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The benefits of physiological biomarkers, knowledge and concepts are well-established in fish and wildlife management as they confer the ability to understand mechanistic processes, identify cause-and-effect relationships, and develop predictive models. Although this approach is gaining momentum in the context of species conservation, the use of physiological biomarkers in exploited marine fish stock management and recovery plans remains relatively rare. Here, we present five essential issues to consider to implement physiological biomarkers in fisheries management: (i) choice of relevant biomarkers that have a well-known mechanistic basis, (ii) identification of species-specific biomarkers reflecting a meaningful timespan for management, (iii) selection of biomarkers compatible with data collection during routine scientific fisheries surveys, (iv) use of biomarkers as early-warning signals and complementary indicators of population-level changes in life history traits and (v) how physiological biomarkers may help to refine long-term population dynamic projections under climate change and management scenarios. Overall, if based on well-established mechanisms linked to individuals' fitness, a focus on physiological biomarkers should help to better understand the mechanisms behind stock declines, changes in stock characteristics, and thus more efficiently manage marine fisheries and conserve populations. As this approach is transferable among species, locations, and times, the integration of physiological biomarkers in fisheries science has the potential to more broadly enhance assessments and management of fish stocks. [ABSTRACT FROM AUTHOR]

Ecosystem-based approaches are increasingly used in fisheries management to account for the direct trophic impacts of fish population harvesting. However, fisheries can also indirectly alter ecosystem structure and functioning, for instance via the provision of new feeding opportunities to marine predators. For instance, marine depredation, where predators feed on fishery catches on fishing gear, is a behaviour developed by many marine species globally. This behaviour can modify both the ecological role of predators and fisheries performance. Yet, these ecosystem-wide effects of depredation are rarely considered holistically. In this study, we explored different ways of incorporating depredation into an Ecopath trophic model. We assessed, through a subantarctic case study, how three alternative model structures can account for depredation effects on fishery catches, predator and non-commercial prey populations, as well as target fish stocks. While none adequately addresses all facets of depredation, the alternative models can to some extent capture how depredation can lead to increased fishing pressure on stocks. As structural specificities of Ecopath prevented us from representing other depredation effects such as provisioning effects for predator populations, we conclude this study with a set of guidance to effectively capture the complex effects of depredation in marine ecosystems and fisheries models. [ABSTRACT FROM AUTHOR]

Sustainable fisheries management requires assessment of exploited populations and communities. Traditional fisheries stock assessment methods need species‐specific input data, which for skates have only recently become available in Europe. To overcome this limitation, a Bayesian multispecies biomass production model was developed. In addition to aggregated landings, input data are short time series with species‐specific information (landings and biomass indices). Applying the approach to four main skate species and a group of two skate species, all managed together in the Bay of Biscay (Northeast Atlantic), long‐term changes in the skate assemblage composition were identified. Since the 1990s, Leucoraja naevus became increasingly dominant, while the contributions of the other three species (Raja brachyura, Raja clavata and Raja montagui) declined. The abundance of the grouped Leucoraja fullonica and L. circularis has also strongly decreased, suggesting long‐term overexploitation. All species except this species group are expected to increase over the next decade under current harvest rates. Currently, the species considered here are managed under a single fishing quota making it unlikely that the group of the two most depleted species will recover soon. The multispecies modelling approach bears promise for other harvested assemblages for which only grouped harvest information is available for certain periods. [ABSTRACT FROM AUTHOR]

We present a framework for evaluating fisheries management plans comprehensively, both rebuilding plans and others. The framework includes a first rapid appraisal of the likelihood that the plan will result in management meeting its objectives, and guides subsequent quantitative analyses of potential weaknesses in the proposed plan. The framework includes four steps: (i) evaluating if a set of management objectives, if achieved, would result in a sustainable fishery, (ii) using qualitative analysis of a bio-economic model to evaluate whether the set of stock management tactics might be capable of achieving the specified fisheries objectives, (iii) using empirical criteria derived from the literature to evaluate if other management measures in the plan related to the ecological, social or economic context of the fishery actually contribute to sustainability, and (iv) carrying out quantitative simulations to compare alternative implementation options. Generally, several management measures have to be combined to increase stock size without sacrificing the economic benefits to the fishers remaining in the fishery. We demonstrate application of the framework for evaluating the stock rebuilding plan for plaice ( Pleuronectes platessa) and sole ( Solea solea) in the North Sea and, the management measures currently in place for the roundnose grenadier ( Coryphaenoides rupestris) stock exploited to the west of the British Isles. [ABSTRACT FROM AUTHOR]

To implement an ecosystem approach to fisheries management, there is a need to characterize the total pressure exerted by fisheries at the community level. French onboard observer data were used to derive catch metrics and compare fishing distribution across community components between two sites in the Southern Bay of Biscay. Sample-based rarefaction curves were used to standardize metrics across different active and passive gears, and correct for sample size differences. Six metrics for species, length and functional catch composition were tested. Length and functional metrics were found the most relevant metrics to highlight differences in catches between gears, sites, and gear-site interactions. Significant differences were found between gears, mainly in mean length and proportion of piscivores. None of the gears had the most diverse catch across all metrics. Small differences were found between sites, mainly in length range and species richness. [ABSTRACT FROM AUTHOR]

