I Mosqueira

Haritz Arrizabalaga

Duncan Robertson

F Garibaldi

A Mariani

Natacha Nikolic

S Saber

Jorge Ortiz-De-Urbina

V Ortiz De Zarate

G Tserpes

Scientific, Technical and Economic Committee for Fisheries (STECF) -European data for North Atlantic and Mediterranean albacore

Keywords: technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

SCIENTIFIC, TECHNICAL AND ECONOMIC COMMITTEE FOR FISHERIES (STECF) -European data for North Atlantic and Mediterranean albacore (STECF-17-03)

The report of the Expert group held during [START_REF]Report of the Standing Committee of Research and Statistics[END_REF][14][15][16] March 2017 was reviewed during the STECF plenary meeting held in Ispra, Italy, 27-31 March 2017.

Request to STECF

STECF is requested to review the report of the STECF Expert Working Group meeting, evaluate the findings and make any appropriate comments and recommendations.

STECF response STECF comments

The European Union is the main producer of albacore tuna in the Mediterranean and the North Atlantic, catching 90% and 80% of the total catch of each of the stocks during the last decade, respectively. Thus, the EU has a particular responsibility for the provision of good quality data for these stocks. However important data gaps, concerns on data quality and a lack of relative abundance indices exist for the Mediterranean albacore. In consequence, the stock assessment relies on data poor methods and is the only major tuna stock at ICCAT that currently lacks an estimate of MSY (ICCAT, 2016). In addition, scientists from the main EU fishing countries do not participate in the stock assessment process, making it difficult for the group to interpret the data available in ICCAT datasets and to make decisions around those.

Regarding the North Atlantic albacore, data gaps are minor. The main issue is that the available indices of abundance are noisy and often show opposite trends.

The ICCAT albacore tuna working group as well as the Standing Committee for Research and Statistics have drafted many recommendations to try to improve the situation. The last assessment of the Mediterranean stock was conducted in 2011, and the next stock assessment will take place between 5 th to 9 th of June 2017, so it is important to address these ICCAT recommendations by then, to the extent possible.

The EWG 16-19 on European albacore tuna data met in March 2017 in order to (i) review the completeness of EU data in ICCAT datasets, (ii) identify available Mediterranean data not submitted to ICCAT, (iii) review the new abundance index for the French mid water trawl fleet, (iv) explore additional data sources to improve the situation regarding indices of abundance and (v) identify available information on bycatch species in albacore fisheries.

The STECF considers that all ToRs were properly addressed by the EWG, which achieved some significant outcomes. Regarding the Mediterranean stock, the EWG focussed mostly on data from Italy (which caught around 60% of the total catch during the last decade) and identified additional information, mostly biological data, that would be useful for the ICCAT working group.

The STECF plenary compiled a more complete set of information regarding the data collected by Italy under DCR/DCF during 2003-2015 (Table 1). The STECF noted that in the ICCAT database there is no effort information before 2009. The data identified in ICCAT also recommended splitting the catch assigned to "unclassified" gears (mostly for Italy and Greece). The identified dataset for Italy will also be helpful for this task. According to the EWG, unfortunately there is no data for Greece in the past on gear specific landings, but expert knowledge could be used to accomplish this task.

The STECF acknowledges the availability of biological data for Italy that might allow to substantially improve the biological parameters (growth, maturity and length weight relationship) used by the ICCAT albacore tuna working group. However, STECF notes that similar data are also available in other countries (e.g. Spain, Cyprus, Greece). The STECF considered therefore most appropriate to conduct a joint analysis of all the datasets, to estimate a maturity ogive, a growth model and a length weight relationship that represents the whole stock.

Regarding the North Atlantic stock, the STECF welcomes the catch and effort data collected for the French mid water trawl fleet (one of the main fisheries targeting the stock, with 15% of the total catch during the last years), and the derived relative abundance index. The new data are already submitted to ICCAT and incorporated into the datasets. The new index is comparable to the baitboat index (the only EU index used in the last assessment), and the STECF recommends to present it in the next albacore meeting, for its consideration in future assessments. The STECF also welcomes the efforts made by Portuguese scientists to use swordfish targeting longline fishing operations as a potential source of albacore relative abundance information. Given the wide geographic extension of these longline operations, substantially overlapping with the North Atlantic albacore tuna distribution, the STECF encourages that efforts continue to standardize these data. Moreover, and considering the low amount of albacore caught by this fleet, it would be desirable to extend these efforts to the Spanish longline fleet.

STECF conclusions

The STECF recommends DGMARE to make sure that, in order to improve the EU data and participation issues identified by ICCAT for Mediterranean albacore, the following actions are taken by Member states before the next stock assessment to be conducted between 5 th and 9 th of June:

-Submit to ICCAT, following official formularies, the Italian Task 2 data (catch, effort and size disaggregated in time and space) collected under the DCF and DCR, for the missing years. This involves primarily effort data for the period 2004 to 2008. However, a complete revision of all the Italian Task 2 data series is also recommended to address ICCAT concerns on data quality. -Disaggregate the task 1 (total annual catch) data associated to "unclassified" gears for Italy (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) and Greece (1996Greece ( -2002)), and submit a gear specific Task 1 revision to ICCAT.

Additionally, STECF encourages the following actions

-To conduct a joint biological analysis for Mediterranean albacore, using data collected through DCR/DCF by the different Member States on maturity, growth and length-weight relationship, to update the biological parameters used for this stock at ICCAT. -Assure participation of EU scientists from the most relevant Member States in albacore landings (Italy, Greece, Spain and Cyprus) in the forthcoming stock assessment, providing standardized cpues for their fisheries and contributing to the understanding of the fisheries and stock dynamics.

Regarding the North Atlantic albacore stock, the STECF acknowledges the recent improvements regarding task 2 data for the French mid water trawl fishery and supports that the newly developed relative abundance index for this fishery is presented to the ICCAT albacore working group. Likewise, in the longer term, the STECF suggests to continue exploring the possibility to obtain relative abundance of albacore tuna using swordfish oriented longline fishing operations by Portugal and Spain.

Contact details of STECF members

1 -Information on STECF members' affiliations is displayed for information only. In any case, Members of the STECF shall act independently. In the context of the STECF work, the committee members do not represent the institutions/bodies they are affiliated to in their daily jobs. STECF members also declare at each meeting of the STECF and of its Expert Working Groups any specific interest which might be considered prejudicial to their independence in relation to specific items on the agenda. These declarations are displayed on the public meeting's website if experts explicitly authorized the JRC to do so in accordance with EU legislation on the protection of personnel data. For more information: http://stecf.jrc.ec.europa.eu/adm-declarations This report does not necessarily reflect the view of the STECF and the European Commission and in no way anticipates the Commission's future policy in this area

EXECUTIVE SUMMARY

The scientific bodies of the International Commission for the Conservation of Atlantic Tunas (ICCAT) have in the past noted shortages and problems with the data on the activities of the European fleets on the stocks of North Atlantic and Mediterranean albacore, Thunnus alalunga, [START_REF] Anon | Report of the Standing Committee of Research and Statistics[END_REF](Anon. , 2012a[START_REF] Scrs | Report of the 2011 ICCAT South Atlantic and Mediterranean Atlantic and Mediterranean Albacore Stock Assessment Session[END_REF](Anon. , 2014a(Anon. , 2014b[START_REF] Anon | Report of the 2013 ICCAT North and South Atlantic Albacore Stock Assessment meeting[END_REF](Anon. , 2016a[START_REF] Anon | Report of the 2016 ICCAT North and South Atlantic albacore stock assessment meeting[END_REF].

Given the upcoming session of ICCAT Working Group on Albacore (WGA), which is scheduled to attempt an evaluation of the status of the stock of Mediterranean albacore, and the results of last year's stock assessment of North Atlantic albacore [START_REF] Anon | Report of the 2016 ICCAT North and South Atlantic albacore stock assessment meeting[END_REF], this EWG was tasked with investigating possible solutions for the problems that have been identified.

Under the current CFP, EU member countries must collect data of the activities of their fishing fleets, as well as that necessary for the estimation of biological parameters of the stocks under exploitation. Furthermore, the Data Collection Framework establishes the overarching mechanism by which coverage and precision levels on data collection are to be achieved.

