Ocean Futures Under Ocean Acidification, Marine Protection, and Changing Fishing Pressures Explored Using a Worldwide Suite of Ecosystem Models

Ecosystem-based management (EBM) of the ocean considers all impacts on and uses of marine and coastal systems. In recent years, there has been a heightened interest in EBM tools that allow testing of alternative management options and help identify tradeoffs among human uses. End-to-end ecosystem modeling frameworks that consider a wide range of management options are a means to provide integrated solutions to the complex ocean management problems encountered in EBM. Here, we leverage the global advances in ecosystem modeling to explore common opportunities and challenges for ecosystem-based management, including changes in ocean acidification, spatial management, and fishing pressure across eight Atlantis (atlantis.cmar.csiro.au) end-to-end ecosystem models. These models represent marine ecosystems from the tropics to the arctic, varying in size, ecology, and management regimes, using a three-dimensional, spatially-explicit structure parametrized for each system. Results suggest stronger impacts from ocean acidification and marine protected areas than from altering fishing pressure, both in terms of guild-level (i.e., aggregations of similar species or groups) biomass and in terms of indicators of ecological and fishery structure. Effects of ocean acidification were typically negative (reducing biomass), while marine protected areas led to both “winners” and “losers” at the level of particular species (or functional groups). Changing fishing pressure (doubling or halving) had smaller effects on the species guilds or ecosystem indicators than either ocean acidification or marine protected areas. Compensatory effects within guilds led to weaker average effects at the guild level than the species or group level. The impacts and tradeoffs implied by these future scenarios are highly relevant as ocean governance shifts focus from single-sector objectives (e.g., sustainable levels of individual fished stocks) to taking into account competing industrial sectors\u27 objectives (e.g., simultaneous spatial management of energy, shipping, and fishing) while at the same time grappling with compounded impacts of global climate change (e.g., ocean acidification and warming)

Converging and diverging burn rates in North American boreal forests from the Little Ice Age to the present

Warning. This article contains terms, descriptions, and opinions used for historical context that may be culturally sensitive for some readers. Background. Understanding drivers of boreal forest dynamics supports adaptation strategies in the context of climate change. Aims. We aimed to understand how burn rates varied since the early 1700s in North American boreal forests. Methods. We used 16 fire-history study sites distributed across such forests and investigated variation in burn rates for the historical period spanning 1700-1990. These were benchmarked against recent burn rates estimated for the modern period spanning 1980-2020 using various data sources. Key results. Burn rates during the historical period for most sites showed a declining trend, particularly during the early to mid 1900s. Compared to the historical period, the modern period showed less variable and lower burn rates across sites. Mean burn rates during the modern period presented divergent trends among eastern versus northwestern sites, with increasing trends in mean burn rates in most northwestern North American sites. Conclusions. The synchronicity of trends suggests that large spatial patterns of atmospheric conditions drove burn rates in addition to regional changes in land use like fire exclusion and suppression. Implications. Low burn rates in eastern Canadian boreal forests may continue unless climate change overrides the capacity to suppress fire.Peer reviewe

An integrated environmental and human systems modeling framework for Puget Sound restoration planning

