factors and recruitment of the species, that combined with fishing pressure, can result in important fluctuations in the abundance of the stock.
SCSA COMMENTS:
The SC endorses the assessment and recommends not to increase the fishing effort.
Stock assessment of Sardina pilchardus Geographical Sub Area 3 Southern Alboran Sea
FISHERIES:
Sardine is one of the most exploited species in the Moroccan Mediterranean. The landings of this species represent around 80% of the total small pelagics landings. At present the species is exploited by 141 purse seiners, of a mean gross tonnage of 40 tx and mean horsepower 450 cv. The vessels operate all the year, 5-6 days per week,12 to 15 hours at sea per fishing day. During one fishing day two or three fishing operations can be carried out.
Sardine landings have undergone important fluctuations during the period 1984-2000, with a maximum around 28000 toones in 1987, and a minimum value around 9300 tonnes in 1998. The fishing effort (number of fishing days*GRT) has also fluctuated during 1992-2000, with a maximum in 1993 and a minimum in 1998. In 1999 and 2000 the fishing effort increased.
SOURCE OF MANAGEMENT ADVICE:
The method used was LCA, applied to annual length frequency distributions for the period 1990-2000 collected from commercial landings. The sampling port was Al Hoceima, that is the most important fishing port regarding sardine landings in the Moroccan Mediterranean. Data on von Bertalanffy growth parameters are those estimated during Spanish 1998 echo surveys in the Alboran Sea.
STOCK STATUS:
Sardine biomass has decreased during the period 1993-1997 but later, since 1998, a positive trend has been observed.
Results indicate that the optimum fishing mortality F0,1 corresponds to 60% of the current fishing mortality. The stock is thus overexploited. The Fmax could not be estimated because the resulting Y/R curve was asymptotic.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
No management advice nor recommendations were proposed
SCSA COMMENTS:
This is a preliminary assessment of this fishery using this methodology. The SC recommends to continue further analysis with the available data.
Stock assessment of Engraulis encrasicolus in Geographical Sub Area 17 Northern Adriatic
FISHERIES:
Anchovy (Engraulis encrasicolus, L.) is one the most important commercial species of the Adriatic Sea. The small pelagic fishery is particularly diffuse in the Northern and Central Adriatic Sea and sardine is fished by the fleets of Italy, Slovenia, Croatia.
Italian fleet in the Northern and Central Adriatic is composed of about 132 (66 couples) pelagic trawlers (volante) mainly operating from Trieste to Ancona and of about 36 lampara vessels (purse seiners with light) which operates mainly in the Central Adriatic Sea.
Fishing regime (regulations in force in Italy): Since 1988 closing fishing season concerning trawling is also applied to mid-water pair trawlers during Summer (about 45 days of closing season between July and September).
Closing fishing season is not applied for the purse seiners. Fishing activity is suspended during week-end.
Trends in landings: Landed anchovies decreased in the last years (1997-2001).
Discards: Discards are negligible.
SOURCE OF MANAGEMENT ADVICE:
SAC Assessment form VPA tuned with CPUE (Laurec-Shepherd method)
STOCK STATUS:
The estimated stock biomass of Adriatic anchovy by VPA showed a strong fluctuation during the observed period (1975-2001). Collapse occurred in 1987 and the recovery of the stock biomass shows a positive trend. Nevertheless, the biomass level has not reached the previous higher values.
The present amount of catches is about the 17% of estimated biomass.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
The current level of fishing effort should be maintained or slightly increased.
The new research programme supported by FAO-ADRIAMED, entitled "Data Collection and Biological Sampling System on Small Pelagics in the Adriatic Sea (Adriamed-SP)" is now implemented. Data collected with this project should improve the assessment of small pelagics in the Geographical sub area 17, Northern Adriatic.