At the same time, contracting parties of the International Commission for the Conservation of Atlantic Tunas (ICCAT) must report data on the activities of fleets under their flag to allow its Scientific Committee of Research and Statistics (SCRS) to conduct the necessary analyses and evaluations of stock status, to then be able to provide sound scientific advice for the management of those fisheries. The two stocks considered by EWG 16-19, North Atlantic and Mediterranean albacore (Thunnus alalunga), are under the remit of ICCAT's mandate. In both cases, most of the catches are taken by fleets operating under EU flags, so the EU has a particular responsibility for the provision of good quality data for these stocks.

The EWG was asked to work on a number of issues on data quantity and quality that had been identified by the relevant bodies of ICCAT: the Working Group on Albacore (WGA), and the SCRS. In summary, for the North Atlantic the data gaps are minor, but the available relative abundance series are noisy and sometimes controversial, while in the case of the Mediterranean, there are important information gaps, as well as lack of relative abundance indices appropriate for stock assessment.

A new dataset of catch and effort for the French pelagic trawl fleet, according to the requirements of ICCAT Task 2 database, has been assembled through an specific contract for this meeting and then reviewed by the group. This dataset is in the process of being submitted to ICCAT for incorporation to the Task 2 (T2CE) dataset. The standardized CPUE time series for this fleet was reviewed as a potential index of abundance for North Atlantic albacore and recommended for consideration by WGA.

Previously identified shortages and absences of data from EU fleets were reviewed and possible sources of information that could be used to complete and ameliorate them have been identified and listed. The work required to carry out these corrections will need to be conducted by scientists with the necessary knowledge of the fisheries involved and of the specific arrangement under which the data has been collected.

A particular issue has been identified with biological data collected by Italy under the current DCF.

While biological data (age, length-weight, maturity and sex ratio) appears to have been collected and reported back to the relevant authority, it is not being made available for interested scientists, nor presented to ICCAT scientific bodies. Data has been collected in 2010, 2013 and 2016, although the later is still to be submitted. The EWG considers that an appropriate mechanism (e.g., an specific data call followed by an analysis of the data by a qualified scientist) needs to be considered to make all data on the biology of Mediterranean albacore collected under the DCF quickly available so it can be used to inform the upcoming stock assessment of Mediterranean albacore by WGA, scheduled for June 2017. This analysis should try to utilize the full these dataset to obtain a better estimate of biological parameters for the stock.

In the longer term, a data-mining exercise on data collected on Mediterranean albacore on behalf of the Italian authorities in the past should be considered. Data collected under the Data Collection Regulation (DCR) was submitted and stored by the national administration, and should have also been kept at each of the seven operational units along the Italian coast in charge of this task at that time. Additional data collected under a range of national or European research projects could be available, and could also be assembled through this exercise. Some Italian data presented in the past to ICCAT meetings has been partly incorporated to the ICCAT datasets, but it would be necessary to fully review this process. The feasibility of the exercise could be first assessed through contacts with the relevant authorities and scientists, so as to get an indication of the quantity of data and the storage format in which it could be found. Such a study, together with a review of published sources of information, some of it having originated from the same data collection programs, has the potential of assembling a much richer dataset for this stock and fishery.

Given the relative scarcity and dispersion of information for the Mediterranean albacore stock, it appears reasonable that greater integration of data could improve our knowledge on its biology and dynamics. Particularly, biological parameters are being estimated at several locations from limited sampling efforts and analysed in isolation. The organization of a network of relevant scientists could help ameliorate this problem.

The discrepancy between the data submission requirements of various Regional Fisheries Management Organizations, such as ICCAT, and those contemplated in the European data collection regulations was noted by the EWG. Some of the European fleets catching albacore are not currently collecting data on, for example, the size distribution of the catches, which ICCAT requires, given that they are responsible for a low percentage of the total catches of the stock.

The use of data, specially catch rates, from fleets operating in the North Atlantic, which catch albacore in small numbers, but which have a large spatial coverage, was indicated as a possibly relevant source of information on trends in abundance for the stock. A preliminary analysis of one such fleet, Portuguese longliners targeting swordfish, was reviewed, and found to be potentially useful at providing some context for the analysis of changes in spatial distribution of the stock and the effect this process might be having on other CPUE series, but also for obtaining an abundance index covering a larger proportion of the area occupied by the stock. Unfortunately, the coverage of the observer program is limited, which might compromise the standardization of the CPUE, but further analysis will be required, including a possible comparison with similar fleets, to really assess the utility of these data.

In relation to the information available on by-catch obtained by the European fleets targeting North Atlantic and Mediterranean albacore, the currently available sources of information have been listed and reviewed. Although there is at least some information for the main gears, it is mostly limited to the by-catch and discards of commercial species, and there is limited information to understand spatio-temporal patterns of by-catch in the European fisheries targeting albacore tuna.

INTRODUCTION

The meeting of STECF Expert Working Group 16-19 took place at the European Commission Joint Research Centre (JRC), in Ispra, Italy, between the 13 and 16 March 2017, and was attended by ten experts (nine on site and one remotely).

TERMS OF REFERENCE TO THE EXPERT GROUP

The ToRs for this EWG were set as follows: The EWG revised the completeness and utility of the EU data in ICCAT, as highlighted in ICCAT data catalogues for North Atlantic and Mediterranean stocks, as well as the recommendations related to EU statistics that the Working Group on Albacore and the SCRS have made since 2010 [START_REF] Anon | Report of the Standing Committee of Research and Statistics[END_REF](Anon. , 2012a[START_REF] Scrs | Report of the 2011 ICCAT South Atlantic and Mediterranean Atlantic and Mediterranean Albacore Stock Assessment Session[END_REF](Anon. , 2014a(Anon. , 2014b[START_REF] Anon | Report of the 2013 ICCAT North and South Atlantic Albacore Stock Assessment meeting[END_REF](Anon. , 2016a[START_REF] Anon | Report of the 2016 ICCAT North and South Atlantic albacore stock assessment meeting[END_REF]. The work plan for 2017 of the Working Group on Albacore also includes issues related to EU data, which were identified as key tasks to be conducted within this year (Anon. 2016a).


ICCAT contracting parties, and by extension the relevant EU member countries, are requested to submit two main sources of data:

 Task 1 (T1) total nominal catch per year.

 Task 2 (T2) divided in T2CE, catch and effort, and T2SZ, size information, both of them disaggregated by 1ºx1º or 5ºx5º geographical squares, and month or quarter.

The ICCAT data catalogues rank each fishery according to the proportion of the total catch they take, and then analyse the coverage of Task 2 data, which can be used to identify the most relevant data gaps.

North Atlantic albacore

The North Atlantic data catalogue shows that nearly 90% of the total yield is caught by only seven fleets (EU-Spain BB and TR fleets, Chinese Taipei LL, EU-France TW and GN, EU-Portugal BB, and EU-Ireland TW). Six of them are EU fleets, and their T2CE and T2SZ series are almost complete for the last 15 years. EU-France TW data has recently been submitted to ICCAT.

According to the 2017 work plan of the ALB WG, and following standard protocols, there is a need to document the changes with respect to previous submissions, so that it is clear what needs to be replaced in the ICCAT database. There are some minor gaps in T2CE and T2SZ series (EU-France TW, EU-Portugal BB and, EU-Ireland TW), however the EWG identified that size data is actually being submitted, albeit in a different format, with the agreement of ICCAT. The data catalogue should reflect this in future editions.

The EU-Ireland gillnet fleet is not operating currently, but used to be a major fishery before 2002, and lacks most of the T2 data during the time series. The EWG found that these data are probably not available.

Other less important fisheries with important gaps include EU-Spain longline fisheries targeting swordfish, for which effort and size information remains unavailable for the 1998-2015 period.

The EWG noted that some observer information might be available to fill this gap.

Given the lack of fisheries independent information, relative abundance series based on standardized CPUE are essential for the stock assessment. The current base case, based on a surplus production model, includes a single EU index (by Spanish baitboats), and four other longline indices by non-EU fleets. The French troll and Irish mid water trawl indices are relatively short and noisy and are not considered in the assessment. The French MWT index produced becomes a new candidate for the next assessment.