Local, state, federal, tribal and private stakeholders have committed significant resources to restoring Puget Sound’s terrestrial-marine ecosystem. Though jurisdictional issues have promoted a fragmented approach to restoration planning, there is growing recognition that a more coordinated systems-based restoration approach is needed to achieve recovery goals. This presentation describes our collaborative effort to develop and apply an integrated environmental and human systems modeling framework for the Puget Sound Basin, inclusive of all marine and land areas (1,020 and 12,680 sq. mi.). Our goal is to establish a whole-basin systems modeling framework that dynamically simulates biophysical interactions and transfers (water, nutrients, contaminants, biota) across terrestrial-marine boundaries. The core environmental models include a terrestrial ecohydrological model (VELMA), an ocean circulation and biogeochemistry model (Salish Sea Model), and an ocean food web model (Atlantis). This environmental subsystem will be linked with an agent-based modeling subsystem (e.g., Envision) that allows human decision-makers to be represented in whole-basin simulations. The integrated environmental and human systems framework aims to facilitate discourse among different stakeholders and decision makers (agents) and enable them play out the ecological, social and economic consequences of alternative ecosystem restoration choices. All of these models are currently being applied in Puget Sound, but they have not yet been integrated. The linked models will better capture the propagation of human impacts throughout the terrestrial-marine ecosystem, and thereby provide a more effective decision support tool for addressing restoration of high priority environmental endpoints, such as the Vital Signs identified by the Puget Sound Partnership (http://www.psp.wa.gov/vitalsigns/). Our overview will include examples of existing stand-alone model applications, and conceptual plans for linking models across terrestrial-marine boundaries. The Puget Sound multi-model framework described here can potentially be expanded to address the entire Salish Sea transboundary ecosystem (https://www.eopugetsound.org/maps/salish-sea-basin-and-water-boundaries)

Ecosystem and fishers’ behaviour modelling: two crucial and interacting approaches to support Ecosystem Based Fisheries Management in the Eastern English Channel

The implementation of the ecosystem approach to fisheries management (EAFM) requires an enhancement of our knowledge of ecosystem complexity. Understanding the ecosystem reaction to management regulation is a key to achieve conservation objectives. Ecosystem modelling improves our knowledge on ecosystem functioning in interaction with human activities, and it is now widely used to evaluate management strategies. The fishers’ behaviour of the French demersal fisheries in the Eastern English Channel (EEC) has been investigated. Results showed that fishers tended to adhere to past annual fishing practices and maritime traffic may impact on fishing decision. A global analysis of the fisheries science literature during the last three decades evidenced the influence of tradition and species targeting in fishers’ behaviour. The exploration of ecosystem dynamics required the use of the ecosystem model Atlantis with a focus on two commercial flatfish species, sole (Solea solea) and plaice (Pleuronectes platessa). The importance of estuary areas and of nutrient inputs has been revealed as well as the role of discards and of two key species, cod (Gadus morhua) and whiting (Merlangius merlangius). Sole and plaice did not have a strong influence on the trophic network excepted on benthic invertebrate dynamics. Finally, we investigated the consequences of area closure and effort reduction on fishers’ behaviour and the ecosystem impacted. We observed a noticeable benefit of combining area closure and effort reduction on the biomass of most commercial species and on the total value landed per unit effort.La mise en place de l’approche écosystémique des pêches (AEP) requiert une amélioration de nos connaissances sur la complexité des écosystèmes. Comprendre la réaction de l’écosystème à des mesures de gestion est essentiel pour atteindre les objectifs de conservation. La modélisation écosystémique a amélioré nos connaissances sur le fonctionnement des écosystèmes et leurs interactions avec les usages du domaine maritime; et est de plus en plus utilisée pour évaluer l’impact de mesures de gestion. Le comportement de pêche des flottilles démersales françaises en Manche Orientale a été analysé. Les résultats montrent que les pêcheurs conservent leurs habitudes de pêches et que le trafic maritime peut impacter leurs décisions. Une analyse globale des résultats d’études menées au cours des trente dernières années démontre l’influence des habitudes et des espèces ciblées sur le comportement de pêche. L’exploration de la dynamique de l’écosystème a nécessité l’utilisation du modèle Atlantis, en focalisant sur deux espèces commerciales, la sole (Solea solea) et la plie (Pleuronectes platessa). L’importance des zones estuariennes est révélée, ainsi que le rôle joué par les rejets et par deux espèces clés, la morue (Gadus morhua) et le merlan (Merlangius merlangius). La sole et la plie ont peu d’influence sur le réseau trophique excepté sur la dynamique des invertébrés benthiques. Nous évaluons les conséquences de l’application de fermeture de zones et d’une réduction d’effort sur le comportement de pêche et l’écosystème et mettons en évidence un bénéfice de l’application combinée de ces mesures sur la biomasse des espèces commerciales et sur la valeur débarquée par unité d’effort