SCSA COMMENTS:
The SC endorses the assessment and recommends not to increase the effort
The SC noted that in the frame of the ADRIAMED project for the first time an echo-survey has been jointly conducted covering the whole northern Adriatic. The SC recommends to combine this information in the future with on-going assessment programmes in the Adriatic based on VPA
Stock assessment of Sardina pilchardus in Geographical Sub Area 17 Northern Adriatic
FISHERIES:
Sardine (Sardina pilchardus, Walb.) is one of the most important commercial species of the Adriatic Sea. The small pelagic fishery is particularly diffuse in the Northern and Central Adriatic Sea and sardine is fished by the fleets of Italy, Slovenia, Croatia. Italian fleet in the Northern and Central Adriatic is composed of about 132 (66 couples) pelagic trawlers (volante) mainly operating from Trieste to Ancona and of about 36 lampara vessels (purse seiners with light) which operates mainly in the Central Adriatic Sea.
Fishing regime (regulations in force in Italy):
Since 1988 closing fishing season concerning trawling is also applied to mid-water pair trawlers during Summer (about 45 days of closing season between July and September).
Closing fishing season is not applied for the purse seiners. Fishing activity is suspended during week-end.
Trends in landings:
Landed sardines decreased in the last years (1997-2001).
Discards:
No information are available for the last years (2000 and 2001). In the previous period (1987-1999) an average of about 2,000 t/year of discards were estimated by a specific research project.
SOURCE OF MANAGEMENT ADVICE:
SAC Assessment form VPA tuned by commercial CPUE (Laurec-Shepherd method)
STOCK STATUS:
The estimated stock biomass of sardine by VPA showed a peak between 1983 and 1985, then a gradual decrease appeared and the stock reached its lowest value in 1999. In 2000, and in a stronger way in 2001, the sardine estimated biomass increased.
The present level of catches is about the 18% of the estimated biomass.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Monitoring of sardine discards at sea. Market strategies to increase the human consumption of sardine, to diminish discards at sea.
The new research programme supported by FAO-ADRIAMED, entitled "Data Collection and Biological Sampling System on Small Pelagics in the Adriatic Sea (Adriamed-SP)" is now implemented. Data collected with this project will improve assessment of small pelagics in Adriatic.
SCSA COMMENTS:
The SC endorses the assessment and recommends not to increase the effort
Stock assessment of Sardina pilchardus in geographical Sub Area 20+22 Eastern Ionian Sea and Aegean Sea
FISHERIES:
A purse seining fleet based in the ports of Volos, Chalkis, Corinthos and Patras (Greece) operates in the area. No available data on fishing effort, trends in catches, landings and discards.
SOURCE OF MANAGEMENT ADVICE:
The document includes biomass estimation of sardine stocks en central Aegean and eastern Ionian Seas, based on DEPM.
STOCK STATUS:
Total spawning biomass was estimated in 2000 to be 19.826 tonnes
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
No comments
SCSA COMMENTS:
The assessment is considered to be preliminary. The SCSA recommends to organise and conduct a long term programme on biomass estimation and to present a new assessment.
Stock assessment of Engraulis encrasicolus in geographical Sub Area 22 Aegean Sea
FISHERIES:
A purse seining fleet based in the ports of Alexandroupolis, Kavala and Thessloniki (Greece) operates in the area. No available data on fishing effort, trends in catches, landings and discards.
SOURCE OF MANAGEMENT ADVICE:
The DEPM was applied for estimating the anchovy spawning biomass at an area indicated between the Thraki mainland in the north and the isles of Samothraki and Thasos in the south.
STOCK STATUS:
The estimated spawning biomass, in 1999, yielded 13180 tonnes
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
No comments
SCSA COMMENTS:
is the SCSA recommended to the WG to extend the study area and to include the whole spawning ground of the stock in order to increase the precision of the estimation.
The SCSA recommended a standardisation of the methodology used by different groups of the small pelagic WG operating in the same area. Such approach would provide a more accurate evaluation of the stock spawning biomass.
General considerations on small pelagics
In small pelagic fishes, abundance is heavily dependent on recruitment and stock biomass shows high inter-annual variability.
In the fisheries exploiting stocks of anchovies or other small pelagic species, for which the most recent scientific analyses (assessments, DEPM, surveys...) show an evident risk of recruitment overfishing, it is advisable to avoid the catch of fish smaller than their first maturity size.
It would be advisable that biomass estimations be made on a yearly basis in all geographical sub-areas, and scientific advice should be given sufficiently in time to allow the managers to adapt in real time the exploitation to the biological condition of the resources.