Overall, the available EU indices are quite noisy, with some year to year inconsistencies (e.g. within mid water trawl fleets, or between baitboat and midwater trawl indices). In terms of trends, baitboat and MWT data show somewhat upward trends during the last years, unlike the troll index that shows a slightly downward trend. The WGA acknowledged that, for migratory species like albacore, CPUE series very often reflect local abundance, and as such, discrepancies among them can be expected, but overall they should reflect general trends of the whole stock. However, in the EU case, although these indices come from a similar but not completely equivalent area, they do not appear to provide a clear picture of the relative abundance trends in the NE Atlantic (Anon. 2016b).

Mediterranean

The data catalogue of Task 1 versus Task 2 for Mediterranean albacore shows that Task 2 information is really sparse and incomplete for both, catch & effort and size data (Figure 3). With the exception of the Spanish BB, LL and TR fleets, and the Cyprus LL in recent years, very little and usually highly sparse information exists for the main Italian fleets (LL, PS, GN) and Greek fleets (LL, HL). The WG identified some EU albacore catch, effort, and size data, available from scientific reports and grey literature, which do not seem to be included in the ICCAT database. These include [START_REF] Marano | AdriaMed Drifting longline fishery in the southern Adriatic Sea (GFCM Geographical Sub-Area 18)[END_REF] There are only three standardized CPUE indices for this stock, namely the ones derived from the Greek and Spanish longline targeting albacore and the Greek swordfish fishery with albacore bycatch. These series are generally short, fragmented, and often contradictory (Figure 4). In this situation, the WGA also considered nominal CPUE series (from two Italian longline and one Spanish sport fisheries) as potential sources of information in its last analysis of this stock [START_REF] Scrs | Report of the 2011 ICCAT South Atlantic and Mediterranean Atlantic and Mediterranean Albacore Stock Assessment Session[END_REF]. As part of the work plan for 2017, where the stock status will be updated, it is required to update all six indices and, if possible, enlarge the time series or produce new ones.

Figure 3: SCRS catalogue on statistics (Task-I and Task-II) for Mediterranean albacore by major fishery (flag/gear combinations ranked by order of importance) and year (1995 to 2015). Only the most important fisheries (representing ±97.5% of Task-I total catch) are shown. For each data series, Task I (DSet= "t1", in tonnes) is visualised against its equivalent Task II availability (DSet= "t2") scheme. The Task-II colour scheme, has a concatenation of characters ("a"= T2 catch/effort exists; "b"= T2 size exists; "c"= Catch at size exists) that represents the Task-II data availability in the ICCAT database.

UN t2 -1 -1 -1 -1 b -1 b b -1 -1 -1 -1 -1 -1 4 ALB

Table3. ALB-M stock

The information about basic biological parameters (such as growth, length/weight relationship and maturity) is also fragmented, with different studies that have been carried out throughout the Mediterranean, generally with limited samples sizes (Anon., 2012a). Thus, the EWG recommends integrating the various biological studies for Mediterranean albacore, and performing joint analyses on the original datasets from the various studies that have been published so far.

Considering that biological data have been likely collected in different data collection programs (e.g. DCR, DCF, research studies) and thus under different methodologies, it is recommended that a concerted effort be made to consolidate these data in an appropriate form for analyses.

Last, participation in the stock assessment process of Mediterranean albacore from countries with important fisheries has been poor. This has limited the ability of the WG to interpret the data and conduct the analyses. Thus, the ALB WG has reiterated the need for experts from countries with important fisheries to participate in the stock assessment process of ICCAT. The EWG encourages STECF to request that the presence of European scientists with knowledge on these fisheries at the ICCAT WG meetings is facilitated.

Figure 4:

Available CPUE series scaled to the mean of each series, for the Mediterranean albacore stock. The two Greek series as well as the Spanish longline index are standardized, while the rest are nominal series.

ASSESSMENT OF THE QUANTITY AND QUALITY OF DATA AS EXPECTED UNDER CURRENT DCF

REQUIREMENTS

Considering the current data shortages detected in the ICCAT catalogue, especially in the Mediterranean stock for the Italian and Greek fleets, the EWG considered alternative data sources that could help alleviate these problems.

In the case of Greece, it is considered feasible to use expert knowledge for the allocation of unclassified gear catch into specific gears. However, the DCF was not operative in Greece for several years and the EWG was unable to identify DCF data that might be useful to improve the Task 2 (CE) situation for Greece. The only data source the EWG was made aware of is a dataset compiled in the MAREA Project -MEDPEL (Catches of pelagic (drifting) longline fisheries in the Mediterranean, SC No 6 (SI2.635542)MARE/2009/05-Lot 1), where size and effort information for the longline fishery targeting albacore were collected for Greece in the Eastern Mediterranean for the years 2004-2006.

In the case of Italy, the EWG was unable to identify scientific data sources that would allow separation of the unclassified catch, or to eventually correct the extraordinary large sizes of fish reported in 2003, although it is not clear if this information might exist in some format in the central repository of the Italian Ministero delle politiche agricole alimentari e forestali (MIPAAF).

In addition to this, and for the Italian Task 2 (CE and SZ) data, the EWG identified the following potential data sources:

-Research projects funded by Italian Ministry on Large pelagics in the framework of Fishery multiannual plans: 1985 -1989, 1990-1993, 1994-1995, 1997-2000, 2001-2004, 2004-2006 and DCR. The Operational Units for these projects 1 or the central authority should be able to provide the data thus collected.

-Data collection under the DCF for the period 2007-2016. The Operational Unit is UNIMAR. Finally, in order to conduct comprehensive growth, length weight relationship and maturity studies throughout the Mediterranean, the EWG identified the DCF data as the most immediate way to gather the available data collected on biology every three years. A data call is suggested as a mechanism to assemble these data that would then need to be analysed by scientists before being presented to ICCAT WG on albacore, ideally in time for the upcoming stock assessment.

1 University of Genoa, University of Bari, University of Cagliari, Aquastudio, Laboratorio di Biologia Marina e Pesca di Fano (University of Bologna), Laboratorio provinciale di Biologia Marina of Bari, and University of Messina.

REVIEW THE NEW CATCH AND EFFORT DATASET OF NORTH ATLANTIC ALBACORE CAUGHT BY FRENCH MID-WATER TRAWL FLEETS

The EWG reviewed the report of an ad-hoc contract titled Preparation of new data from the North Atlantic albacore French mid-water trawling fisheries (Background document EWG-16-19 Doc 01) which presented a revised data series of catches at length and effort for this fleet.

New catch and effort dataset

A new dataset of catch and effort for this fleet has been extracted from the HARMONIE database system, covering the 1991 to 2015 period. It integrates data from various sources, including logbooks, observers, auction data and the French Fisheries Information System. The dataset has first been corrected for a number of errors and omissions, as summarized in Table 1.

Data Details of corrections Number of corrections Date of the fishing operation

Trip date and fishing operation date was inversed and hence corrected to be consistent.

10,944 lines

Latitude and Longitude Latitude and longitude are unknown (NA) for error typing, unknown or uncertain spatial statistical rectangles (e.g. 8.00; 7000; 8000; 007H00; 007J00; 007K00; 008A00; 008B00; 008C00; 008D00). 10 spatial statistical rectangles for a total of 354 lines

Catch per fishing operation

Inconsistent catches such as those above 36,000 Kg performed in a single fishing operation were removed from the database.

lines

Fishing times (hours) Fishing times (hours) reported on 24 hours for one fishing operation were corrected. The catches are never on 24 hours but 4 to 6 hours in average per night. Hence, these inconsistent fishing time were replaced with an average value known to limit the analysis errors.

lines

Latitude and Longitude Geographic points were on land and corrected from original files.

lines

Table 1: Corrections executed to the French mid-water trawl albacore fishery dataset .

This new dataset has now been assembled according to ICCAT's requirements and is in the process of being submitted for revision and incorporation into ICCAT Catch and Effort (Task 2) dataset.

