Search

Based on the previous work from WKARHOM3 (ICES, 2018), the Working Group on Biological Parameters (ICES, 2020) identified the need for a new otolith exchange followed by an age read-ing Workshop. The Workshop on Age reading of Horse Mackerel, Mediterranean Horse Macke-rel and Blue Jack Mackerel (Trachurus trachurus, T. mediterraneus and T. picturatus) (WKAR-HOM4) had several main objectives; to review the current protocols of ageing Trachurus species, to update the advances in the validation of the ageing criteria (i.e. the annual deposition of one annulus, coherency of the interpretation), to evaluate the new precision of ageing data of Tra-churus species and to update guidelines, common ageing criteria and reference collections of otoliths. An online otolith exchange was performed using SmartDots during 2021 and 2022, and results including the three Trachurus species were published in advance of the meeting, showing a low Percentage of Agreement (PA) both when considering all the readers (44-55%) and the advanced readers only (52-54%) (Massaro and Jurado-Ruzafa, 2022). For T. trachurus the Coef-ficient of Variation (CV) was lower for the sliced samples (22-18%) than for whole otoliths sam-ples (44-38%). Readers participating in the exchange, following discussion during the WKAR-HOM4 meeting, agreed that the main cause of age determination error for T. trachurus was due to the different otolith preparation techniques (whole/sliced). These differences reflect the stunted growth and compactness of the annuli in older specimens (from the 4th-5th annuli on-wards). Anyway, for the three Trachurus species, there are several difficulties in age determina-tion: identification of the first growth annulus, presence of many false rings (mainly in the first and second annuli) and the interpretation and identification of the edge characteristics (opaque/translucent). The second reading exercise was performed during the workshop orga-nized in four different events (i.e. Trachuru

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters used in assessment and management. WGBIOP (1) plans workshops, exchanges, and validation studies on a range of biological varia-bles to review the quality of information supplied for stock assessment and improve quality as-surance and training; (2) investigates data availability and develops documentation and methods to improve communication between data collectors and end-users; (3) delivers new and im-proved functionality for the SmartDots platform. Four otolith exchanges and two workshops were completed in 2020–2021 using SmartDots— eight further exchanges are ongoing. Proposed future exchanges and workshops were reviewed and approved. The development of the SmartDots platform proceeded with the inclusion of the maturity, eggs, atresia, fecundity, and larval identification modules into the software version. A live SmartDots tutorial for event coordinators was conducted. Work to further develop quality assurance guidelines—and review national applications of these—progressed. Age and maturity validation studies were reviewed and a new method for prioritizing future validation work was proposed. Progress with the Stock Identification Database (SID) was reviewed, and the potential for creating a WGBIOP library collection and active involvement of WGBIOP in updating FishBase.org data were evaluated. The importance of identifying and documenting links be-tween all relevant databases and document repositories was identified, and a task to address this was initiated. Work on improving the feedback loop between data collectors and stock assessors on the usage and quality of biological parameters in stock assessment continued. Moving forward, WGBIOP aims to continue collaboration with WGALES and WGSMART on the development of the SmartDots platform, encouraging cross-group sharing of skills and ex-perience t

This study analyses the samples collected annually (2012 to 2018) on circalittoral and bathyal soft bottoms (30 to 800 m) by the MEDITS surveys in the northern Alboran Sea (including Alboran Island) and the Gulf of Vera to determine the composition, structure and distribution of decapod crustacean assemblages. A total of 94 decapod crustacean species were identified. Non-metric multidimensional scaling showed depth to be the main factor for distinguishing four main decapod assemblages: the inner shelf (30-100 m depth), outer shelf (101-200 m), upper slope (201-500 m) and middle slope (501-800 m). PERMANOVA analyses revealed further significant depth-related differences between three established geographical sectors of the study area (northern Alboran Sea, Gulf of Vera and Alboran Island). Generalized additive model analyses were used to assess the bathymetrical, geographical and environmental effects on the ecological indices of each assemblage. Results showed that depth and the geographical effect were the main drivers in all cases. Decreases in abundance and increases in species richness, Shannon-Wiener diversity and Pielou’s evenness indices with depth were detected. This study shows the primacy of depth and geographical effect on the distribution of decapod species in the study area, in alignment with findings from other parts of the Mediterranean Sea.