French data processing for assessment working groups

During the flatfish benchmark held in ICES in 2020 (WKFlatNSCS), questions arose on the modifications made recently on two key fields of fisheries data processed by France for providing data to stock assessment groups. These two fields are: • the gap filling method in Age Length Keys • the effort aggregates in support of discards raising procedure Updates of procedures, improvements of R scripts and coding are done permanently, and some of the modifications made in 2019 at the demand of WGNSSK experts had unraveled issues that went undetected until data submission of sol.27.7d full time series for WKFlatNSCS benchmark. These issues may have also impacted the Celtic Sea benchmark (WKCELTIC) and to a lesser extent the WKDEM earlier in the year.  The document is meant to bring clarity in the procedure used recently, the differences it made on the final estimates of discards and age structures, and propose a way to fix the issues.Lors du benchmark sur les poissons plats organisé par le CIEM en 2020 (WKFlatNSCS), des questions ont été soulevées sur les modifications apportées récemment sur deux domaines clés des données de pêche traitées par la France pour fournir des données aux groupes d'évaluation des stocks. Ces deux domaines sont les suivants - la méthode de comblement des lacunes dans les clés taille-âge - les agrégats d'effort à l'appui de la procédure d'élévation des rejets Les mises à jour des procédures, les améliorations des scripts R et du codage sont effectuées en permanence, et certaines des modifications apportées en 2019 à la demande des experts du WGNSSK ont généré des problèmes qui n'avaient pas été détectés jusqu'à la soumission des données de la série temporelle complète sol.27.7d pour le benchmark WKFlatNSCS. Ces problèmes peuvent également avoir eu un impact sur le benchmark des gadidés de la mer Celtique (WKCELTIC) et, dans une moindre mesure, sur le WKDEM en début d'année.  Le document vise à clarifier la procédure utilisée récemment, les différences qu'elle a pu produire sur les estimations finales des rejets et des structures d'âge, et à proposer une manière de résoudre ces problèmes

Detection of fishing pressure using ecological network indicators derived from ecosystem models

Marine ecosystems are exposed to multiple stressors, mainly fisheries that, whenever mismanaged, may cause irreversible damages to whole food webs. Ecosystem models have been applied to forecast fisheries impact on fish stocks and marine food webs. These impacts have been studied through the use of multiple indicators that help to understand ecosystem responses to stressors. This study focused on a category of ecological indicators derived from the network theory to quantify energy flows inside the food web. These indicators were computed using two ecosystem models applied to the Eastern English Channel (i.e. Atlantis and OSMOSE). This work aimed at investigating how several ecological network indicators respond to different levels of fishing pressure and evaluating their robustness to model structure and fishing strategies. We applied a gradient of fishing mortality using two ecosystem models and carried out ecological network analysis to obtain network-derived indicators. The results revealed that the indicators response is highly driven by the food web structure, although the model assumptions buffered some results. The indicators computed from OSMOSE outputs were more sensitive to changes in fishing pressure than those from Atlantis. However, once the food web from Atlantis was simplified to mimic the structure of OSMOSE model, the indicators of the modified Atlantis became more sensitive to the intensity of fishing pressure. The indicators related to amount of energy flow and to the organization of the flows in the food web were sensitive to the increase of fishing mortality for all fishing strategies. These indicators suggested that increasing fishing mortality jeopardizes the amount of energy mobilized by the food webs and simplifies the ecological interactions, which has implications for the resilience of marine ecosystems. The study shed light on the trophic networks structure and functioning of the ecosystems whenever exposed to disturbances. Furthermore, these indicators might be adequate for whole ecosystem assessments of health and contribute to ecosystem management

Predicting fisher response to competition for space and resources in a mixed demersal fishery