CPUE series

A CPUE series for this fleet has also been produced through this contract that could be considered by ICCAT WG on albacore as an input for the next stock assessment of the stock. The nominal CPUE (Figure 5) appears to be influenced by the nature of this fishery, in which boats are driven to target albacore more strongly if fishing conditions for other stocks are not favourable. For example, the number of vessels of this fleet catching albacore went from 28 in 2004 to 121 in 2005, probably due to the closure of the Bay of Biscay anchovy fishery.

A preliminary standardization of the series has been carried out, considering the effects of year, month, area, Sea Surface Temperature (SST) and depth. A set of four models was assembled and compared (Table 2). Diagnostic scores, like AIC, were all very similar, and the simplest model (Mod1) was tentatively selected (Figure 6). The presented index (Figure 6) makes use of the entire time series of data available (1991 to 2015). The spatial distribution of catch rates (Figure 7) shows the known pattern of catches being higher in areas closer to the coast and along the continental shelf. The figure also shows the areas used in the CPUE standardization. The EWG considered that the effect of alternative area definitions could be explored in the future, maybe by looking at changes in the time series of the center of the distribution of catch rates. These could be expected to be related to the number of vessels operating in the fishery, which is highly variable by year.

Model

The EWG considered this dataset to be a very useful addition to the set of indices of abundance for this stock, especially given the relatively large area covered by this fleet when compared with others currently used in the stock assessment. Although the next stock assessment for this stock is only scheduled to be carried out by ICCAT in 2020, the EWG encouraged the author of the report to present these findings and the CPUE series to be next session of ICCAT Working Group on albacore tuna for discussion and further refinement.

ASSESS AVAILABILITY AND USEFULNESS OF DATA ON CATCHES OF NORTH ATLANTIC ALBACORE BY OTHER FLEETS

The EWG considered the suggestion by ICCAT Working Group on albacore tuna that catch and effort data for certain fleets not targeting albacore, but for which this stock is a by-catch, should be explored with a view at generating indices of abundance from standardized CPUE series. The interest if the WG focused on fleets covering a larger proportion of the potential area of distribution of North Atlantic albacore that those from which the current CPUE series are extracted. These series could potentially be less sensitive to changes in catch rates due to shifts in the spatial distribution of the stock being interpreted as changes in abundance, or could at least provide an indication of trends in spatial distribution under which to interpret the current indices of abundance. A document was reviewed by the EWG (Background document EWG-16-19 Doc 05), that included a preliminary CPUE series for the Portuguese longline fleet targeting swordfish.

The spatial coverage of this fleet (Figure 8) initially makes it a good candidate, although the catch of albacore tuna has generally been as low as 6.5 t in 2014.

The spatial distribution of the catches of albacore from this fleet appears to concentrate on a handful of spots when observed across the whole time series (Figure 9). The corresponding CPUE series must obviously interpreted with caution (Figure 10)

The EWG thanked the Portuguese researchers for their work and welcomed the analysis provided.

It is clear that the low level of observer coverage, from which the spatial location of the catches is inferred, is likely to affect the observed patterns. In some years, sets covered by on-board observers accounted for as little as 0.1% of the albacore catch. The EWG recommended that the spatial distribution of observed sets is used to assess possible biases in the estimates of spatial distribution of albacore catch rates. The extension of this exercise to other fleets operating in this area should still be considered, to better understand the amount of information that these dataset might contain on albacore stock and CPUE dynamics.

DISCUSS SOURCES OF INFORMATION ON CHANGES IN SPATIAL DISTRIBUTION OR FISHING

PATTERNS

The EWG revised the different standardized indices of abundance generated from the CPUE series of different EU fleets (Figure 2).

On the Spanish troll CPUE index, the group considered the information available to support the hypothesis that the catchability of this fleet might have decreased in time, as a result of less area being covered, affecting the detectability of the schools. Although there has been a decrease in the number Spanish TR boats in some regions of Spain, numbers have remained generally stable (Figure 11). It is not possible at this stage to infer clearly what effect these changes might have brought to the effective catchability of this fleet, where searching for schools tends to be improved by the number of areas and the area covered. Support for the hypothesis of decreasing catchability through time in this fleet, and its effect on the CPUE trends, remains open. These issues could be further understood, and eventually resolved, with a fine scale analysis including operational spatial distribution data, in a joint GLM. However, some potential problems for this were noted, such as the likely partial overlap of their spatial distributions, and mostly the different effort units used by different fleets, as well as the statistical distributions and properties of the catch per unit of effort. However, this joint analysis is likely to be feasible for the two MWT fleets, the Irish and the French. Still, the EWG noted that resolving inter-annual variation was not as high priority as the general trends showed by the indices, and that the French MWT index was in itself a good candidate to be presented to the WGA for future assessment of the North Atlantic albacore stock.

Further work was presented to the group in relation to environmental information (STECF ). This study presents a habitat model for North Atlantic albacore, incorporating information from the Basque troll logbook information for the period 1987-2006. The authors noticed a northward trend of both the historical and the future preferred habitat of albacore tuna, which might affect the long term trends in catchability. Besides, the authors proposed that yearly habitat predictions can be analysed together with the yearly spatial distribution of the fleets to have some insight regarding the relative availability of the response to different fleets, and help resolve the inter-annual discrepancies observed for different indices.

A presentation was made to the EWG on the spatial distribution of albacore catches caught by surface Spanish fleets in 2015 in the North East Atlantic and the Bay of Biscay. Data from monitored trips at main fishing landing ports were presented as monthly spatial distribution in relation to SST differences between the two fishing areas: Bay of Biscay and offshore waters of the North East Atlantic, for both the troll and bait boat fleets operating in these fishing grounds.

In 2015, the overall SST ranged from 16°C to 22°C. However there are differences concerning the strategy of the bait boat fleet confined to the Bay of Biscay, where a higher SST (19-22 C) were observed and the troll fleet operating on the offshore waters in North East Atlantic area, where lower temperature were observed. Juvenile albacore (age 1 group) entering the Bay of Biscay plays an important role (i.e. years 2011, 2012 and 2015) in the yield of bait boat fleet. The abundance of this age group should be a good indicator of a strong cohort in any given year. But our ability to interpret the trends in catch rates for this age group is limited by our understanding of the reasons behind both the dynamics of the migration of juvenile albacore, and of the operational decisions of this fleet. Both are likely to have strong impact in the quantity of information on stock dynamics contained in the CPUE series, and could introduce a biased view on abundance of the stock in the stock assessment model.

IDENTIFY SOURCES OF DATA ON MEDITERRANEAN ALBACORE OF USE FOR THE NEXT STOCK

ASSESSMENT

The EWG considered the data-related problems found in the last stock assessment session on Mediterranean albacore carried out by ICCAT in 2011 [START_REF] Anon | Report of the Standing Committee of Research and Statistics[END_REF][START_REF] Scrs | Report of the Standing Committee of Research and Statistics[END_REF], that have limited the ability of ICCAT to carry out a quantitative evaluation of the status of this stock.

A presentation was made to the EWG on the results of an ongoing study commissioned by the Italian MIPAAF titled "Scientific bases to support management Plans in the framework of the Common Fishery Policies"-UO "Description of fishing activities of albacore (Thunnus alalunga) to identify reference parameters for the stock management". Information on the activities of the longline fleets potentially targeting albacore was collected in 2015, including spatial and temporal distribution of effort, configuration of the gears being used, and definition of the fleet segments that more actively catch albacore. Scientific observers were also placed on a total of 30 trips, concentrated on four months of 2015, specifically dedicated to detect the presence of discards and by-catch species in the albacore fishery.

The data collected indicate that a limited number of vessels, around 20 boats from the Sicilian fleet, are responsible for approximately 70% of the Italian catches of albacore tuna. These boats follow albacore movements in the months between April/May and August/September, and it is in this period that the bulk of the Italian catches is concentrated.

The EWG considered this information to be of great value to better understand the dynamics of this fleet, responsible for a large share of the catches of this stock. It would desirable that the information collected is presented to the relevant scientific body of ICCAT once the project is completed.