DEMERSAL SPECIES:
Stock assessment of Merluccius merluccius Geographical Sub Area 9 Ligurian and northern Thyrrhenian
FISHERIES:
Merluccius merluccius is one of the most important species in the Geographical Sub Area 9, considering both the amount of catch and commercial value. It is fished with different strategies and gears (bottom trawling, gill nets, hooks). Within the area, several fleets operating from the different ports exploit the species. Fishing pattern changes among the ports mainly due to the major use of one or other methods of capture. The fishing pressure in the fishing grounds closer to each port is quite different. About 150 trawlers and a more limited number of vessels belonging to the artisanal fleet exploit the species. Annual landings in the area are around 500 tonnes.
Discard of undersized individuals of the species has been assessed for particular sub-areas and can be considered important. However, in some areas, a reduction of discards and of landings of undersized individuals did recently occur due to enforcement of controls.
SOURCE OF MANAGEMENT ADVICE:
Data sources were trawl-surveys (national and MEDITS programmes) as well as Catch Assessment Surveys that include data collection of size structure of the catches.
Length Cohort Analysis, Composite Production Models and Yield-per-Recruit analysis were used to assess the status of the stocks in the area.
STOCK STATUS:
The species is considered to be fully or overexploited, depending on the fishing grounds where the different fishing fleets operate with different levels of fishing effort. Catch rates and total catches have shown in general negative trends during the last ten years. The current level of the Spawning Stock Biomass if compared with the pristine S.S.Biomass is considered in general too low, suggesting a risk of recruitment overfishing. However, standing stock size estimated through trawl-surveys suggests an increase in biomass of the species in most of the sub-areas of Geographical Sub Area 9. The contradiction between the trends observed from trawl-surveys and commercial data can be explained at least in part by changes in the target in the case of some of the fleets.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
The current level of the spawning stock is very low (not more than 15%) regarding to the pristine level. Therefore a reduction of at least 15% of the fishing effort is considered to be necessary so as to minimise the risk of collapse of the stock. This measure can be complemented with the protection of the geographically stable nursery areas present during the whole year where highly vulnerable juveniles are concentrated.
SCSA COMMENTS:
The SC endorses the assessment and the recommendations
A clear status of overexploitation was detected, therefore a decrease of fishing effort is suggested in order to rebuild the stock, which should be implemented in a multiannual basis.
Stock assessment of Nephrops norvegicus Geographical Sub Area 9 Ligurian and northern Thyrrhenian
FISHERIES:
Nephrops norvegicus is a very important species with a very high commercial value. It is the target of a variable fraction of all the fleets operating in the Geographical Sub Area 9 during the whole year. Annual landings in the area do not reach 100 tonnes.
The species is caugth with the traditional Italian bottom trawl net at depths between 250-500 m.About 40 vessels exploit the species in the area. No discards of the species exist being the size of almost all the individuals caught around or beyond the legal size.
SOURCE OF MANAGEMENT ADVICE:
Data were collected during trawl-surveys (national and MEDITS programmes) as well as from Catch Assessment Surveys that includes data collection of size structure of the catches, 1985-2001.
Length Cohort Analysis and Yield-per-Recruit analysis were used to assess the status of the stocks in the area.
STOCK STATUS:
The species is considered to be fully or underexploited, depending on the fishing grounds exploited by the different fishing fleets with different rates. Catch rates showed in general positive trends during the last ten years. The current level of effort and fishing pattern looks adequate in order to warrant the sustainability of the resource and fishery.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
No specific recommendation
SCSA COMMENTS:
The SC endorses the assessment
Stock assessment of Mullus barbatus Geographical Sub Area 9 Ligurian and northern Thyrrhenian
FISHERIES:
Mullus barbatus is among the most commercial valuable species in the area and make part of a species assemblage that is the target of the bottom trawling fleets that operate near shore and a real target in some particular periods when the species in densely concentrated near the coast. It is caught mainly with three different variants of the bottom trawl net. Fishing pressure on the species changes in the different sub-areas of the Geographical Sub Area 9 depending on the consistency of the fleets that exploit the different grounds as well as on their traditional targets. Mullus barbatus catches are higher during the post-recruitment period (from September to November). About 150 vessels exploit the species. Annual landings are around 350 tonnes. Discard of undersized individuals is in general negligible, due to the fact that immediately after recruitment, small sized individuals are still concentrated inside the 3 miles stripe forbidden for trawling activities. However, some illegal captures do occur.
