Ecospace Model Research Articles

Addressing offshore wind farms compatibilities and conflicts with marine conservation through the application of modelled benchmarking scenarios

Offshore wind power generation structures are scheduled for development in the Canary Islands, potentially resulting in spatial overlap with various maritime activities, particularly fishing. It is crucial to point out that some areas that are considered suitable for installing these structures are in protected zones that are part of the Natura 2000 network, and do not have any prior environmental impact assessments. The research delved into the efficacy of utilizing Ecopath with Ecosim software to examine the consequences of implementing this technology in the study area, employing an ecosystem-based approach. To address this question, simulations were executed by assessing three distinct scenarios. The results suggest that there would be changes in the distribution of keystone species such as top predators, alongside a conspicuous decline in the abundance and catches of target species of the fishery. The Ecospace model holds the potential to forecast the impacts of offshore wind installations; however, crucial factors must be carefully considered, such as the lack of information. Notwithstanding the constraints, research like this demonstrates the efficacy of spatial ecosystem modelling in exploring this issue.

Retrospective analysis of the pelagic ecosystem of the Western Mediterranean Sea: Drivers, changes and effects

In the Western Mediterranean Sea, forage fishes have changed in abundance, body condition, growth, reproduction, and distribution in the last decades. Different hypotheses have been proposed to explain these changes, including increase in fishing mortality; changes in environmental conditions affecting species fitness, and planktonic productivity and quality; recovery of top predators; and increase in competitors. We investigated the main drivers and changes of the pelagic ecosystem and their effects using an ecosystem-based modelling approach. Specifically, we (1) quantified the potential historical contribution of various drivers of change, (2) investigated changes in temporal trends and spatial distributions of main ecosystem components, and (3) identified ecological consequences of these changes in top predator and competitors, their fisheries and ecosystem traits during 2000–2020. We updated an established Ecopath food-web model representing the Spanish and French Mediterranean sub-areas (GSA06 and GSA07) in 2000 with recent available data. We applied the temporal dynamic Ecosim module, and tested historical time series of fishing effort, fishing mortality and environmental factors as potential drivers. Observed biomass and landings of key species were used to validate model projections. A spatial-temporal Ecospace model was developed to project species distribution changes. Results showed historical biomass and catch changes driven by a combination of high fishing pressure and environmental change (i.e. increase in temperature and salinity, and decline in primary productivity). Small pelagic fish showed significant temporal changes and predicted shifts in their distributions, following a latitudinal gradient. Predators and competitors showed changes as well, displaying heterogeneous spatial patterns, while fisheries landings declined. Overall, results matched observations (e.g., decline of sardine, fluctuations of anchovy and increases in bluefin tuna) and illustrated the need to complement traditional assessments with integrative frameworks to move towards an ecosystem-based approach in the Mediterranean. They also highlighted important knowledge gaps to guide future research in the region.

Modelling the spatial shifts of functional groups in the Barents Sea using a climate-driven spatial food web model

We built a dynamic, spatial food web model for the Barents Sea, developed with Ecospace by including species’ habitat requirements and ecological interactions. The model was used to test the spatial shifts of different functional groups due to warming. We compared model-predicted and field-surveyed biomass of functional groups (FGs) spatial distributions in relatively cold and warm years. The Ecospace model included habitat foraging capacities for environmental parameters such as water temperature and bottom depth for 74 FGs out of a total of 108 FGs. We created two plausible scenarios, one representing a relatively cold year (2004) and another representing a warm year (2013) with differences of ca. 0.3 °C in bottom temperature, 0.6 °C in surface temperature, and 7% less ice coverage between them. Comparison of centre of gravity, inertia, and spatial overlap of the modelled and surveyed spatial distributions in warm and cold years showed that the model represented the past distributions of the functional groups satisfactorily. We observed poleward shifts of 41 and 68 km for the modelled and observed distributions, respectively, in the average centre of gravity position for the 35 FGs with lowest sampling uncertainty. The model predicted that the whole community had shifted distribution towards the northeast at an average rate of 4.4 km year−1 and 67 km °C-1 between 2004 and 2013. We conclude that our Ecospace model represents past observed species distributions in the Barents Sea satisfactorily, and may predict the direction and magnitude of temperature-driven changes in spatial distributions. This ability may be useful for predicting the impact of climate changes on species and FG distributions in future scenarios.

