Compilation and quality check of the ICES stock assessment data

For the analysis of the CFP indicators for NE Atlantic stocks, stock assessment data had to be obtained from ICES. These data included time-series of stock size, fishing pressure and reference points for each stock. This document describes the compilation process of this dataset, including the data quality checks and corrections that were carried out.Embedded R code is executed to generate the polished ICES dataset used in the analysis for the CFP indicators report.JRC.D.2-Water and Marine Resource

Sampling Frame for Mediterranean and Black Sea CFP Monitoring indicators

The Mediterranean and Black Sea list of stocks to be used for computing the indicators was based on a ranking system approach for which the species having a rank in the first ten positions either in total live weight or total economic values were chosen. Landings and economic values for the Mediterranean and Black Sea (FAO area 37) provided by “2016_STECF 16-11 - EU Fleet Economic and Transversal data tables” were used. The reference years were 2012 and 2014 (the last three years available for all the GSAs) and, as geographic strata, the Geographical Sub Areas (GSAs) belonging to EU countries and for which data were available were considered. In the top ranking 10 stocks based on both in terms of live weight and economic value by GSA applied to AER Landings, many combined/nei groups categories were selected. Based on local expert knowledge it was possible split some mixed categories at species level while, it was decided to drop from the list both the misreporting species and the mixed categories for which it wasn't possible defined clearly the species composition. Eventually 230 stocks were selected.JRC.D.2-Water and Marine Resource

Operationalizing ensemble models for scientific advice to fisheries management

This paper explores the possibility of using the ensemble modelling paradigm to fully capture assessment uncertainty and improve the robustness of advice provision. We identify and discuss advantages and challenges of ensemble modelling approaches in the context of scientific advice. There are uncertainties associated with every phase in the stock assessment process: data collection, assessment model choice, model assumptions, interpretation of risk, up to the implementation of management advice. Additionally, the dynamics of fish populations are complex, and our incomplete understanding of those dynamics and limited observations of important mechanisms, necessitate that models are simpler than nature. The aim is for the model to capture enough of the dynamics to accurately estimate trends and abundance, and provide the basis for robust advice about sustainable harvests. The status quo approach to assessment modelling has been to identify the “best” model and generate advice from that model, mostly ignoring advice from other model configurations regardless of how closely they performed relative to the chosen model. We discuss and make suggestions about the utility of ensemble models, including revisions to the formal process of providing advice to management bodies, and recommend further research to evaluate potential gains in modelling and advice performance.publishedVersio

Assessment for All initiative(a4a) - Workshop on development of MSE algorithms with R/FLR/a4a

The a4a approach to Management Strategies Evaluation ( MSE ) is to develop a set of common methods and procedures to build a minimal standard MSE algorithm. This has the most common elements of both uncertainty and management options. Such a tool set should allow for the development of MSE simulations for many fisheries in an operational time frame. Between the 30th of January and the 3rd of February, in Ispra, Italy, the JRC organized a workshop on development of MSE algorithms with R/FLR/a4a. The workshop was a mix of hands-on coding and discussion/implementation of concepts associated with MSEs. The participants used the most recent version of the a4a MSE code, modularized the most important processes and developed their own version of several processes so that the MSE could model and test alternative management procedures to the one initially coded.JRC.D.2-Water and Marine Resource

Are we ready to track climate-driven shifts in marine species across international boundaries? - A global survey of scientific bottom trawl data

Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio-temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate-driven ocean changes.En prensa6,86

Coherent Assessments of Europe’s Marine Fishes Show Regional Divergence and Megafauna Loss

Europe has a long tradition of exploiting marine fishes and is promoting marine economic activity through its Blue Growth strategy. This increase in anthropogenic pressure, along with climate change, threatens the biodiversity of fishes and food security. Here, we examine the conservation status of 1,020 species of European marine fishes and identify factors that contribute to their extinction risk. Large fish species (greater than 1.5 m total length) are most at risk; half of these are threatened with extinction, predominantly sharks, rays and sturgeons. This analysis was based on the latest International Union for Conservation of Nature (IUCN) European regional Red List of marine fishes, which was coherent with assessments of the status of fish stocks carried out independently by fisheries management agencies: no species classified by IUCN as threatened were considered sustainable by these agencies. A remarkable geographic divergence in stock status was also evident: in northern Europe, most stocks were not overfished, whereas in the Mediterranean Sea, almost all stocks were overfished. As Europe proceeds with its sustainable Blue Growth agenda, two main issues stand out as needing priority actions in relation to its marine fishes: the conservation of marine fish megafauna and the sustainability of Mediterranean fish stocks

Participatory management in a high value small-scale fishery in the Mediterranean Sea

In the Mediterranean Sea, the dominant type of fisheries is small-scale. Coastal communities remain dependent on fisheries for their income, some of them with limited potential for economic diversification. The top-down micro-management regime has proven ineffective to secure ecological and social sustainability as it lacks flexibility and adaptation to local and regional conditions. This paper explores the advantages of using a participatory approach and a bio-economic model to develop management scenarios in a high value small-scale shrimp trap fishery in Greece. Seeking active stakeholder involvement throughout the management process advanced the identification of management measures aiming at MSY, with high levels of acceptance from stakeholders. It also increased transparency and legitimacy of the proposed management measures and could be considered as a first step towards co-management and regionalization. The participatory approach undertaken could promote compliance and facilitate the transition to sustainable fishing, ensuring the viability of coastal communities and, thus, social sustainability.JRC.D.2-Water and Marine Resource