SOURCE OF MANAGEMENT ADVICE:
Data proceed from trawl-surveys (national and MEDITS programmes) as well as from Catch Assessment Surveys that includes data collection of size structure of the catches.
Length Cohort Analysis, Composite Production Models and Yield-per-Recruit analysis were used for assess the status of the stocks in the area. Assessments were performed separately for different operational units present in the area.
STOCK STATUS:
The species is considered fully exploited and in some areas overexploited, depending on the fishing grounds where the different fishing fleets operate with different levels of fishing effort. The current level of the Spawning Stock Biomass if compared with the pristine S.S.Biomass is considered too low, suggesting a risk of recruitment overfishing. Catch rates and total catches do not show any trend during the last ten years. However, standing stock size estimated through trawl-surveys suggests an increase in biomass of the species in most of the sub-areas.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
Management measures should include spatial and temporal closures, effort limitation, a minimum landing size, gear modifications, quotas and market restrictions. A total closure of the 3 miles in order to protect juveniles immediately after recruitment is recommended.
SCSA COMMENTS:
The SC endorses the assessment
Since the WG recommendations were too general, the SC discussed the recommendation of a reduction of fishing effort especially on the areas and season where and when recently recruited juveniles are concentrated. This can be obtained through the enforcement of a seasonal fishing ban of a period during the late summer and early autumn. This management measure should also produce a shift in the size of first capture.
Stock assessment of Aristeomorpha foliacea Geographical Sub Area 11 Sardinia
FISHERIES:
Red shrimp Aristaeomorpha foliacea is caught only by deep water trawling. In the last twelve years an increase from 59 to 70 trawlers fishing on red shrimps was observed in the geographical sub-area.
SOURCE OF MANAGEMENT ADVICE:
The assessment was carried out by Relative Y/R analysis using exploitation rate (E) as indicator of fishing effort. Data were collected during trawl survey programs. The current level of E was derived from Z and M estimates
STOCK STATUS:
According to this analysis the current value of E is very close to Emax.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
No management advice was given.
SCSA COMMENTS:
The SC endorses the assessment and recommends not to increase the effort.
Stock assessment of Merluccius merluccius in Geographical Sub Area 7, Gulf of Lions
FISHERIES:
Hake (Merluccius merluccius) is one of the most important demersal species of commercial fisheries in the Gulf of Lions. In 2001 it was exploited by 113 French trawlers, 95 French gillnetters, 26 Spanish trawlers and 20 Spanish longliners.
The catches of the trawlers are mainly composed of juveniles living on the continental shelf, while gillnetters and longliners are exploiting the adult part of the stock (spawners) living on the slope and in non trawlable areas.
80% of the landings are done by the trawlers; the total landings remained quite stable during the period 1988 (2941 tonnes) to 2001 (2693 tonnes). During the same period, the total number of trawlers decreased from 196 to 139, while the number of gillnetters increased from 20 to 95 and the longliners fleet increased from 13 to 20 boats.
During some periods, discards can represent a significant part of the total European hake catch, both in weight and in number
SOURCE OF MANAGEMENT ADVICE:
Stock assessment of the French-Spanish shared stock of hake (Merluccius merluccius) in the Gulf of Lions: a comparative approach. French-Spanish Working Group (IFREMER - IEO - CMIMAICM)
Length cohort analysis (LCA) and yield per recruit analysis (Y/R) were developed on a mean pseudocohort (1998-2001). The results have been compared to a previous similar analysis for the period 1988-1991. The objectives where to analyse hake dynamics in the Gulf of Lions and to compare its exploitation pattern and exploitation rate over a 10 years period.
STOCK STATUS:
General status of resource: Growth overexploitation
The biomass values showed a decreasing trend from 1988-91 to 1998-01 periods, but remained stable from 1998-00 to 1998-01.