Biological data

The results on some recent studies on the reproductive biology of albacore from the Western Mediterranean Sea were presented to the EWG (STECF EWG-16-19 Doc. 9). The size frequency, sex ratio, gonad reproductive stages, spawning season, minimum length at maturity and gonadosomatic indexes were examined. Only 5.4% of the 16,104 fish measured fell outside the length range of 60 to 90 cm fork length (FL). The sex ratio was female biased in fish <70 cm FL and male biased in those >75 cm FL. Histological analysis of the ovaries and the monthly variation of the gonadosomatic index for both sexes showed that spawning occurred from June to August. Only four immature individuals were found. The minimum length at maturity for albacore was 56 cm FL. Batch fecundity estimates ranged from 0.42 to 2.16 million oocytes (mean ± SD =0.98 ± 0.40), with a mean relative batch fecundity of 136 oocytes per gram of body weight. The relationships between batch and relative fecundity estimates and the associated biological metrics (length, body weight and ovary weight) were also investigated.

The EWG acknowledged the need for updated information on the reproductive and growth biology of albacore in the Mediterranean Sea, and encouraged the authors to present their findings to the next session of WGA.

The EWG followed a presentation on catches of albacore in the Ligurian Sea (STECF EWG 16-19 Doc. 8) There has never been a fishery targeting albacore, except for a short period in the early 60s, carried out during the summer months (July to September) and for only 6-7 years. There are no official estimates of those catches. After this period the resource was not available and fishing activities addressed to albacore were no longer present. All albacore catches nowadays are by-catch of gears targeting other species such as swordfish or Bluefin tuna.

A growth study was presented, carried out using all the available Ligurian Sea samples (n = 66), together with a good number of samples from the Ionian Sea (n = 228) for the smaller sizes. The parameters of the von Bertalanffy growth curve obtained are as follows: Linf = 95.71, k = 0.23 and t0 = -1.93. This curve is similar to those found in the literature for the same stock, even to those obtained using different methods (especially analysis of spines and scale). These results will be presented to the upcoming ICCAT stock assessment meeting in June 2017.

The EWG welcomed this additional study and considered that a more robust growth curve for the Mediterranean albacore stock could be obtained by integrating and comparing the various studies that have been carried out over the years. The possibility of a workshop involving scientists from all countries involved in data collection for this stock, to progress along these lines, should be considered and possible mechanisms for funding this activity could be explored.

Recovery of Italian data on albacore fisheries and biology

The EWG explored what other sources of information on catches, length samples in the catch, effort and biological sampling could be realistically be added to ICCAT datasets from the European fleets exploiting Mediterranean albacore. It appears that the greatest benefit would be obtained by an exercise directed at recovering data collected by the Italian authorities and not currently available to scientists nor present in ICCAT datasets.

A first step would entail making available to scientists the complete set of samples on biology on albacore that have been collected in 2010, 2013 and 2016 under the DCF. The samples taken inside the Italian national plan, later amended by the decisions of the MED planning group, should provide an important dataset on which to build a better understanding of the stock biology, and possibly of changes over time.

Some of the data collected under the DCR, has been presented to ICCAT scientific bodies during various meetings, both of the WGA and the SCRS. It appears some of those data submissions were incorporated in part into the ICCAT T2SZ datasets. But the precise knowledge on which data has been added, which one has not, and the reasons, is not clear to EWG. Contacts carried out with the ICCAT Secretariat indicated that a good deal of information that was put in their hands was not incorporated in the dataset due to problems with format, or the need for clarification on what data they should substitute.

The EWG considers that a complete analysis of the status of the Italian data for Mediterranean albacore tuna in the ICCAT datasets could be carried out by scientists with experience in this fishery and knowledge of the Italian data collection regime. This analysis would be followed by an evaluation of the expected quantity and, if possible, likely quality of the data collected by the Italian authorities the Multiannual Fishery Plans and DCR for the 2002-2009 period. Exploring the expected number of samples and methods used for data collection should be complemented by some evaluation of the status and location of these data. Although expected to be centrally stored, whether this files can be accessed and in what format will be found (most likely as paper copies) will have a clear impact on the feasibility of any recovery exercise. The information could also be expected to have remained at the various institutions tasked with collection, which might in some cases make recovery simpler or less arduous.

Finally, this fact-finding exercise should inform a decision on whether a full-blown data mining and recovery exercise should be carried out given the data likely to be unearthed and the importance of the data gaps that this information could fill compared with others.

REVIEW AVAILABLE INFORMATION FOR EVALUATING BY-CATCHES OF EUROPEAN ALBACORE FLEETS

The EWG attempted to provide a first enumeration of available data on the by-catch exercised by fleets targeting albacore tuna in the North Atlantic and Mediterranean. Many of these fleets have albacore as a primary target species for a period of the year and when operating in certain areas, so the denomination of by-catch for some other stocks might not be fully appropriate.

It should be noted that most of the information currently available originates from a number of studies financed totally or partly by DG MARE, and although some of them contain data that might not be reflective of the current situation, little information appears to be collected at the moment on this issue. It is likely that current and future changes in the management of these fisheries (e.g. the temporal closure for the protection of swordfish juveniles in the Mediterranean) will likely impact the behaviour of the fleets including their by-catch. The EWG noted that metiers ICCAT_11 and ICCAT_12 were not operating currently, so were not further considered.

The EWG noted that, according to this report, in the North Atlantic, some characterization of the bycatch of the principal commercial species was available for the main metiers involving midwater trawl, baitboat and trolling gears (metiers 1, 2 and 7 respectively). In the Mediterranean, this was also the case for metiers 4 and 6 (longline gear). Metier 13 (Sport fisheries both in the Atlantic and the Mediterranean) was the only one not having any characterization of the species and quantities of other commercially important species.

Beyond the comercially important species covered in the previous report, bycatch of other commercial or non-commercial species can be characterized using observer data. The group collected information on the availability of observer data for the main fleets targeting albacore in the Atlantic and Mediterranean (Table 3). In summary, in the Atlantic there is observer data, as well as some projects and studies, to characterize the bycatch of MWT. Regarding baitboats, there is only qualitative information (i.e. there are scientific observations of different trips but no specific design for studying bycatch, since the species they bycatch are target species that are landed, and these are studied with landing data, and reported to ICCAT). There is no scientific observation of Spanish troll trips. The bycatch of trollers seems also limited to target species, which is characterized through landings and submitted to ICCAT).

In the case of the Mediterranean, there is at least some observer information on longlines from Italy, Greece and Spain targeting albacore tuna. No studies are known for the Cyprus fleet.

North Atlantic

A presentation was made (STECF EWG-16-19 Doc. 11) summarizing the information available from the observer programme OBSMER ( 2016), that includes data on bycatch in the French fleets targeting albacore from 2006 to 2016.

The report revealed (Figure 14) that albacore is the main target species and it accounts 86% of catches and 89% of landings. The discarded fraction is fairly low (4.9% of the catch) and is composed of bluefin tuna (45%), albacore tuna (43%), and other species (12%). From the total catch, its represents 2.1% (= 64.1 tons) for albacore and 2.2% (= 66.8 tons) for bluefin tuna. Albacore is the main target species and it accounts 86% of catches and 89% of landings. Bluefin tuna is mostly discarded and represents only 9% of the landings and 11% of catches.

Mediterranean fleets

Results of the MEDPEL project, financed by DG MARE (SC No 6 (SI2.635542) MARE/2009/05-Lot 1), revealed that Greek and Italian longline fisheries targeting albacore are in general less selective that those targeting swordfish and bluefin tuna and, depending on the area and season, they may have relatively high by-catch of undersized swordfish and/or bluefin tuna individuals. Such by-catches are sometimes higher than the albacore catch itself in weight.

It should be noted that the available data from fisheries targeting albacore were temporarily fragmented and covered both Greek and Italian fleets exploiting different geographical sub-areas (GSA) of the Mediterranean. Table 3 presents the time and area coverage of the examined CPUE data.

Area Years

GSAs 20,22,23 2004-2006GSAs 19,21 1995-2003(except 1997) GSAs 10,11,12,15,16,19 1999and 2003-2008(except 2007) Table 4: Areas (GSA) and years for which the MEDPEL project has compiled information on bycatch from the Greek and Italian albacore fleets.