Independence of science and best available science are fundamental pillars of the UN-FAO code of conduct for responsible fisheries and are also applied to the European Union (EU) Common Fishery Policy (CFP), with the overarching objective being the sustainable exploitation of the fisheries resources. CFP is developed by DG MARE, the department of the European Commission responsible for EU policy on maritime affairs and fisheries, which has the Scientific, Technical and Economic Committee for Fisheries (STECF) as consultant body. In the Mediterranean and Black Sea, the General Fisheries Commission for the Mediterranean (FAO-GFCM), with its own Scientific Advisory Committee on Fisheries (GFCM-SAC), plays a critical role in fisheries governance, having the authority to adopt binding recommendations for fisheries conservation and management. During the last years, advice on the status of the main stocks in the Mediterranean and Black Sea has been provided both by GFCM-SAC and EU-STECF, often without a clear coordination and a lack of shared rules and practices. This has led in the past to: i) duplications of the advice on the status of the stocks thus adding confusion in the management process and, ii) a continuous managers’ interference in the scientific process by DG MARE officials hindering its transparency and independence. Thus, it is imperative that this stalemate is rapidly resolved and that the free role of science in Mediterranean fisheries assessment and management is urgently restored to assure the sustainable exploitation of Mediterranean marine resources in the future.

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters used in assessment and management. WGBIOP (1) plans workshops, exchanges, and validation studies on a range of biological variables to review the quality of information supplied for stock assessment and improve quality assurance and training; (2) investigates data availability and develops documentation and methods to improve communication between data collectors and end-users; (3) delivers new and improved functionality for the SmartDots platform. Four otolith exchanges and two workshops were completed in 2020–2021 using SmartDots—eight further exchanges are ongoing. Proposed future exchanges and workshops were reviewed and approved. The development of the SmartDots platform proceeded with the inclusion of the maturity, eggs, atresia, fecundity, and larval identification modules into the software version. A live SmartDots tutorial for event coordinators was conducted. Work to further develop quality assurance guidelines—and review national applications of these—progressed. Age and maturity validation studies were reviewed and a new method for prioritizing future validation work was proposed. Progress with the Stock Identification Database (SID) was reviewed, and the potential for creating a WGBIOP library collection and active involvement of WGBIOP in updating FishBase.org data were evaluated. The importance of identifying and documenting links between all relevant databases and document repositories was identified, and a task to address this was initiated. Work on improving the feedback loop between data collectors and stock assessors on the usage and quality of biological parameters in stock assessment continued. Moving forward, WGBIOP aims to continue collaboration with WGALES and WGSMART on the development of the SmartDots platform, encouraging cross-group sharing of sk

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters for use in assess-ments and management that are in line with the requirements of end-users. In this final year of the three-year term, WGBIOP operated under challenging circumstances due to COVID-19 measures. The initial action plan was replaced by a more flexible one, where online plenary and subgroup meetings were spread over the year with intersessional work to finalize the proposed deliverables. WGBIOP continued the review of past exchanges and workshops under the remit of the working group. Since 2019, these calibrations on age, maturity, and larvae identification have been carried out in SmartDots, an online platform for sharing images and facilitating the reading of otoliths, staging of gonads, and identification of early life stages. Developments are underway to include an improved calculation of modal age and error matrices in the SmartDots standard report. WGBIOP investigated ways to incorporate error matrices into assessments and studied the effect of this inclusion together with stock assessors. Requests for new exchanges and workshops were reviewed, with a focus on stocks to be bench-marked in the coming years. Issue lists were scrutinized, problems identified, and information provided to stock coordinators via regular channels and through the Stock Identification Data-base (SID). Despite close cooperation with stock assessors and continued efforts, it has not been possible to further streamline the WGBIOP workflow with the benchmark process. This will be addressed with the Advisory Committee. The need for validation studies was stressed by the repeated low levels of agreement between readers of some stocks and recurring issues and recommendations to WGBIOP. Lack of resources is the main obstacle. As a first step for measures to prioritize validation studies, WGBIOP iden-tified precision

Time series of European sardine (Sardina pilchardus) landings from 1962 and environmental variables from 1978 in the northern Alboran Sea are analysed. European sardine spawns in the northern Alboran Sea from mid-autumn to late winter at a temperature range slightly higher than the one observed in the nearby Eastern North Atlantic and the North Western Mediterranean. Individuals hatched during autumn and winter are incorporated to the fishery during the following summer and autumn producing the maximum annual landings. These landings show both a decreasing long-term trend and a strong inter-annual variability. Although further research is needed, the warming trend of sea surface temperature and the decrease in upwelling intensity inferred from empirical orthogonal function (EOF) analyses could have some influence on the negative trends of sardine landings. The inter-annual variability of sardine abundance seems to be related to the wind intensity at a local scale, the second principal component of the chlorophyll concentration and the sardine abundance during the preceding year. If the inter-annual variability is considered, a linear model including these three variables with a one-year time lag allows to explain 79% of the sardine landings variance. If the negative linear trend is also considered, the model explains 86% of the variance. These results indicate that the body condition of spawners, linked to the food availability during the preceding year, is the main factor controlling the recruitment success. The possibility of predicting sardine landings 1 year in advance could have important implications for fishery management.