Current biomass is 2.37% of virgin biomass; For females, if Fcurrent is reduced by 82%, Y/Rmax would be 3.3 times higher the current value. For males, if Fcurrent is reduced by 68%, Y/Rmax would be 1.6 times higher the current value.
There is a risk of recruitment overexploitation. Spawning females in the current stock have been estimated around one million of individuals, in comparison to 20 millions of individuals in the virgin stock. It seems that the spawning stock is decreasing in comparison to previous analysis (1988-91).
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
To avoid recruitment overfishing:
Reduce the effort of longline and gillnets in order to increase (or at least maintain) the SSB. Reduction of fishing effort could be achieved by establishing temporal closures for longline and gillnet during the period of maximum spawning, or by reducing time at sea, and/or fishing boats or/and engine power.
To reduce growth overfishing:
A transition analysis performed shows that the improvement of trawl selectivity is the most appropriate management measure (length at first capture fixed at 20 cm TL). Moreover, the reduction of fishing effort could be also considered: from the Y/R analysis, a reduction of about 80% of F should be necessary to reach the maximum Y/R at the current fishing pattern, but taking into consideration the short database, a reduction of 20% is recommended. This reduction is still far from the biological optima of the stock.
Reduction of fishing effort could be achieved by establishing temporal closures for longline and gillnet during the period of maximum spawning, or by reducing time at sea, and/or fishing boats or/and engine power.
It should be considered that the effort reduction or selectivity improvements imply losses at short term but gains at medium term.
SCSA COMMENTS:
The SC endorses the assessment and the recommendations. Both alternatives, decreasing effort and increasing length at first capture are independent and complementary management measures to reach the objectives.
Stock assessment of Aristeus antennatus in Geographical Sub Area 1,5 and 6, Northern Alboran Sea, Balearic Island and Northern of Spain
FISHERIES:
The red shrimp (Aristeus antennatus) is one of the most important resources of bottom trawling in the Balearic Islands. It is fished on the slope between depths of 400 to 800 m. In biomass, it represents an average of 5% of the overall catches, but its economic value is 30% of the total earnings of the fishery. The trawl yields varied between 3 and 14 kg/h. The highest yields occurred in winter and spring. The decline of the sizes at first capture in 1997 and the increase of juveniles in the catches can be interpreted as a change in the fishery strategy, which has increased the exploitation effort on the small sizes.
Landings in the three Geographical Sub Areas considered were between 100 and 150 t by each zone (landings at 6 sampling ports, representing around 80% of the red shrimp catch). Mean CPUE varied from 25 to 45 kg per vessel and day. Mean catch size oscillated between 28 and 32 mm CL and 22 and 25 mm CL for females and males respectively. Whilst the mean stock sizes were around 28-30 and 20-22 mm CL for females and males, age was close to one year for both.
SOURCE OF MANAGEMENT ADVICE:
Assessment of the exploited resource was carried out using length and age based methods (LCA and VPA) and yield per recruit analysis (Y/R). The interanual variability wasinvestigated studying the years 2000 and 2001.
STOCK STATUS:
The VPA revealed that the mean age of the catch was greater than the mean age of the stock, however, the Y/R curves in all areas pointed to an overfishing scenario. Moreover, a very high fishing effort on the spawning stock biomass was detected.
WG MANAGEMENT ADVICE AND RECOMMENDATIONS:
The Working Group recommends that the optimum effort should be half of the current fishing effort on females and three quarters of the current fishing effort on males.
SCSA COMMENTS:
The SC endorses the assessment.
The SC recommends the Demersal WG combine assessments for males and females in order to have an assessment of the stock as a whole and give an advise on it.
SAMED assessment results in the Northern coasts of the Mediterranean Sea
The source of the management advices is from SAMED EU Project that analysed and elaborated the data collected by MEDITS EU project at Mediterranean scale, using common and standardised methodology and procedures as far as the abundance indices, the demographic structure and parameters of the population at sea are concerned. Status of the Merluccius merluccius, Mullus barbatus and Nephops norvegicus stocks was assessed on the time series from 1994 to 1999 using two main reference indicators: the total mortality (Z) versus natural mortality (M) and a trend of the abundance indices (number and weight per km2).