Regarding our current ability to estimate the by-catch levels of the European fleets targeting albacore tuna in the North Atlantic and Mediterranean, the EWG considers that the information exists that would allow an evaluation of what species are being caught, as well as a qualitative indication of the importance of this by-catch. A more precise evaluation of the catches being taken by species, or of the impact that retaining this catch on-board, as required under the Landing Obligation regulation, is only feasible for certain fleets and commercial species.

JRC Mission

As the science and knowledge service of the European Commission, the Joint Research Centre's mission is to support EU policies with independent, evidence throughout the whole policy cycle.

5

  Assessment of the quantity and quality of data as expected under current DCF requirements ................................................................................................................................... 6 Review the new catch and effort dataset of North Atlantic albacore caught by French mid-water trawl fleets ..................................................................................................................................................... New catch and effort dataset ..................................................................................................................... CPUE series ....................................................................................................................................................... 7 Assess availability and usefulness of data on catches of North Atlantic albacore by other fleets ........ 8 Discuss sources of information on changes in spatial distribution or fishing patterns ......................... 9 Identify sources of data on Mediterranean albacore of use for the next stock assessment ................... Biological data .................................................................................................................................................. Recovery of Italian data on albacore fisheries and biology ............................................................ 10 Review available information for evaluating by-catches of European albacore fleets ......................... North Atlantic ................................................................................................................................................... Mediterranean fleets ......................................................................................................................................

Figure 2 .

 2 Figure 2. Standardized CPUE series available for EU fleets, namely French troll (1975-1987),

Figure 1 :

 1 Figure1: SCRS catalogue on statistics(Task-I and Task-II) for north Atlantic albacore by major fishery (flag/gear combinations ranked by order of importance) and year(1995 to 2015). Only the most important fisheries (representing ±97.5%of Task-I total catch) are shown. For each data series, Task I (DSet= "t1", in tonnes) is visualised against its equivalent Task II availability (DSet= "t2") scheme. The Task-II colour scheme, has a concatenation of characters ("a"= T2 catch/effort exists; "b"= T2 size exists; "c"= Catch at size exists) that represents the Task-II data availability in the ICCAT database.

- 2015 -

 2015 Scientific bases to support management plans in the framework of the Common Fishery Policy (MIPAAF) -Operational Unit: UNIMAR. Title: Description of fishing activities of albacore (Thunnus alalunga) to identify reference parameters for the stock management -Study Characterization of large pelagic stocks (Thunnus thynnus L., Thunnus alalunga Bonn, Sarda sarda Bloch, Xiphias gladius L.) in the Mediterranean", funded by the EU.Includes data for the years 1992-1995, with many files collected that need to be worked out before being translated into ICCAT statistics.-MAREA Project -MEDPEL Catches of pelagic (drifting) longline fisheries in the Mediterranean (SC No 6 (SI2.635542)MARE/2009/05-Lot 1). Includes effort and size information for albacore targeting Italian longlines for the period 1995-2009 (with certain gaps).

Figure 5 :

 5 Figure 5: Nominal albacore CPUE (catches of albacore, Kg / vessel fishing time, hours) series for the French pelagic trawl fishery in the North Atlantic between 1991 and 2015.

Figure 6 :

 6 Figure 6: Standardized albacore CPUE (catches of albacore, kg / vessel fishing time hours) index for the 1991-2015 data period of the French mid-water trawl fishery, considering the catches on all regions combined. The black points represent the nominal CPUE, the solid red lines the standardized CPUE and the dotted red lines the 95% confidence intervals.

Figure 7 :

 7 Figure 7: Map of albacore CPUE represented in 1x1 degree grids. The boxes indicate the three main regions of operation of the fleets, used in the CPUE standardization.

Figure 8 :

 8 Figure 8: Effort distribution of the Portuguese pelagic longline fleet sampled in the North Atlantic used in this study, for the period 1999-2015. The effort is represented in number of hooks (x1000) in 5x5 degree grids.

Figure 10 :

 10 Figure 10: Nominal CPUE series (kg/1000 hooks) for albacore tuna captured by the Portuguese pelagic longline fishery in the North Atlantic targeting swordfish between 1999 and 2015. The error bars show the standard errors.

Figure Figure 9 :

 9 Figure Figure 9: Spatial distribution of the nominal CPUEs of albacore tuna in the North Atlantic captured by the Portuguese pelagic longline fleet, 1999-2015. The CPUE is represented in biomass (kg/1000 hooks) in 5x5 degree grids.

Figure 11

 11 Figure 11 Number of Spanish trolling (TR) boats with at least one positive albacore trip by year and region.

Figure 12 :

 12 Figure 12: Yearly spatial distribution of the trollilng fleet for years 2000-2002 and 2009-2011 derived from interviews to skippers (Ortiz de Zarate and Perez, 2016).

Figure 13 :

 13 Figure 13: Fit of the von Bertalanffy growth model to age and length (cm) readings of otholiths from the Ligurian and Ionian seas.

Figure 14 :

 14 Figure 14: Specific composition by weight of catches (top), landings (left) and discards (right) in 2015 observations for Pelagic trawl targeting the large pelagic species in Atlantic Ocean (modified from Obsmer report 2016).

  ISBN 978-92-79-67475-4 doi:10.2760/972246 LB-AX-17-003-EN-N STECF The Scientific, Technical and Economic Committee for Fisheries (STECF) has been established by the European Commission. The STECF is being consulted at regular intervals on matters pertaining to the conservation and management of living aquatic resources, including biological, economic, environmental, social and technical considerations.

TABLE OF CONTENTS

 OF SCIENTIFIC, TECHNICAL AND ECONOMIC COMMITTEE FOR FISHERIES (STECF) -European data for North Atlantic and Mediterranean albacore (STECF-17-03) ....... STECF response ................................................................................................................................................. STECF comments .............................................................................................................................................. STECF conclusions ............................................................................................................................................ Contact details of STECF members ............................................................................................................ Expert Group Report ...................................................................................................................................... 1 Executive Summary ...................................................................................................................... 2 Introduction...................................................................................................................................... 3 Terms of Reference to the Expert group ............................................................................... 4 Review the completeness and quality of European data for North Atlantic and Mediterranean albacore stocks .................................................................................................

North Atlantic albacore ................................................................................................................................. Mediterranean ..................................................................................................................................................

Table . Data availability for Thunnus alalunga, DCF -Italy.

 . Source: Italian Annual Reports on the activities performed under the National Data Collection Programs.

				Number of sampled individuals for:
		Landings by	Effort by month,
	Year	month and	by gear and by
		by gear*	GSA**	Length	Weigth	Age	Sex	Maturity
	2003	x		1093
	2004	x	x	728
	2005	x	x	1785
	2006	x	x	819
	2007	x	x	278	278
	2008	x	x	3079	3079
	2009	x	x	1077	1077
	2010	x	x	2486	2486	263
	2011	x	x	366	366
	2012	x	x	252	252
	2013	x	x	72	72	352	352	352
	2014	x	x	638	638
	2015	x	x	169

* Landings data are available by month, at fleet segment level and at métier level 6. Landings data refer to the métier and they are not species -specific. **The following effort variables are available for longliners by month and by GSA from 2004: Effort: Days, GTDays, KWDays, GTHours, Hours, KWHours, number of vessels, number of hooks. 2003 data available by fleet segment (prevalent fishing technique) and not by gear. Effort data refer to the métier and they are not species -specific.