Lorance, P., Agnarsson, S., Damalas, D., des Clers, S., Figueiredo, I., Gil, J., and Trenkel, V. M. 2011. Using qualitative and quantitative stakeholder knowledge: examples from European deep-water fisheries. – ICES Journal of Marine Science, 68: 1815–1824.Stakeholder knowledge was collected through questionnaires and cognitive maps and used to summarize biological, environmental, technical, management, and socio-economic factors for several deep-water fisheries, identifying regional management issues and solutions. The questionnaires and cognitive maps revealed different technical, environmental, and management concerns in these fisheries. Dissatisfaction with management was more at an implementation than a conceptual level, because the existing management measures were mostly considered fit for purpose. Further, catch-and-effort data provided by the fishing industry were used to calculate standardized landings per unit effort. The results suggested different trends over time for three deep-water stocks exploited by the same fleet. The examples demonstrate how stakeholder involvement and use of qualitative knowledge and quantitative data might improve the management process and stock assessments when data are limited. [ABSTRACT FROM PUBLISHER]

Blanchard, J. L., Coll, M., Trenkel, V. M., Vergnon, R., Yemane, D., Jouffre, D., Link, J. S., and Shin, Y-J. 2010. Trend analysis of indicators: a comparison of recent changes in the status of marine ecosystems around the world. – ICES Journal of Marine Science, 67: 732–744.Time-series of ecological and exploitation indicators collected from 19 ecosystems were analysed to investigate whether there have been temporal trends in the status of fish communities. Using linear and non-linear statistical methods, trends are reported for six indicators (mean length of fish in the community, mean lifespan, proportion of predatory fish, total biomass of surveyed species, mean trophic level of landings, and inverse fishing pressure), and the redundancy of these indicators across ecosystems is evaluated. The expected direction of change for an ecosystem that is increasingly impacted by fishing is a decline in all indicators. A mixture of negative and positive directions of change is recorded, both within and among all ecosystems considered. No consistent patterns in the redundancy of the ecological indicators across ecosystems emerged from the analyses, confirming that each indicator provided complementary information on ecosystem status. The different trends in indicators may reflect differing historical exploitation patterns, management, and environmental regimes in these systems. Commitment to monitoring programmes and development of system-specific baseline, target, and threshold reference levels are required. Improved understanding of the responsiveness and performance of ecological indicators to management actions are needed to address adequately whether ecosystems are recovering from, or being further impacted by, fishing, and whether management targets are being met. The relative effects of multiple environmental and ecological processes as well as multiple human-induced stressors that characterize exploited ecosystems also need to be quantified. [ABSTRACT FROM PUBLISHER]

This paper provides an overview of the progress Ifremer has made recently in fisheries acoustics and the study of small pelagic fish by: i) pushing observation frontiers using a range of platforms including an autonomous underwater vehicle, AUV, ii) developing measuring instruments and methods and iii) studying fish distributions. Presently, information from several frequencies of single-beam echosounders is routinely collected together with data from the ME70 multibeam echosounder. For onboard data acquisition control the HERMES software was developed. The new MOVIES 3D software includes modules for simultaneous realistic 3D visualisation and post-processing such as bottom detection, school extraction and calculation of descriptors and integration of all acoustic data. Several data analysis methods are being developed and some initial results are presented. Finally, results on the spatial distribution of small pelagic fish schools in the Bay of Biscay illustrate the role that acoustics can play, and are already playing, in the implementation of an ecosystem approach to fisheries. [ABSTRACT FROM AUTHOR]

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Copyright of Aquatic Living Resources is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Using indicator time series for assessment and management requires methods for characterising recent time trends. We propose an approach where first the indicator time series is smoothed using a generalised additive model with optimal selection of the degree of smoothness. Second an intersection–union test is carried out using two test statistics which are the occurrence of the global maximum (or minimum) within the most recent years and the signs of the estimated annual first derivatives of the smoothed indicator times series during the same period, including years with missing data. The proposed test is applied to fish abundance indices for the North Sea, for which it is they are able to pick up changes happening during the last 3–5 years in contrast to linear regression and the Mann–Kendall test which find much fewer significant recent trends. An additional test for changes in trends using the second derivatives of the smoothed indicator time series provide early warnings for subsequent trends for certain species. [Copyright &y& Elsevier]