Understanding and modelling fleet dynamics and their response to spatial constraints is a prerequisite to anticipating the performance of marine ecosystem management plans. A major challenge for fisheries managers is to be able to anticipate how fishing effort is re-allocated following any permanent or seasonal closure of fishing grounds, given the competition for space with other active maritime sectors. In this study, a Random Utility Model (RUM) was applied to determine how fishing effort is allocated spatially and temporally by the French demersal mixed fleet fishing in the Eastern English Channel. The explanatory variables chosen were past effort i.e. experience or habit, previous catch to represent previous success, % of area occupied by spatial regulation, and by other competing maritime sectors. Results showed that fishers tended to adhere to past annual fishing practices, except the fleet targeting molluscs which exhibited within year behaviour influenced by seasonality. Furthermore, results indicated French and English scallop fishers share the same fishing grounds, and maritime traffic may impact on fishing decision. Finally, the model was validated by comparing predicted re-allocation of effort against observed effort, for which there was a close correlation

Reconciling complex system models and fisheries advice: Practical examples and leads

The move toward an ecosystem-based fisheries management (EBFM) requires new operational tools in order to support management decisions. Among them, ecosystem- and fisheries-based models are critical to quantitatively predict the consequences of future scenarios by integrating available knowledge about the ecosystem across different scales. Despite increasing development of these complex system models in the last decades, their operational use is still currently limited in Europe. Many guidelines are already available to help the development of complex system models for advice yet they are often ignored. We identified three main impediments to the use of complex system models for decision support: (1) their very complexity which is a source of uncertainty; (2) their lack of credibility, (3) and the challenge of communicating/transferring complex results to decision makers not accustomed to deal with multivariate uncertain results. In this paper, we illustrate these somehow theoretical “best practices” with tangible successful examples, which can help the transfer of complex system models from academic science to operational advice. We first focus on handling uncertainty by optimizing model complexity with regards to management objectives and technical issues. We then list up methods, such as transparent documentation and performance evaluation, to increase confidence in complex system models. Finally, we review how and where complex system models could fit within existing institutional and legal settings of the current European fisheries decision framework. We highlight where changes are required to allow for the operational use of complex system models. All methods and approaches proposed are illustrated with successful examples from fisheries science or other disciplines. This paper demonstrates that all relevant ingredients are readily available to make complex system models operational for advice

Rapport annuel 2021 de l’Unité Halieutique Manche – Mer du Nord (HMMN)