EXPERT GROUP REPORT REPORT TO THE STECF Report of the Expert Group on European data for North Atlantic and Mediterranean albacore (EWG-16-19) Ispra, Italy, 13-16 March 2017

	Name Name Name Name	Address 1 Address 1 Address 1 Address 1				Tel. Tel. Tel. Tel.	Email Email Email Email
	STECF members STECF members STECF members STECF members
	Abella, Alvaro Andersen, Jesper Levring J. Sala, Antonello Italian National Research Independent consultant Department of Food and Resource Economics (IFRO) Section for Environment and Natural Resources University of Copenhagen Seefischerei -Palmaille 9, Council (CNR) Hamburg, Germany D-22767 Fischereiökonomie, AG und Fischerei, Institut für 63, 21000 Split, Croatia Döring, Ralf (vice-chair) Thünen Bundesforschungsinstitut, für Ländliche Räume, Wald Carmen Setaliste Ivana Mestrovica Evelina Salerno, Italy and Fisheries, Split, Sabatella, NISEA, Via Irno, 11, 84135 Vrgoc, Nedo Institute of Oceanography	Tel. 3384989821 Tel.dir.: +45 35 0039-2078841 Tel: +39 071 263 Fax.: 040 38905-33 68 92 185 089795775 21408002 Tel.: 040 38905-TEL.: +39 Tel.: +385	aabellafisheries@gmail.c om a.sala@ismar.cnr.it jla@ifro.ku.dk ralf.doering@thuenen.de e.sabatella@nisea.eu vrgoc@izor.hr
	Rolighedsvej 25 1958 Frederiksberg Denmark AZTI / Unidad de Investigación Herrera Gascuel, Didier AGROCAMPUS OUEST Arrizabalaga, Haritz Marina, 65 Route de Saint Brieuc, CS 84215, F-35042 RENNES Cedex France Institute of Marine Sciences (ISMAR), Largo Fiera della Pesca, 1 60125 Ancona -Italy Giuseppe Research Council (CNR), Scarcella, 1) Italian National	Tel.: +34667174477 Tel:+33(0)2.23.48 .55.34 Fax: +39 071 55313 Mob.: +39 Fax: 3283070446 +33(0)2.23.48.55. 2078846 35 Tel: +39 071	harri@azti.es Didier.Gascuel@agroca mpus-ouest.fr g.scarcella@ismar.cnr.it
	Bailey, Nicholas Knittweis, Leyla Lloret, Josep	kaia portualdea z/g 20110 Pasaia (Gipuzkoa), Spain Marine Scotland Science, Marine Laboratory, P.O Box 101 375 Victoria Road, Torry Aberdeen AB11 9DB Department of Biology University of Malta Msida, MSD 2080 Malta Associate Professor (Professor AGLANJIA, P.O.BOX 26728 Spain Ltd, 2, ACROPOLEOS ST. University of Girona (UdG), Environmental Consultancy Agregat), 2) AP Marine Institute of Marine Sciences (ISMAR) -Ancona -Italy Fiera della Pesca, 1, 60125 Fisheries Section, Largo	Tel: +44 (0)1224 876544 Direct: +44 (0)1224 295398 Fax: +44 (0)1224 Fax: +39 071 99664694 Tel.: +357 55313	baileyn@marlab.ac.uk n.bailey@marlab.ac.uk Leyla.knittweis@um.edu .mt josep.lloret@udg.edu gscarcella@apmarine.co m.cy
	Malvarosa, Bertignac, Loretta Soldo, Alen	NISEA S.c.a.r.l. 1647 Nicosia, Cyprus UK Laboratoire de Biologie Department of Marine	295511 tel : +33 (0)2 98 Tel.:	malvarosa@nisea.eu michel.bertignac@ifreme soldo@unist.hr
	Michel Martin, Paloma CSIC Instituto de Ciencias Halieutique Studies, University of Split,	22 45 25 -fax : Tel: 4.93.2309500 +385914433906	r.fr paloma@icm.csic.es
		del Mar Livanjska 5, 21000 Split, IFREMER Centre de Brest BP 70 -29280 Plouzane, Passeig Marítim, 37-49 Croatia	+33 (0)2 98 22 46 Fax: 53 34.93.2309555
	Somarakis,	France 08003 Barcelona Institute of	Marine	Tel.: +30 2810	somarak@hcmr. gr
	Borges, Lisa Stylianos Cardinale, Massimiliano Motova, Arina	FishFix, Brussels, Belgium Spain Biological Resources and Föreningsgatan 45, 330 Lysekil, Sweden Sea Fish Industry Authority 18 Logie Mill Logie Green Road Inland Waters (IMBRIW), Hellenic Centre of Marine Research (HCMR), Thalassocosmos Gournes,	337832 Tel: +46 18750 Tel.: +44 131 524 523 8662 Fax +30 6936566764	info@fishfix.eu massimiliano.cardinale@ slu.se arina.motova@seafish.c o.uk
	(vice-chair)	Edinburgh P.O. Box 2214, Heraklion
	Catchpole,	CEFAS EH7 4HS, U.K 71003, Crete, Greece Lowestoft		thomas.catchpole@cefas
	Thomas Murua, Hilario Stransky,	Laboratory, AZTI / Unidad de Thünen Institute [TI-SF]	Tel: Tel.	+49	0034 40	.co.uk hmurua@azti.es christoph.stransky@thue
	Christoph	Pakefield Road, Investigación Federal Research Institute Marina,	667174433 38905-228	nen.de
		Lowestoft Herrera for Rural Areas, Forestry	Fax: 94 6572555 Fax: +49 40
	Curtis, Hazel	Suffolk, UK NR33 0HT Sea Fish Industry Authority Germany (Gipuzkoa), Spain D-22767 Hamburg, Pasaia Sea Fisheries, Palmaille 9, kaia portualdea z/g 20110 and Fisheries, Institute of	Tel: +44 (0)131 38905-263	Hazel.curtis@seafish.co.
	Nord, Jenny (chair) Ulrich, Clara	18 Logie Mill Logie Green Road Edinburgh The Swedish Agency of Marine and Water Institute of Aquatic Management (SwAM) Denmark, National Technical University of	524 8664 Fax: +44 (0)131 558 1442 Tel. 0046 76 140 140 3	uk Jenny.nord@havochvatt en.se clu@aqua.dtu.dk
	Prellezo, Raúl	AZTI Resources, (DTU Aqua), -Unidad de EH7 4HS, U.K. Investigación Marina Charlottenlund Slot,	Tel: 667174368	+34	rprellezo@azti.es
	Daskalov, Georgi van Hoof, Luc	Laboratory Ecology, Institute of Biodiversity of Marine and Txatxarramendi Ugartea JaegersborgAllé 1, 2920 z/g Charlottenlund, Denmark 48395 Sukarrieta Ijmuiden, The Netherlands (Bizkaia), Spain IMARES, Haringkade 1,	Tel.: 646892 61061991 +359 Tel.:	52 +31	Georgi.daskalov@gmail. com Luc.vanhoof@wur.nl
	Raid, Tiit	Ecosystem Estonian Marine Institute, Research,	Tel.:	+372	Tiit.raid@gmail.com
	Vanhee, Willy	Bulgarian Academy of Sciences University of Mäealuse 14, Tallin, EE-Tartu, Independent consultant	58339340 Fax:	+372	wvanhee@telenet.be
		126, Estonia				6718900
	van	Fisheries	Economics,		Hans.vanOostenbrugge
	Oostenbrugge,	Wageningen	Economic		@wur.nl
	Hans	Research,	formerly	LEI
		Wageningen	UR,	The
		Hague, The Netherlands

16 4 REVIEW THE COMPLETENESS AND QUALITY OF EUROPEAN DATA FOR NORTH ATLANTIC AND MEDITERRANEAN ALBACORE STOCKS

  Review the current completeness and quality of the European data for the North Atlantic and Mediterranean albacore stock in ICCAT datasets, particularly focusing on data required for stock assessment and provision of advice.  Compare data quantity and quality with what could be expected to be submitted given the current data collection requirements for both stocks under the DCF.  Review the newly assembled dataset of catch and effort of North Atlantic albacore by the French mid-water trawl fleets, and assess its use as an index of abundance in the next stock assessment for the stock.  Assess the availability and information content of data on catches of North Atlantic albacore by fleets not targeting the species, such as European swordfish longliners, and evaluate their spatial and temporal coverage in comparison with those of existing CPUE series.  Discuss other sources of relevant information currently available which may help scientists to better interpret fisheries-dependent indices of abundance, particularly on the geographical distribution of the fishing activities and on possible historical changes in fishing patterns or fishing strategies in EU albacore fisheries of the North Atlantic and the Mediterranean Sea.  Identify European sources of data on Mediterranean albacore of interest to the upcoming stock assessment (catch, length sampling, indices of abundance), including those from fleets not targeting albacore, and propose strategies for the compilation, analyses and evaluation of those data sets prior to ICCAT's Albacore species group inter-sessional meeting (June 2017).  Review the available information and identify data gaps for the evaluation of by-catches in the European fleets targeting North Atlantic and Mediterranean albacore.