Ecosystem assessments of fisheries based only on survey data will often have to use surveys that were designed historically for special purposes, e.g. for assessing abundances of two or three target species, or for tuning VPAs. An important question then is whether the previously collected data can provide informative time series of abundance indices and other state indicators for a wider range of target and non-target species. Some potential shortcomings of existing data series are treated in this paper leading to four questions which can guide the user to determine the suitability of an existing time series: did the survey cover the stock of each species adequately? Did survey catchability vary significantly between length or age classes? Did survey catchabilities vary significantly in space or time? Was the sampling effort sufficient? Simple methods for investigating these questions are proposed and illustrated with examples. [ABSTRACT FROM AUTHOR]

Ideas and considerations are put forward for managing fisheries and marine populations using primarily trawl surveys to supply biological and spatial indicators of the state of stocks, and to permit catch per unit effort (CPUE)-based assessments. Trawl surveys seldom allow absolute estimates of fish population sizes but, if appropriately located, timed, and designed, can provide a broad range of information about catchable fish species and the ecosystem that supports them. This information may be more conducive to sustainable management of fisheries than the traditional focus on the abundances of selected stocks. The paper first briefly proposes how survey-based methods might supplement existing fishery-dependent stock assessments, as would be necessary during a transition phase to a more ecosystem-orientated system of management. Full survey-based management is then considered in relation to management objectives, the selection of indicators, survey design, reference periods, levels and directions, statistical aspects, CPUE-based assessments, and management responses to good and bad signals from the ecosystem. We argue that existing fishery-dependent stock assessments cannot be claimed to produce absolute estimates of stock abundance and fishing mortality because natural mortality (M) is seldom known accurately and, therefore, that they should not be presumed superior to the relative information from surveys, and an agreeable form of adaptive management. [ABSTRACT FROM AUTHOR]

Rochet, M-J., Prigent, M., Bertrand, J. A., Carpentier, A., Coppin, F., Delpech, J-P., Fontenelle, G., Foucher, E., Mahé, K., Rostiaux, E., and Trenkel, V. M. 2008. Ecosystem trends: evidence for agreement between fishers' perceptions and scientific information. – ICES Journal of Marine Science, 65: 1057–1068.The results of a survey on fishers' perceptions of recent changes in the eastern English Channel ecosystem carried out in 2006 were compared with fishery and bottom-trawl survey data. A hypothesis-testing framework was used, testing the null hypothesis that fishers' statements were true, which permitted evaluation of both agreement and disagreement. Overall good agreement between fishers' statements and scientific data was found, and both sources suggested that the fish community in the Channel is undergoing large changes, among which are decreases in some commercially important species; in addition, a number of human pressures impact the ecosystem. Fishers had an accurate perception of changes and their time-frames, but not necessarily of their causes. They had a greater power than survey data to detect recent changes, showing that fishers' perceptions have great potential as early warning signals. [ABSTRACT FROM PUBLISHER]

Trenkel, V. M., Rochet, M-J., and Mesnil, B. 2007. From model-based prescriptive advice to indicator-based interactive advice. – ICES Journal of Marine Science, 64: 768–774. Traditional advice for fisheries management, especially in the ICES world, focuses on short-term stock projections relative to reference points. Primarily, two numbers, spawning-stock biomass and fishing mortality rate, are considered in the advice, although a range of biological processes are included in the stock assessment models. We propose an alternative form of final advice that would not rely on stock predictions and only two numbers, but on a suite of indicators that are combined to provide stock assessment and management advice. For a single stock, the approach consists of monitoring a set of indicators of population state and fishing pressure. Stock reference status at some time in the past is assessed, based on these indicators and/or other available information. Changes in indicator values after this reference time are then estimated, interpreted, and finally combined into a diagnostic that highlights possible causes of the changes observed. After considering management objectives, appropriate management actions can then be proposed. The proposed approach is illustrated for anglerfish stocks in the Celtic Sea and the Bay of Biscay. [ABSTRACT FROM PUBLISHER]

Abstract: For fisheries management purposes, it is essential to take into account spatial and seasonal characteristics of fishing activities to allow a reliable assessment of fishing impact on resource. This paper presents a novel technique for describing spatial and temporal patterns in fishing effort. The spatial and seasonal fishing activity patterns of the French trawler fleet in the Celtic Sea during the period 1991–1998 were analysed by modelling fishing effort (fishing time) with generalised linear models. The linear model for fishing effort included fixed effects for both spatial (statistical rectangles) and temporal units (months). In addition, spatial correlations in any given month were modelled by an exponentially decreasing function. Temporal correlations were included using the previous month''s fishing effort for a given spatial unit as predictor. A method based on cluster analysis of estimated model coefficients of spatial or temporal fixed effects is proposed for identifying groups of similar spatial and temporal units. A contiguity constraint is imposed in the clustering algorithm, ensuring that only neighbouring spatial units or consecutive temporal units are grouped. The cluster analysis identified 22 spatial and 9 temporal groups. Winter and spring months stood out as being more variable than the remaining months. Spatial groups were of varying size, and generally larger offshore. The proposed method is generic and could for example be used to analyse temporal and spatial patterns in catch or catch rate data. [Copyright &y& Elsevier]