Assessing the State of Demersal Fish to Address Formal Ecosystem Based Management Needs: Making Fisheries Independent Trawl Survey Data ‘Fit for Purpose’

In Europe, introduction of the Marine Strategy Framework Directive (MSFD) represents formal, legally-binding, adoption of ecosystem-based management (EBM) across most European waters. Member States of the European Union have invariably nominated their groundfish surveys as part of the marine monitoring programs required under the MSFD. Groundfish surveys were originally intended to provide fisheries independent abundance indices for commercially valuable species to support fisheries stock assessments and fisheries management. However, early studies, primarily intended to make the case for the need for EBM, exposed these data to a broader range of uses and highlighted various data quality issues. Individual scientists, pursuing personal research agendas, addressed these as each thought best. This informal approach to assuring data quality is not sufficient to support formal assessments of fish species status and fish community status required under legally-mandated EBM, such as the MSFD, because quality audit, formal logging of issues identified, and remedial measures taken, is often lacking. Groundfish survey data, needed to implement legally-mandated EBM, should be subjected to a formal Quality Assurance–Quality Audit (QAQA) process to ensure that they are properly fit for purpose. This paper describes a QAQA process applied European groundfish survey data to ensure their adequacy to support MSFD needs and considers how this process might be taken forward in the future

Exploring the influence of food and temperature on North Sea sandeels using a new dynamic energy budget model

The zooplanktivorous schooling fish sandeels A. marinus comprise a quarter of North Sea fish biomass and are essential food for a number of marine mammals and birds. However, in recent decades there has been a decline in the abundance of older sandeels, with increased overwinter mortality proposed as a contributor. To survive winter animals require a minimum energy reserve which is determined by temperature, prey abundance, and possibly prey size. Here a new dynamic energy budget model is created to determine the influence of food and temperature on sandeel energy dynamics. The model hindcasts changes in energy and survival between 2000 and 2008, a period of pronounced stock decline in the northwestern North Sea. Overwinter starvation mortality was a large contributor towards a recent decline in sandeels in northern UK waters. Highest over-winter mortality rates were recorded for juveniles and not individuals aged 1 or over due to the effect of weight-specific metabolism. However, a sensitivity analysis of the model suggests that mortality rates are more sensitive to changes in copepod abundance in the build up to overwintering rather than temperature during overwintering. Further, projections show that temperature rises are negated by increases in large, but not small copepods. The conclusion is that food-driven size-selective starvation mortality contributed to the northwestern North Sea stock decline and that indirect food web effects of climate change are greater than direct physiological effects on sandeels

Timing of sandeel spawning and hatching off the East Coast of Scotland

The lesser sandeel, Ammodytes marinus, is a key forage fish species in the North Sea. Mean lengths and abundances of sandeels have declined steeply since the 1990’s and these are associated with declining breeding success of various seabird species on the east coast of Scotland, especially kittiwakes. The declining lengths have led to a mismatch between the peak in food demand arising from chick rearing, and the appearance of appropriately sized young sandeels in the foraging areas of the birds. A 10-year time series of sandeel larval samples between 2000 and 2009 offer a rare opportunity to analyze trends in spawning and hatch dates and determine whether they contributed to changes in mean lengths. By analyzing the abundance, length, and age distributions of sandeel larvae we were able to determine the temporal distribution of hatching rates each year, and back-track to the likely spawning dates of the sandeels. Estimated spawning dates showed no evidence of correlation with environmental cues such as tidal or lunar phases. However, hatch end dates varied by 20 days over the 10-year period and were correlated with the date of the seasonal minimum of sea bottom temperature. We show a significant decline between growth rate and 0-group length between 2000 and 2009, and suggest that changes in food quality and availability, rather than shifts in hatch dates, are likely to be responsible for current declines in the availability of sandeels to seabirds

Trends in Sandeel Growth and Abundance off the East Coast of Scotland

Sandeels Ammodytes marinus are a crucial forage fish species in the North Sea, transferring zooplankton energy to higher trophic levels. However, there has been a sustained decline in sandeel abundance in the northwestern North Sea since 2000. Here we use field data to analyse year-to-year changes in A. marinus growth rate between 1997 and 2009 and assess whether variation in growth rate corresponded with variation in abundance. The signature of the reduction in abundance between 2000 and 2009 was a decline in age 1 sandeels, while no other age class declined. Analysis of age-length data showed that the decline in abundance coincided with a period of low growth. Growth performance indexes were correlated with zooplankton and phytoplankton biomass but not temperature. Further, we observed a significant correlation between larval growth rate and 0-group sandeel length during a period when hatch dates were relatively fixed; suggesting recent changes in length were influenced by food availability

Surveillance indicators and their use in implementation of the Marine Strategy Framework Directive

Abstract The European Union Marine Strategy Framework Directive (MSFD) uses indicators to track ecosystem state in relation to Good Environmental Status (GES). These indicators were initially expected to be “operational”, i.e. to have well-understood relationships between state and specified anthropogenic pressure(s), and to have defined targets. Recent discussion on MSFD implementation has highlighted an additional class of “surveillance” indicators. Surveillance indicators monitor key aspects of the ecosystem for which there is: first, insufficient evidence to define targets and support formal state assessment; and/or second, where links to anthropogenic pressures are either weak or not sufficiently well understood to underpin specific management advice. Surveillance indicators are not only expected to directly track state in relation to GES, but also to provide complementary information (including warning signals) that presents a broader and more holistic picture of state, and inform and support science, policy, and management. In this study, we (i) present a framework for including surveillance indicators into the Activity–Pressure–State–Response process, (ii) consider a range of possible indicators that could perform this surveillance role, and (iii) suggest criteria for assessing the performance of candidate surveillance indicators, which might guide selection of the most effective indicators to perform this function.</jats:p