Fish species play an important role in ecosystems, influencing the flow of energy and sustaining a diversity of ecosystem functions. In the Mediterranean sea, demersal resources consist of a large variety of fish species, many of them considered target species of economic interest for fisheries. Thus, understanding the distribution pattern of most relevant species is essential to improve spatial management and ensure a long-term sustainable conservation of the species. In this study, interannual and spatial distribution (bathymetric and geographic) of 9 relevant fish species (Serranus hepatus, Boops boops, Pagellus acarne, Capros aper, Merluccius merluccius, Coleorhinchus caelorhinchus, Phycis blennoides, Nezumia aequalis and Galeus melastomus) of the Alboran sea and the Gulf of Vera was evaluated. These species constitute some of the most representative in the soft bottoms of the study area from 30-800 m depth. In addition, fishing effort was analysed and compared with the standardized abundance for the above mentioned species

Based on the results of a full-scale otolith exchange held in 2014, the Working Group on Biological Parameters (WGBIOP 2015) identified the need for an age reading workshop on European Anchovy otoliths (WKARA2). This workshop (chaired by Andres Uriarte, Spain, Begoña Villamor, Spain and Gualtiero Basilone, Italy), was held in Pasaia, Gui-puzcoa (Spain) from the 28 November to 2 December 2016. Five countries took part in this workshop (Spain, Italy, Croatia, Greece and Tunisia), with a total of 16 participants from 9 laboratories. In total 17 areas/stocks were analysed (4 from the Atlantic area and 13 from Mediterranean Sea) The aim of this workshop was to review the information on age determination, discuss the results of the previous exchange (2014), review the validation methods existing on these species, clarify the interpretation of annual rings and update the age reading pro-tocol and a reference collection of well-defined otoliths. Age validation studies, in the Bay of Biscay and preliminary validation studies in Divi-sion 9a, Alboran Sea and Strait of Sicily areas were presented, including a compilation of age validation studies of this species as well in the literature. There are several ar-eas/stocks in which validations of the anchovy annual age determination have not been done yet. Due to the poor percentage of agreement achieved in the 2014 Exchange (mean agree-ment of 66%; mean CV of 58%), the workshop proceeded with a detailed and joint dis-cussion on the growth patterns shown by otoliths from the different areas to find out the major reasons for discrepancies in age determination among readers. At the same time, the joint discussion allowed a better understanding of the pattern of otolith growth in-crements by areas to improve the guidelines for their interpretation. The discussions on examples among otoliths which generated discrepancies in the age determination led to conclude that there were two major sources of disagreements: a) Divergent otolith

Small pelagic fish are among the most ecologically and economically important marine fish species and are characterized by large fluctuations all over the world. In the Mediterranean Sea, low catches and biomass of anchovies and sardines have been described in some areas during the last decade, resulting in important fisheries crises. Therefore, we studied anchovy and sardine body condition variability, a key index of population health and its response to environmental and anthropogenic changes. Wide temporal and spatial patterns were investigated by analyzing separately data from scientific surveys and fisheries in eight Mediterranean areas between 1975 and 2015. Results showed that anchovy and sardine body condition as well as maximum size in some areas sharply decreased in most Mediterranean areas along years (except in the Northern Alboran Sea). Despite this general pattern, well-marked environmental differences between sub-regions were highlighted by several analyses and variations in body condition were not found to be homogeneous over all the Mediterranean Sea. Further, other analyses revealed that except for the Adriatic where major changes towards a lower body condition were concomitant with a decrease in river runoffs and chl-a concentration, no concomitant environmental regime shift was detected in other areas. Together, these analyses highlighted the current poor body condition of almost all small pelagic fish populations in the Mediterranean. Yet, global environmental indices could not explain the observed changes and the general decrease in condition might more likely come from regional environmental and/or anthropogenic (fishing) effects. A prolonged state of poor fish body condition, together with an observed reduced size and early age-at-maturity may have strong ecological, economic and social consequences all around the Mediterranean Sea