  that has size information for the Italian drift longline fleet fishing in the Adriatic(for 1990 and 2000), and SCRS document SCRS/2010/089[START_REF] Di Natale | Albacore (Thunnus alalunga) fisheries in the Tyrrhenian sea and in the South-central Mediterranean: fishery pattern, size frequencies, length-at-age[END_REF] that reports on the Italian albacore catches in the Tyrrhenian Sea(2003 to 2007) and in the Central-Southern Mediterranean (2004 to 2007) with information of catch, size, age and sex ratios. The WGA recommended a revision of Task 1 data by fleet and gear. Moreover, a cause of great concern is the high percentage of gear unclassified (UN) catches reported by Greece and Italy along the time series, which need to be revised and discriminated by fleet and gear. The WGA also detected some datasets with, for example, too large (>150cm) individuals reported (e.g. in 2003 for Italy, with an exceptional total catch reported, there is a high proportion of unclassified gear catch, some of it assigned to sizes that are beyond what is expected for this species).

Table 2 :

 2 Standardized CPUE models considered and fit diagnostics.

	AIC	R 2

  The Specific Contract for the provision of advice on the management of discards in EU fisheries beyond EU waters (Specific Contract No. 3 under Framework Contract No. MARE/2012/21) provides information on bycatch of other commercially important fisheries (i.e. bluefin tuna, bigeye tuna, yellowfin tuna and swordfish) for ICCAT metiers. The group used this information and filtered the metiers that catch albacore to characterize the available bycatch information from this source. The metiers that target albacore are:  ICCAT_01 Mid-water trawl fisheries for northern albacore taking place in Northeast Atlantic by French and Irish vessels.

	 ICCAT_12 Set gillnets fisheries, which are prohibited by ICCAT, for bluefin/albacore in the
	Mediterranean.
	 ICCAT_13 Recreational fisheries for albacore/bluefin in the Atlantic and Mediterranean by
	Cypriot, French, Greek, Italian, Maltese, Portuguese, and Spanish should they discard
	bluefin tuna.

 ICCAT_02 Hand and pole line (or bait boat) fisheries for northern albacore and eastern bluefin tuna taking place in ICCAT area Northeast Atlantic and Mediterranean by Cypriot, French, Greek, Italian, Maltese, Portuguese, and Spanish vessels.  ICCAT_04 Traditional small scale drifting pelagic and bottom longline targeting bluefin, albacore or swordfish taking place in the Mediterranean by Cypriot, Croatian, French, Greek, Italian, Maltese, Portuguese, and Spanish vessels.  ICCAT_06 Drifting pelagic longline targeting bluefin/albacore taking place in the East Atlantic by Portuguese and Spanish vessels, and drifting pelagic longline targeting bluefin/albacore taking place in the Mediterranean by Cypriot, French, Greek, Italian, Maltese, Portuguese, and Spanish vessels.  ICCAT_07 Trolling lines fisheries for albacore in ICCAT East Atlantic and Mediterranean Sea by Greek, Italian, Maltese, Portuguese, Spanish and United Kingdom vessels.  ICCAT_11 Trammel nets fisheries for albacore in the Mediterranean by Italian and Maltese vessels.

Table 3 :

 3 Summary of availability of bycatch information from observer data for each main fleet/gear targeting albacore.

	Region	Fleet/gear		Available information
	Atlantic	French MWT	-Obsmer dataset (France): 2006-2016
				-Morizur et al (1999): 1994
				-Morizur et al (1996) Study Bioeco-93-107 EC DGXIV C1: 1994
				(http://archimer.ifremer.fr/doc/1996/rapport-1236.pdf)
				-EU Study (Ifremer-IEO): 1989-1990.
		French		-EU Study (Ifremer-IEO): 1989-1990.
		Driftnets
		Irish MWT		-Pilot observer program EC 812/2004: 2011.
		Spanish		-EU Study (Ifremer-IEO): 1989-1990.
		baitboat		-Sparse survey and observer data with qualitative information on
				bycatch (AZTI): 2009, 2011, 2016
		Spanish troll	-EU Study (Ifremer-IEO): 1989-1990.
	Mediterranean Italian	ALB	-MEDPEL project: 1995-2009 with gaps.
		longline		-Italian Ministry program: 2015
		Italian Gillnet	-Identified during MEDPEL project (Univ. Bari): 1998-2006 with
				gaps.
		Greek	ALB	-MEDPEL project: 2004-2006
		longline
		Spanish	ALB	-Spanish observer program (IEO): 2006-2016 (except 2014)
		longline
		Cyprus	ALB	None known
		longline

Ortiz de Zárate and Perez (2016, SCRS/2015/025) showed the spatial distribution of the fleet through time (Figure12). However, in this database the trips are assigned to a single statistical rectangle where most of the activity of that trip took place, thus it is just an approximation to the real spatial distribution of the fishing activity. Alternative, daily logbook based information is available in Santiago (2004) andArrizabalaga et al (2010). However, this only represents the Basque fleet, a fraction of the Spanish fleet represented in the CPUE index. Moreover, the dataset is obtained through sampling, with varying number of boats per year providing logbook data.On the other indices (including the new French MWT index) the group noted that the general trends observed for the Spanish baitboat and the French MWT are similar, and coincide with the stock trend estimated in the assessment (partially influenced by the Spanish baitboat index), showing an increasing trend toward the end of the series. The Irish MWT index is very noisy, with no clear trend.The main issue between these indices is the sometimes opposite inter-annual variations between them, e.g. low CPUE for baitboat coinciding with large CPUE for IrishMWT (e.g. in 2008), which could just reflect different availability in their respective fishing areas, linked (or not) to environmental variability. The EWG could not detect any clear pattern on the inter-annual correlation between these and the newly developed French MWT index.

Committee for Fisheries (STECF) -European data for North Atlantic and Mediterranean albacore (STECF-Scientific, Technical and Economic Committee for Fisheries (STECF) -European data for North Atlantic and Mediterranean albacore (STECF-17-03)

This report was reviewed by the STECF during its in Ispra, Italy. Edited by Iago Mosqueira Report EUR 28359 EN This publication is a Science for Policy report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policy-making process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication.

CONTACT DETAILS OF EXPERT GROUP PARTICIPANTS

1 -Information on EWG participant's affiliations is displayed for information only. In any case, Members of the STECF, invited experts, and JRC experts shall act independently. In the context of the STECF work, the committee members and other experts do not represent the institutions/bodies they are affiliated to in their daily jobs. STECF members and experts also declare at each meeting of the STECF and of its Expert Working Groups any specific interest which might be considered prejudicial to their independence in relation to specific items on the agenda. These declarations are displayed on the public meeting's website if experts explicitly authorized the JRC to do so in accordance with EU legislation on the protection of personnel data. For more information: http://stecf.jrc.ec.europa.eu/adm-declarations

STECF members

Name

Address

Europe Direct is a service to help you find answers to your questions about the European Union.

Freephone number (*):

00 800 6 7 8 9 10 11 (*) The information given is free, as are most calls (though some operators, phone boxes or hotels may charge you).

More information on the European Union is available on the internet (http://europa.eu).

HOW TO OBTAIN EU PUBLICATIONS

Free publications:

• one copy:

via EU Bookshop (http://bookshop.europa.eu);

• more than one copy or posters/maps: from the European Union's representations (http://ec.europa.eu/represent_en.htm); from the delegations in non-EU countries (http://eeas.europa.eu/delegations/index_en.htm); by contacting the Europe Direct service (http://europa.eu/europedirect/index_en.htm) or calling 00 800 6 7 8 9 10 11 (freephone number from anywhere in the EU) (*).

(*) The information given is free, as are most calls (though some operators, phone boxes or hotels may charge you).

Priced publications:

• via EU Bookshop (http://bookshop.europa.eu).