Bridging the gap between policy and science in assessing the health status of marine ecosystems

Human activities, both established and emerging, increasingly affect the provision of marine ecosystem services that deliver societal and economic benefits. Monitoring the status of marine ecosystems and determining how human activities change their capacity to sustain benefits for society requires an evidence-based Integrated Ecosystem Assessment approach that incorporates knowledge of ecosystem functioning and services). Although, there are diverse methods to assess the status of individual ecosystem components, none assesses the health of marine ecosystems holistically, integrating information from multiple ecosystem components. Similarly, while acknowledging the availability of several methods to measure single pressures and assess their impacts, evaluation of cumulative effects of multiple pressures remains scarce. Therefore, an integrative assessment requires us to first understand the response of marine ecosystems to human activities and their pressures and then develop innovative, cost-effective monitoring tools that enable collection of data to assess the health status of large marine areas. Conceptually, combining this knowledge of effective monitoring methods with cost-benefit analyses will help identify appropriate management measures to improve environmental status economically and efficiently. The European project DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status) specifically addressed t hese topics in order to support policy makers and managers in implementing the European Marine Strategy Framework Directive. Here, we synthesize our main innovative findings, placing these within the context of recent wider research, and identifying gaps and the major future challenges

Report of the JRC’s Descriptor 1 workshop to support the review of the Commission Decision 2010/477/EU concerning MSFD criteria for assessing Good Environmental Status

The MSFD workshop on biodiversity (MSFD D1), held in Ispra JRC (7th-9th of September 2015) aimed to provide clear proposals and conclusions on some of the outstanding issues identified in the D1 review manual (May 2015 consultation version: https://circabc.europa.eu/w/browse/46d2b7ba-d2fd-4b3c-9eaf-18c7cb702b53) in the broader context of support to the review of Commission Decision 2010/477/EU. This report is complementing the Commission Decision 2010/477/EU review manual (JRC96521) and presents the result of the scientific and technical review concluding phase 1 of the review of the Commission Decision 2010/477/EU in relation to Descriptor 1. The review has been carried out by the EC JRC together with experts nominated by EU Member States, and has considered contributions from the GES Working Group in accordance with the roadmap set out in the MSFD implementation strategy (agreed on at the 11th CIS MSCG meeting). The main issues addressed and tackled in this workshop’s report are: - Common lists of elements for the biodiversity assessments (species & habitats) o Review of the “Biological Features” in Table 1 in the MSFD Annex III in relation to D1 requirements o Review of the “Habitat Types” entries in Table 1 in the MSFD Annex III in relation to D1 requirements - Selection/deselection criteria for the inclusion of species and habitats in a group - Updated criteria and indicators for D1 - Habitat/Bird Directives, WFD, Common Fisheries Policy and D1 o Use of species and habitats for the MSFD needs that are already included in other legislation and agreements o Links between status classification approaches (FCS vs GES, GEcS vs GES) - Streamlining of assessments, including scales of assessments - Cross-cutting issues related to D1 implementation o Aggregation rules within D1 criteria/indicators o Final GES integration across descriptors assessments Steps forward and technical needs for D1.JRC.H.1-Water Resource

Achievement of the planetary defense investigations of the Double Asteroid Redirection Test (DART) mission

NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by –33.24 minutes, with two independent analysis methods each reporting a 1σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos–Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense

Modelling the effects of fishing on the North Sea fish community size composition

Ecosystem-based management of the North Sea demersal fish community uses the large fish indicator (LFI), defined as the proportion by weight of fish caught in the International Bottom Trawl Survey (IBTS) exceeding a length of 40 cm. Current values of the LFI are similar to 0.15, but the European Union (EU) Marine Strategy Framework Directive (MSFD) requires a value of 0.3 be reached by 2020. An LFI calculated from an eight-species subset correlated closely with the full community LFI, thereby permitting an exploration of the effects of various fishing scenarios on projected values of the LFI using an extension of a previously published multi-species length-structured model that included these key species. The model replicated historical changes in biomass and size composition of individual species, and generated an LFI that was significantly correlated with observations. A community-wide reduction in fishing mortality of 60% from 2008 values was necessary to meet the LFI target, driven mainly by changes in cod and saithe. A 70% reduction in cod fishing mortality alone, or a 75% reduction in otter trawl effort, was also sufficient to achieve the target, Reductions in fishing mortality necessary to achieve maximum sustainable harvesting rates are projected to result in the LFI over-shooting its target

Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community

Broader ecosystem management objectives for North Sea demersal fish currently focus on restoring community size structure. However, most policy drivers explicitly concentrate on restoring and conserving biodiversity, and it has not yet been established that simply restoring demersal fish size composition will be sufficient to reverse declines in biodiversity and ensure a generally healthy community. If different aspects of community composition, structure, and function vary independently, then to monitor all aspects of community general health will require application of a suite of metrics. This assumes low redundancy among the metrics used in any such suite and implies that addressing biodiversity issues specifically will require explicit management objectives for particular biodiversity metrics. This issue of metric redundancy is addressed, and 15 metrics covering five main attributes of community composition, structure, and function are applied to groundfish survey data. Factor analysis suggested a new interpretation of the metric information and indicated that a minimum suite of seven metrics was necessary to ensure that all changes in the general health of the North Sea demersal fish community were monitored properly. Covariance among size-based and species-diversity metrics was low, implying that restoration of community size structure would not necessarily reverse declines in species diversity