L’Unité de recherche HMMN, créée en 2005, appartient depuis 2011 au Département Ressources Biologiques et Environnement (RBE), qui est l’un des 4 Département scientifiques de l’IFREMER, avec les Départements Océanographie et Dynamique des Ecosystèmes (ODE), Recherches physiques et Ecosystèmes de fond de Mer (REM) et Infrastructures de Recherche et Systèmes d’Information (IRSI). L’Unité de recherche HMMN est constituée de deux laboratoires, l’un situé à Boulogne sur mer dans les Hauts de France (LRHBL) et l’autre à Port-en-Bessin en Normandie (LRHPB). Ces deux laboratoires, ainsi que les autres laboratoires des Départements ODE et REM localisés à Boulogne s/mer et Port-en-Bessin (ODE: deux Laboratoires Environnement Ressources, LERBL et LERN; REM: un Laboratoire Comportement des Structures en Mer, LCSM), sont rattachés administrativement au Centre de Manche – Mer du Nord (CMMN) de l’IFREMER. L’équipe HMMN effectue des recherches en écologie marine et halieutique, principalement centrées sur les écosystèmes de Manche et Sud mer du Nord. Ces recherches trouvent un prolongement dans l’appui aux politiques publiques concernant la conservation des écosystèmes marins et l’aménagement des pêcheries et d’autres usages du domaines maritime (e.g., extraction de sables et granulats marins, production d’énergies marines renouvelables), dans un contexte de changement climatique. L’unité HMMN contribue à la collecte de données halieutiques et écosystémiques en mer, par enquêtes, et en laboratoire, et centralise à travers la cellule CREDO, le traitement et l’envoi des données halieutiques requises par une variété d’organismes scientifiques, gestionnaires, professionnels et non gouvernementaux. HMMN coordonne trois campagnes en mer à grande échelle régionale et héberge trois infrastructures technologiques: un Pôle National de Sclérochronologie (PNS), une Plateforme Réseaux Trophiques (PRT), et un Pôle de Taxinomie et d’Ecologie du Zooplancton (PTEZOO). En cherchant à mieux comprendre les interactions entre les ressources halieutiques et leur environnement (biotique et abiotique), dans un contexte de changement global, l’unité HMMN contribue spécifiquement à plusieurs des enjeux définis dans le projet de l’institut: E6 (Évaluer le devenir des écosystèmes côtiers dans le changement global), E9 (Identifier les effets des interactions entre groupes fonctionnels sur la dynamique des écosystèmes exploités), E10 (Évaluer la résilience et anticiper les changements d’état – points de basculement des socio-écosystèmes et de la biodiversité associée aux différents niveaux d’organisation), et E13 (Identifier de nouvelles bioressources marines). Ces enjeux sont déclinés au sein de l’Unité dans trois Thèmes scientifiques correspondant à des niveaux d’organisation systémique de plus en plus complexes : Individus, Populations et Niches Ecologiques (Thème 1); Communautés, Réseaux Trophiques et Biodiversité (Thème 2); Flottilles, Exploitation et Scénarios de Gestion (Thème 3). Les approches méthodologiques menées en 2021 pour améliorer notre compréhension des processus ont utilisé et/ou combiné des analyses empiriques de données d’observation in-situ, expérimentales et de modélisation, ces dernières étant directement liées à deux défis du projet d’Institut : D2 (l’expérimentation pour améliorer notre compréhension des processus) et D3 (la modélisation prédictive intégrée des socio-écosystèmes). Enfin, l’unité HMMN a joué en 2021, comme au cours des années précédentes, un rôle de catalyseur pour les sciences marines au niveau régional d’une part dans les Hauts-de-France comme membre actif de la Fédération de Recherche Campus de la Mer, l’un des chefs de file de projets CPERs et enfin comme unité participant à l’École universitaire de recherche transdisciplinaire pour les sciences marines, l’halieutique et les produits de la mer (Transdisciplinary graduate school for marIne, Fisheries and SEAfood sciences, IFSEA) mis en place en 2021 dans le cadre des PIA4 de l’Agence Nationale de la Recherche (ANR) et d’autre part en Normandie comme membre de la Fédération de Recherche Merlin. De plus, l’unité HMMN a continué à renforcer son implication dans les régions ultrapériphériques (RUP), avec plusieurs projets comme Accobiom ciblant la Guadeloupe, la Martinique, la Guyane et la Réunion mais aussi à travers de nombreux travaux et expertises menés à Saint-Pierre et Miquelon. Enfin, au niveau international, l’unité HMMN contribue aussi au rayonnement de l’IFREMER au travers de recrutements (chercheurs, post-doctorants, étudiants en thèse) et de l’implication à haut niveau de chercheurs HMMN dans des projets de recherche européens et de groupes de travail structurants (e.g., présidence de GTs du CIEM, du CSTEP, de RCGs, experts nommés pour le GIEC ou l’IPBES). En 2021, de nouveaux projets structurants pour l’unité HMMN ont été acceptés (e.g, CPER IDEAL, FORESEA 2050, MAESTRO, SAR, CARPARC, IPREM, ACCOBIOM). Une thèse a été soutenue 2021 avec succés et deux nouvelles thèses ont démarré. L’équipe a également maintenu son niveau d’engagement dans l’APP, qu’il s’agisse d’avis et expertises (nécessitant dans le cadre de certains Groupes de Travail internationaux des visioconférences de plus d’une réunion en présentiel), ou de réalisation de campagnes à la mer (IBTS, CGFS, COMOR, DCSMM, IGA)