The STECF expert working group "EWG 1419 - Mediterranean assessment part 2", has convened in Rome during 19-23 January 2015 and addressed a series of issues as requested by DG MARE in the correspomnding terms of references. The detailed output of this working group efforts is included in the following report. The report was reviewed by the STECF spring plenary during 13-17 April 2015

This study determines the seasonality in the formation of rings in the anchovy otoliths by monitoring hyaline edge in the Alborán Sea. Monthly samples were collected between October 1989 and December 1992 from the catches of the purse seine fleet. Two hyaline zones in the otolith are deposited per year, one in winter (primary) and a minor one during the summer spawning season. The formation of hyaline rings is significantly correlated with the temperature of seawater. The highest percentage of hyaline edge formation, recorded over the four year study, periodically occurred in February, when the temperature is at its lowest. When the nutritional status of fish is better, the percentage of individuals forming hyaline edge is lower. Considering these facts, a number of criteria for interpreting the growth rings on the anchovy otolith were developed. The population is subjected to a high rate of exploitation, so with the absence of older individuals in the area, it means that growth can only be accurately described in the first year. With some variations, depending on the year, anchovy grows between 12 and 13cm in their first year of life.

The MEDITS survey programme started in 1994 and adopted the basic protocols by the four first partners, just before the first survey. These protocols included the design of the survey, the sampling gear, the information collected, and the management of the data as far as the production of common standardized analyses of the data (Bertrand et al., 2002). The last updating of protocols has been done in 2007 (MEDITS, 2007). According to it, for each species the total weight and number of individuals is recorded. For a reference list of 38 species of fish, crustaceans and cephalopods, the length frequency by sex must be reported, as well as the maturity stage of the gonads. However, two different things should be taken into account. On one hand, for most works performed using MEDITS data (including assessments), the length frequency distributions are used, without taking into account the sex. On the other hand, the period of the surveys is not always coincident with the spawning season for all the species in the MEDITS reference list. This document attempts to be a practical exercise in relation to these topics, using both surveys and commercial data, and gives some proposals to the reference list of species

Recently it was stated a strong dependence of European hake abundance with climate variability in NW Africa. This relationship was explained by the North Atlantic Oscillation (NAO) driving the upwelling temporality and its geographic coverage, which could be responsible of changes in survival rate during early life stages of this species. Following this hypothesis, this work focuses on the relative importance of climate variability on recruitment dynamics of European hake. Interannual variability of recruitment success were analyzed through two types of time series: (i) from monthly and annual length distribution fishery data (1982-1999) of Spanish trawling fleet that worked under Spanish or European-Moroccan fishery agreements and (ii) recruits annual abundance from scientific Moroccan surveys (1982-2004). The time series were compared with the annual smoothed NAO index to evaluate the type of relationship, persistence and their relative contribution as a variation source of recruitment success. The recruitment to the fishery took place during all year with peaks in spring and summer, but the seasonal component was weak. The time series were in synchrony with NAO index of the previous year and showed strong positive correlation. The variation of recruitment success explained by NAO was 25 to 82 % depending on time series size. The main NAO effect in recruitment dynamics was the widening-contraction of Recruitment Window. During NAO+ phase several success cohorts were recruited by year, while in NAO- the success cohorts were scarce and weak. The climate signal in recruitment dynamics of European hake was robust, recurrent and persistent independently of fishing effort.

The MEDITS-99 sampling was performed along all the Iberian Peninsula coasts of the western Mediterranean (from the Alborán Sea to Cape Creus) in a space-scale of 1000 Km N-S, at depths ranging between 27-790 m. Fish and decapod crustaceans were dominant in the megafaunal compartment sampled by trawling. Based on both the fish and the decapod crustacean compositions, a comparison of trophic guilds has been attempted, with fish and decapods classified as: 1) migrator macroplankton feeders (mM), 2) non-migrator macroplankton feeders (nmM), 3) nektobenthos-suprabenthos feeders (NS), 4) epibenthos feeders (Epib), 5) large detritus-scavengers (Sca), 6) infaunal feeders (Inf), 7) deposit feeders (Dep) and 8) small detritivorous feeders (Det). Multivariate techniques showed the following differences in the trophodynamics of the megafaunal assemblages along the coasts of the Iberian Peninsula: 1) crustaceans (mainly decapods) have different trophic structures on the shelf and on the slope; 2) on the slope, fish exhibited more clear changes as a function of the geographical gradient than crustaceans; and 3) trophodynamics of bathyal fish showed some geographic variations between the Alborán Sea, the Catalano-Balearic Basin, and the Algerian Basin (Vera Gulf and Alicante sectors), with a progressive north-south increase in planktophagous species