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The opaque nature of illegal, unreported, and unregulated (IUU) fishing means that the data on catches are scarce or unreliable, making it difficult to estimate the volume of illegal fishing and the number of individuals who practice it. In this work, we develop the use of quantification methods for IUU fishing in data-poor fisheries and provide estimates for the main shellfish species exploited in S-fisheries in Galicia (NW Spain). To make the estimates, we use a model whose primary input is the Confiscations per unit of policing effort (CPUPE) index, which relates the sanctions imposed for poaching, estimated poaching, and confiscations carried out by the Enforcement Forces. The estimates for the period 2012–2020 are 660.2 t of illegal catches of different species and an average number of 1,766.2 poachers/year. These estimates provide evidence that makes it possible to analyse tendencies in illegal fishing, to establish assessment baselines and to highlight potential improvements in the fight against IUU fishing in small-scale fisheries

Over the past two decades, enormous progresses have been made in high-throughput sequencing (HTS) method development. This fact unveiled the potential usefulness of HTS methods in a wide range of fields such as fishery assessment and management, for which their application has been extensively discussed. As a consequence of the rapid development, sequencing costs have continuously declined, leading to a general claim that HTS methods are cost-efficient compared with traditional ones. Within this context, the underlying research objective is to assess the cost-effectiveness of genomic techniques through a review of the state of the art (SoA) on three HTS methods: i) environmental DNA (eDNA); ii) epigenetics method for age determination through DNA methylation (DNAm), and; iii) close-kin mark-recapture (CKMR) applied on marine ecosystems and fisheries and for stock assessment purposes. The SoA review of the literature on HTS methods was performed through the snow-balling systematic reviewing approach. The analysis has considered the set of processes and variables necessary to perform the stock assessment and compared the capacity of current and HTS methods for providing the required data. Research reveals that HTS methods constitute a promising tool for fishery research and, particularly, for improving scientific advice. Nevertheless, up to now, only one research, on a non-commercial species, has been conducted on the application of HTS methods for stock assessment purposes. Although some partial data are present in the literature, no systematic analysis on costs has been found. This paper suggests that the future research agenda should attempt to straddle both the scenarios for the transition process, considering complementary implementation and substitution possibilities and their cost-efficiency. Clarifying these questions is likely to pave the way for the effective and step-wise implementation of these methods in fishery management; thus, further research is recom

The cost-efficiency analysis of genetic HTS methodologies is aimed for understanding the potential of these methodologies for reducing the financial burden of aquatic and marine life assessments without increasing the uncertainty of the biological parameters relevant for such assessments which can be obtained through these methods. Even though several pieces of research have claimed that these methodologies are cost-efficient, most of them refer to uses different to the stock assessment of commercial fish species. The cost-efficiency analysis estimates the ratio of ‘program’ costs to outputs created, allowing to compare cost-per-output for programs producing equivalent outputs. In our case, outputs are the necessary data for performing an accurate stock assessment. The cost-efficiency analysis of the HTS methods compared to the currently used ones in the research surveys requires identifying the cost components in each case, to measure the relative efficiency and to understand the origin of the differences. Fisheries research surveys are not performed in a single way, they differ significantly one to another. A variety of stock assessment evaluation methods are regularly used. They also differ on the requirements on a priori information about the stock, in biological data and fishing parameters, in the time range of this data needed to run it with confidence, etc. A survey design conditions the efficiency of the surveys and the eventual optimization of the cost components. This study presents a contextualised approach for the cost comparison needed and identifies some potential pathways for efficiency both on the surveys at sea and on the lab, where the sampling processing takes place until the output data is made available for the stocks assessment.

Global marine fisheries are underperforming economically because of overfishing, pollution and habitat degradation. This fact has serious implications over marine habitats such as latitudinal and in-deep migrations and modifications of the stock – recruitment relationship. It generates a reduction in the number of individuals on fisheries and, subsequently, an increasing number of overexploited stocks. Nowadays the majority (85 percent) of Mediterranean and Black Sea stocks for which a validated stock assessment exists are fished outside biologically sustainable limits (GFCM, 2016). It is necessary to mitigate the negative impacts over marine fish stocks and improve the state of fish stocks reverting the negative ecological, economic and sociologic effects. Decreasing recruitment trend has also serious negative implications on stock dynamics and, subsequently, affects the accuracy of stock estimates. Stock estimates are the basis for fisheries managers to determine quotas and management regulations. On one side, the aim of the investigation is to replicate using Assessment for All (a4a) stock assessment tool the last 2016 Working Group on Demersal Species (WGSAD) Extended Survival Analysis (XSA) validated stock assessment for European hake in the Strait of Sicily (GSA’s 12-16). Main benefit of using a4a is the capability to introduce an uncertainty parameter in the stock assessment process. It allows to describe better the stock dynamics and, thus, increase the quality of the scientific advice. Also, an assessment of management scenarios was carried on finding possible alternatives in the management of the resource in the Strait of Sicily fishery. Those management scenarios were compared to identify dissimilarities related with the use of different models to assess the stock. On the other side the aim of the investigation is to investigate the implications of decreasing recruitment trends or consider constant recruitment values along the timeseries assessing the con