The historical fisheries in the Mediterranean Sea: A reconstruction of trawl gear, effort and trends in demersal fish stocks

An extensive search of historical data sources and publications has been carried out in different countries of the Mediterranean. This lead to the construction of the largest compilation of historical fisheries information existing in the Mediterranean region. The goal first here was to quantify historical trawling effort. This shows that Mediterranean demersal communities underwent a much longer and more systematic exploitation than previously thought, very likely the longest known exploitation by means of trawls in Europe and North America. Analysis of the data available for the Catalonian, Italian and French areas showed a clearly emerging pattern: fishing capacity increased in Mediterranean EU countries up to and through the 20th Century until the 1980s-1990s, depending on the area. From that period on, fleet size has been decreasing steadily. However, it is unclear whether this decrease in vessel numbers in the last 20 years has been accompanied by a decrease in fishing power and fishing mortality. Trawl gear was reconstructed with the goal of deriving qualitative and quantitative estimates of increase in fishing power and improved gear performance. The rate of adoption of new technology (synthetic nets, hydraulic winches, navigation equipment, etc.) was reconstructed by area and the effect of these improvements on catch rates was discussed. Analysis of the change in the horizontal opening in trawl nets over time, parameter A1, proved that, with the adoption of new net material and net rigging, the actual size of the net, for the same vessel HP, almost doubled over 40 years. Reconstructing relative trends in demersal species abundance was one of the primary goals of this project and the intention was to go as far back in time as possible. A first set of analyses was carried out by individual fishing areas/countries with consistent data going back only to 1950. In Blanes, France, the Adriatic Sea and the Sicilian Channel, the drop in biomass was extremely large. In Tuscany the temporal trend since the mid 1960s appears flat but in this analysis the historical data are likely underestimates and a fishing power correction was not used. The second set of analyses pooled all available data together, including LPUEs from sail and steam trawlers from the beginning of the 20th Century and covered the entire western Mediterranean. When LPUE kg/fishing day was modeled, the highest relative biomass was identified in the 1920s with a second lower peak in the 1960s and contemporary biomass even lower. The further back the series was reconstructed, the larger the decline in demersal biomass. This is a quantification of the shifting baseline syndrome: today we are assessing stock solely based on data from the past 20 years, which correspond to the lower part of the trends in all models, so that we have no knowledge of the extent of the decline. A case study was built with data from Catalonia for individual species. Results showed steep declines for red shrimp and blue whiting and important declines for hake and mullets, although for the latter, residual patterns are not optimal. The overall depleted status of demersal stocks in most West Mediterranean calls for serious management and implementation of credible recovery plans for most demersal stock via adequate reductions of F paired with the establishment of large MPAs. The latter will allow the recovery of vulnerable species that have life history traits that would not be unresponsive compatible with even reduced fishing mortality levels. The incorporation of historical data will be of crucial importance for proper assessment of demersal stocks given the exploitation history as well as for the constructing rebuilding plans

The Mediterranean and Black Sea STECF Stock Assessment Database

Since 2007, the Scientific Technical Economic Committee for Fisheries (STECF), for which Joint Research Centre (JRC) runs the Secretariat and all the data collection process, started collecting and organizing information on Mediterranean and Black Sea fisheries, and since 2009 performing standardized stock assessments on these fisheries during STECF expert working groups (EWGs). The stock assessment results have been documented in more than 30 reports STECF EWGs (https://stecf.jrc.ec.europa.eu/reports/medbs). Stock assessments performed during the STECF EWGs employ different approaches and tools, however, models implemented in the Fisheries Libraries in R (FLR, http://www.flr-project.org) were the most used. After almost 10 years of stock assessments in the Mediterranean and Black Sea, JRC extracted available stock assessment data from digital repositories of EWGs and compiled a STECF reference database. From each assessment contained in the STECF reports yearly time series of stock variables such as:Total Catch (total weight of all fish in the stock), Recruitment (total number of individuals entering yearly in the population), Spawning Stock Biomass (total weight of all sexually mature fish in the stock) and Fishing Mortality were extracted. The assessments data are made available through an online interactive dashboard under the STECF Data dissemination web page (https://stecf.jrc.ec.europa.eu/dd/medbs/ram) that allow readers to compare and contrast several stock assessments variables. Each stock assessment is linked via an URL to the original source of the stock assessment. According to EU CFP - Common Fisheries Policy (Reg. EU 1380/2013 and Reg. EU812/2015) all EU commercial fish stocks should be fished at a maximum sustainable yield (Fmsy). Biological reference points, Fref (Fmsy or a proxy as F 0.1 ) and were subsequently used to assess if the level of exploitation (F/Fmsy) is in line with the CFP objectives (F/Fmsy≤1) or not (F/Fmsy >1). The STECF database is the reference database for the computation of the Common Fisheries Policy monitoring indicators for the Mediterranean and Black Sea (https://stecf.jrc.ec.europa.eu/documents/43805/2092142/STECF+18-01+adhoc+-+CFP+Monitoring+2018.pdf) To ensure traceability and foster reproducible scientific research, all the data, code and references part of the compilation process are hosted on GitHub, a well-known version control software platform. The target audience of the dashboard ranges from governments, fisheries institutes, stakeholders, NGO’s and common citizens that want to check the status of marine fisheries resources evaluated. A copy of the Mediterranean and Black Sea STECF stock assessment results will be included, for the first time, in the next release of the RAM legacy database: a voluntary contributed worldwide stock assessments database, RAM legacy, (http://ramlegacy.org/). The RAM Legacy database includes fish stock assessments from all around the world’s oceans, and provides a unique source of information to make comparisons between fisheries and to perform global analysis of stock status.JRC.D.2-Water and Marine Resource