Merluccius merluccius
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|
1 |
Northern Alboran Sea |
|
0/- |
6 |
Northern Spain |
|
+/+ |
7 |
Gulf of Lions |
|
0/+ |
8 |
Corsica Island |
|
0/- |
11 |
Sardinia |
|
+/+ |
9-10 |
Ligurian and Tyrrhenian Seas |
|
+/+ |
10 |
North Sicily |
|
-/- |
15-16 |
South of Sicily |
|
-/- |
19 |
Western Ionian Sea |
|
0/(-) |
18 |
Southern Adriatic Sea |
|
-/- |
17 |
Northern Adriatic Sea |
|
-/0 |
20 |
Eastern Ionian Sea |
|
+/(+) |
22 |
Aegean Sea |
|
+/(+) |
23 |
Crete Island |
|
-/+ |
In the first column, the black square
() indicates the Geographical Sub Areas
where the instantaneous coefficient of total mortality (Z), calculated on the
female fraction of the stock, is higher than twofold the corresponding natural
mortality coefficient (M). Both coefficients were considered invariant in time
(equilibrium assumption) and size (i.e., no variation by size class).
In the second column a rough trend (1994-1999) analysis of the density indices (loge transformed mean of individuals/km2 vs. years) is reported: the first item indicates the shelf, the second one the slope. The symbols 0, +, -indicate a stable, increasing and decreasing tendency respectively. The symbol in parenthesis indicates that the correlation was significant (p<0.05).
In almost all the Geographical Sub Areas, the total mortality of the population at sea was considerably higher than twofold the natural mortality, indicating a situation of intense exploitation. The tendency of the abundance indices on the shelf and slope indicates a decreasing, although not significant, trend in several Geographical Sub Areas. This outcome, coupled with the level of the total mortality, would indicate a more critical situation for those hake stocks, while the increasing density indices in other Geographical Sub Areas mitigate the judgement on the condition of the stocks. In the examined period, none decreasing tendency of recruitment indices, as possible indicator of recruitment overfishing, was detected and stable nursery areas were identified. Even considering the limited sampling time and an higher avoidance ability to the bottom trawl by large size hake, a very low presence of full mature females was found, raising some concern about the buffering capabilities of the Mediterranean hake stocks. Globally a growth overfishing for the species can be assumed.
SAMED MANAGEMENT RECOMMENDATIONS:
Temporal closure of the identified hake nursery areas.
Trawling effort limitation in space and time could be useful for the hake and the other species of the fishing assemblages. Some "input" limitation (i.e., number of hooks and gillnet hauled) should also be introduced in the long line and gillnet fisheries.
Mullus barbatus
Geographical sub-areas |
|
|
|
1 |
Northern Alboran Sea |
N.A. |
- |
6 |
Northern Spain |
|
- |
7 |
Gulf of Lions |
|
+ |
8 |
Corsica Island |
|
0 |
11 |
Sardinia |
|
- |
9-10 |
Ligurian and Tyrrhenian Seas |
|
(+) |
10 |
North Sicily |
|
- |
15-16 |
South of Sicily |
|
+ |
19 |
Western Ionian Sea |
|
- |
18 |
Southern Adriatic Sea |
N.A. |
+ |
17 |
Northern Adriatic Sea |
|
+ |
20 |
Eastern Ionian Sea |
|
(+) |
22 |
Aegean Sea |
|
+ |
23 |
Crete Island |
|
(+) |
In the first column, the black square
() indicates the Geographical Sub Areas
where the instantaneous coefficient of total mortality (Z), calculated on the
female fraction of the stock, is higher than twofold the corresponding natural
mortality coefficient (M). Both coefficient were considered invariant in time
(equilibrium assumption) and size (i.e., no variation by size class).
N.A. indicates that the estimate is not available for the Geographical Sub Area as the species did not comply in that area with the constraints imposed by the SAMED protocols for the evaluation of demographic parameters.
In the second column a rough trend (1994-1999) analysis of the density indices (loge transformed mean of individuals/km2 vs. years) is reported. Only the figures corresponding to the "shelf" macrostratum (10-200 m) are indicated considering the depth distribution pattern of the species.
The symbols 0, +, - indicate a stable, increasing and decreasing tendency respectively. The symbol in parenthesis indicates that the correlation was significant (p<0.05).