Bat species richness and activity over an elevation gradient in mediterranean shrublands of Crete

<strong>Abstract</strong><br /> The effect of elevation on bat species richness and activity was investigated in shrublands of central Crete (Greece) using broad-band acoustic surveys. Recordings of echolocation calls were made in 15 transects equally distributed in three distinct elevation zones (500, 1000 and 1500 m a.s.l.) during spring and autumn 2007-2008. Time-expanded calls were subsequently identified with the use of quadratic discriminant functions.<br /> Out of 13 species recorded, <em>Hypsugo savii</em>, <em>Pipistrellus kuhlii</em> and <em>Tadarida teniotis</em> were the most common and abundant. Many <em>Rhinolophus hipposideros</em> were also recorded in all elevation zones. Thirteen species were recorded in the lower elevation zone, 7 species in the mid one and 8 species in the 1500 m a.s.l. sites. Species richness, the number of bat passes of the most abundant species, as well as the total number of bat passes were not significantly affected by elevation. In spring both species richness and bat activity were higher than in autumn, although the corresponding difference in temperature was not significant.<br /> The high variability in both bat activity and the number of species found per transect in each elevation zone probably depended on the presence of other habitat types in the close vicinity, while roost availability and location might also have played an important role.<br /> We suggest that the ability of bats to perform regular movements along the elevational gradient has to be taken in account when assessing elevational patterns in bat diversity and activity. The geology of the study area is also of considerable importance through its effect on foraging and roosting opportunities for bats.<br /> <br /> <strong>Riassunto</strong><br /> <strong>Ricchezza specifica e attività dei chirotteri lungo un gradiente altitudinale nella macchia mediterranea di Creta</strong><br /> L’effetto della quota su ricchezza in specie e attività dei chirotteri è stato investigato in siti di macchia mediterranea mediante rilevatori ultrasonori nella regione centrale dell’isola di Creta (Grecia). In primavera ed autunno 2007 e 2008, abbiamo registrato i segnali di ecolocalizzazione lungo 15 transetti egualmente distribuiti in tre fasce altitudinali (500, 1000 e 1500 m s.l.m.). I segnali registrati in “time expansion” sono stati successivamente identificati mediante funzioni discriminanti quadratiche.<br /> Delle 13 specie registrate, <em>Hypsugo savii</em>, <em>Pipistrellus kuhlii</em> e <em>Tadarida teniotis</em> sono risultate le più comuni e abbondanti. Nella fascia altitudinale più bassa abbiamo registrato 13 specie, 7 in quella intermedia e 8 nei siti a 1500 m s.l.m. La ricchezza specifica, il numero di passaggi delle specie più frequenti, così come il numero totale di passaggi non sono risultati significativamente influenzati dalla quota. In primavera, sia la ricchezza specifica sia l’attività sono risultate maggiori che in autunno, sebbene le corrispondenti differenze di temperatura non fossero significative.<br /> L’elevata variabilità nell’attività dei chirotteri e nel numero di specie tra siti entro ciascuna fascia altitudinale si spiega probabilmente con la presenza di altri tipi di habitat nelle immediate circostanze dei siti investigati; anche la presenza e la localizzazione di rifugi può avere una influenza su tale variazione. Suggeriamo che la capacità dei chirotteri di spostarsi regolarmente lungo il gradiente altitudinale debba essere considerata negli studi che analizzano l’influenza della quota sulla diversità e abbondanza della chirotterofauna. Anche la natura geologica dell’area di studio, influendo sulla disponibilità di siti di alimentazione e rifugio, può svolgere un ruolo determinante.<br /> <br /> <tt>doi:10.4404/hystrix-21.1-4485</tt&gt

That’s all I know: Inferring the status of extremely data-limited stocks

There is a growing number of methods to assess data-limited stocks. However, most of these methods require at least some basic data, such as commercial catches and life history information. Meanwhile, there are many commercial stocks with an even higher level of data limitation, for which the inference of stock status and the formulation of advice remain challenging. Here, we present a stepwise approach to achieve the best possible understanding of extremely data-limited stocks and facilitate their management. As a case study we use a stock of the shrimp Plesionika edwardsii (Decapoda, Pandalidae) from the eastern Mediterranean Sea, where the only available data was a sub optimal sample of length frequencies coming from a small-scale trap fishery. We use a suite of different methods to explore and process the data, estimate the growth parameters, estimate the natural and fishing mortalities, and approximate the reference points, in order to provide a preliminary evaluation of stock status. We implement multiple methods for each step of this process, highlighting the strong and weak points of each one of them. Our approach illustrates the better insights that can be gained by applying ensembles of models, rather than a single ‘best’ model when working with limited data of poor quality. The stepwise approach we propose here is transferable to other extremely data-limited stocks to elucidate their status and inform their management.JRC.D.2-Water and Marine Resource