DCF Data Call Coverage Report for the Mediterranean and Black Sea in 2014

DG Mare called the DCF Data from Member States in the Mediterranean and Black Sea on April 2014, defining the deadline of 9 June 2014 for data submissions from member states, under the Community Framework of Data Collection Regulation (DCR) (Council Regulation (EC) № 199/2008 of 25th February 2008). A second deadline specific for the Black Sea was established on 8 September 2014. The data call also defined a third deadline 12 January 2015 for the submission of trawl surveys data for Mediterranean MS. aruptii. The DCF data submitted by national correspondents are duly evaluated in the present coverage report by JRC DCF team as part of an Administrative Arrangement with DG MARE. The report provides a detailed review of the timeliness and completeness of data submissions by Member States.JRC.G.3-Maritime affair

Common Fisheries Policy Monitoring - Protocol for computing indicators

Common Fisheries Policy Monitoring - Protocol for computing indicators This document presents the protocol to compute indicators for monitoring the Common Fisheries Policy. A set of indicators both design-based and model-based are described mathematically. The list of stocks that should form the dataset on which the indicators are computed is also described as well as a set of rules to update the stocks' lists when needed. The protocol was presented and approved by the STECF's 2015 winter plenary (STECF-PLEN-15-03).JRC.G.3-Maritime affair

“Once upon a Time in the Mediterranean”. Long Term Trends of Mediterranean Fisheries Resources Based on Fishers’ Traditional Ecological Knowledge

We investigate long-term changes in the Mediterranean marine resources driving the trawl fisheries by analysing fishers’ perceptions (Traditional Ecological Knowledge, TEK) throughout the Mediterranean Sea for the last 80 years. To this end, we conducted an extended set of interviews with old experienced fishers that enabled us to classify species (or taxa) as 'decreasing' or 'increasing' both in terms of abundance, as well as average size in the catch. The aspect that most clearly emerged in all the investigated areas over time was the notable increase of fishing capacity indicators, such as engine power and fishing depth range. Atlantic mackerel, poor cod, scorpionfishes, striped seabream, and John Dory demonstrated a decreasing trend in the fishers' perceived abundance, while Mediterranean parrotfish, common pandora, cuttlefish, blue and red shrimp, and mullets gave indications of an increasing temporal trend. Although, as a rule, trawler captains did not report any cataclysmic changes (e.g. extinctions), when they were invited to estimate total overall catches, a clear decreasing pattern emerged; this being a notable finding taking into account the steep escalation of fishing efficiency during the past century. The overall deteriorating status of stocks in most Mediterranean regions calls for responsible management and design of rebuilding plans. This should include historical information accounting for past exploitation patterns that could help defining a baseline of fish abundance prior to heavy industrial fisheries exploitation.JRC.G.3-Maritime affair

The a4a Assessment Model - Model description and testing

The a4a initiative aims to provide timely and cost effective advice for the circa. 250 fish stocks that, through the EU Data Collection Framework, will have at least 10 years of data by the year 2020. Current processes for assessing the state of and managing fish stocks are intensive processes, each stock requiring the attention of one or more stock assessment scientist to produce preliminary catch advice, which is subsequently reviewed by one or two committees before the final catch advice is published. Ingrained in the development of these processes has been the development of more and more complex stock assessment models which typically require highly skilled personnel to set up and run.JRC.G.4-Maritime affair

Model based CFP indicators, F/Fmsy and SSB Mediterranean region case study

This work presents the application to Mediterranean stocks of a set of model-based indicators, being developed for monitoring the implementation of the Common Fisheries Policy (CFP). The work constitutes an application of the methodology, as such the results should not be used as representative of the CFP implementation in the Mediterranean. This document is mainly constituted of R code, showing how the indicators can be computed and presenting a set of diagnostics and stability tests. The models tested were a linear model, a linear mixed effects model with random intercept by stock, a GAMM with random intercept by stock and a GAMM with random intercept by Mediterranean GSA and species. The stability tests were designed to evaluate the estimates of recent (2003-2013) time series of trends in SSB and annual mean values of F/Fmsy. The results were presented to the STECF's 2015 winter plenary (STECF-PLEN-15-03).JRC.G.3-Maritime affair

Testing the robustness of HCRs applied to Baltic pelagic stocks - Working Document in support to the STECF Expert Working Group 12-02 Management Plans - part 1

This work replies to a request from STECF EWG 11 15 to JRC to provide tests on the robustness of the target shing mortality (Ftrgt) and biomass trigger (Btrg) used on the harvest control rule (HCR) of the Baltic pelagic stocks. The main conclusion is that the successful candidates must assure Btrg is above the S/R break point and an exploitation level that is consistent with Btrg considering the stock dynamics.JRC.G.4-Maritime affair

a4a short research project: Stock assessment of Hellenic Small Pelagic Stocks

With the objective of applying the a4a methods to real life situations the JRC held a Workshop on stock assessment for the Hellenic small pelagic stocks in the Aegean Sea (JRC, Italy) between the 4th and 7th of May 2015. The main objectives were to compare assessment models and incorporate environmental indices into stock forecasts.JRC.G.3-Maritime affair

a4a assessment model simulation testing

The a4a initiative seeks to overcome these issues by developing a flexible, robust and easy to use stock assessment model, thus making stock assessment accessible to a wide range of scientists that do not have the high skilled quantitative background required to run very complex models. Forthcoming research will describe how to overcome the burden of producing catch advice for such a large number of stocks. This technical report presents assessment model simulation testing undertaken under the a4a Initiative.JRC.G.4-Maritime affair