In the most part of the Geographical Sub Areas, the total mortality of the population at sea was considerably or moderately higher than twofold the natural mortality, indicating a situation of intense or at least full exploitation. The areas where both the information (high total mortality and negative density index trends) are converging should be considered with more caution, while the increasing density indices in other Geographical Sub Areas mitigate the judgement on the condition of the stocks. Bottom trawl surveys were generally carried out during the spawning season of the species, thus abundance is mainly referred to the "adults". This could imply that despite of the high total mortality the self renewal of the stocks is not compromised in some areas.
Excluding the Gulf of Lions and Corsica, globally a full exploitation and a growth overfishing, according to the Geographical Sub Areas, can be assumed for the species.
SAMED MANAGEMENT RECOMMENDATIONS:
Maintaining the protection of the shallow waters, where the recruitment occurs (depth or distance from the coastline, depending on the shelf characteristics), along the year.
Temporal closure of the fishery accounting for both the recruitment of red-mullet and of the movements of recruits from shallower to deeper waters (mainly in the early autumn in the Western and Central Mediterranean) appear as crucial for delaying the time of the recruitment to the gear.
Nephrops norvegicus
Geographical sub-areas |
|
|
|
1 |
Northern Alboran Sea |
N.A. |
+ |
6 |
Northern Spain |
|
- |
7 |
Gulf of Lions |
|
+ |
8 |
Corsica Island |
|
+ |
11 |
Sardinia |
|
0 |
9-10 |
Ligurian and Tyrrhenian Seas |
|
+ |
10 |
North Sicily |
N.A. |
+ |
15-16 |
South of Sicily |
|
0 |
19 |
Western Ionian Sea |
N.A. |
(+)/0 |
18 |
Southern Adriatic Sea |
|
0/0 |
17 |
Northern Adriatic Sea |
|
+/- |
20 |
Eastern Ionian Sea |
|
(-) |
22 |
Aegean Sea |
|
- |
23 |
Crete Island |
N.A. |
0 |
In the first column, the black square
() indicates the Geographical Sub Area
where the instantaneous coefficient of total mortality (Z), calculated on the
female fraction of the stock, is higher than twofold the corresponding natural
mortality coefficient (M). Both coefficient were considered invariant in time
(equilibrium assumption) and size (i.e., no variation by size class).
N.A. indicates that the estimate is not available for the Geographical Sub Area as the species did not comply in that area with the constraints imposed by the SAMED protocols for the evaluation of demographic parameters.
In the second column a rough trend (1994-1999) analysis of the density indices (loge transformed mean of individuals/km2 vs. years) is reported. Only the figures corresponding to the "slope" macrostratum (201-800 m) are indicated considering the depth distribution pattern of the species, except for the Geographical Sub Areas 2.1.a, 2.2.b and 2.2.c where the species occurred, although with lower density, on the shelf (10-200 m depth) too.
The symbols 0, +, - indicate a stable, increasing and decreasing tendency respectively. The symbol in parenthesis indicates that the correlation was significant (p<0.05).
In the most part of the Geographical Sub Areas the total mortality of the population at sea was slightly or moderately higher than twofold the natural mortality, indicating a situation of slight overexploitation or a full exploitation. The areas where both the information (high total mortality and negative density index trends) are converging should be considered with more caution, while the increasing density indices in other Geographical Sub Areas mitigate the judgement on the condition of the stocks.
The known behavioural characteristics of this species (large periods of time inside the burrows, from which it emerges periodically giving rise to diurnal and seasonal fluctuations in the catches) makes it less vulnerable than other species to the fishing pressure. Not withstanding patchiness in population structure and density dependence phenomena could be related with cases of "local" or "stock-let" overexploitation.
SAMED MANAGEMENT RECOMMENDATIONS:
Technical improvement of the gear that avoid the capture of the small size norway lobster and reduce the impact of otter trawl doors on the bottom and the "scrapping" capability of the gear.
The complete documents are available at ftp:\cucafera.icm.csic.es\pub\scsa
[2] As extracted from the
report of SCSA, Barcelona, Spain, 6-10 May 2002. |