Applying the Safe Operating Space (SOS) Approach to Sustainable Commercial Fishing under Varying Lake Levels and Littoral Zone Conditions

Successful management of lake ecosystems and the ecosystem services they provide necessitates ecosystem‐based management. The application of ecosystem‐based management can assist in achieving sustainable management of the ecosystem to ensure continued and sustainable supply of ecosystem services such as fisheries. One concept for defining sustainable fishing is the Safe Operating Space (SOS). In our study, we apply the Ecopath with Ecosim suite of models to predict the SOS required for the management of a commercial fishery. We use the Lake Kinneret (Israel) ecosystem as a case study to illustrate the approach by developing an Ecospace model of the lake and incorporating the spatio‐temporal framework and varying environmental conditions. We test, and demonstrate, the methodology for developing a SOS for a commercial fish population that can be implemented by lake managers elsewhere and illustrate it's use by defining example target values of biomass (e.g., 200 and 250 tons) and catch (e.g., 125 tons/year). Our results show that the SOS for a given target can be defined by a range of fishing efforts and vegetation cover in the lake as a function of lake level. The complexity in defining the actual values highlight the benefit of the approach we present here.

Modeling Small Scale Impacts of Multi-Purpose Platforms: An Ecosystem Approach

Aquaculture and marine renewable energy are two expanding sectors of the Blue Economy in Europe. Assessing the long-term environmental impacts in terms of eutrophication and noise is a priority for both the EU Water Framework Directive and the Marine Strategy Framework Directive, and cumulative impacts will be important for the Maritime Spatial Planning under the Integrated Maritime Policy. With the constant expansion of aquaculture production, it is expected that farms might be established further offshore in more remote areas, as high-energy conditions offer an opportunity to generate more power locally using Marine Renewable Energy (MRE) devices. A proposed solution is the co-location of MRE devices and aquaculture systems using Multi-Purpose Platforms (MPPs) comprising offshore wind turbines (OWTs) that will provide energy for farm operations as well as potentially shelter the farm. Disentangling the impacts, conflicts and synergies of MPP elements on the surrounding marine ecosystem is challenging. Here we created a high-resolution spatiotemporal Ecospace model of the West of Scotland, in order to assess impacts of a simple MPP configuration on the surrounding ecosystem and how these impacts can cascade through the food web. The model evaluated the following specific ecosystem responses: (i) top-down control pathways due to distribution changes among top-predators (harbor porpoise, gadoids and seabirds) driven by attraction to the farming sites and/or repulsion/killing due to OWT operations; (ii) bottom-up control pathways due to salmon farm activity providing increasing benthic enrichment predicated by a fish farm particle dispersal model, and sediment nutrient fluxes to the water column by early diagenesis of organic matter (recycled production). Weak responses of the food-web were found for top-down changes, whilst the results showed high sensitivity to increasing changes of bottom-up drivers that cascaded through the food-web from primary producers and detritus to pelagic and benthic consumers, respectively. We assessed the sensitivity of the model to each of these impacts and the cumulative effects on the ecosystem, discuss the capabilities and limitations of the Ecospace modeling approach as a potential tool for marine spatial planning and the impact that these results could have for the Blue Economy and the EU’s New Green Deal.

Palaeoecological patterns of change in marine invertebrate faunas across the End-Triassic mass extinction event: Evidence from Larne, Northern Ireland

The End-Triassic mass extinction event [ETE] (201.5 Ma) marks a drastic turnover and loss of >50% of marine biodiversity. Suggested environmental factors include extreme climate change and global carbon-cycle perturbations linked to Central Atlantic Magmatic Province (CAMP) volcanism. Considerable attention has been paid to disentangling the causes and selectivity of the ETE, whilst downplaying the patterns of change in the structure and functioning of marine paleofauna. Here we provide detailed quantitative information from across the Triassic-Jurassic boundary at Waterloo Bay, Larne, Northern Ireland, to describe patterns of changes in different palaeoecological parameters across the ETE. The analysis was based on abundance data of species sampled from approximately 1 m intervals through the sequence. Dominance and richness were estimated using rarefaction techniques and β-diversity index, and distinctness diversity indices were calculated. Changes in species composition were evaluated by multivariate analysis (nMDS, ANOMSIM and SIMPER). Rank abundance models were fitted, and functional diversity were estimated based on an ecospace model, applied to each sampled unit to detect changes in structure and ecological complexity. Across the ETE three distinctive states were identified: the pre-extinction state (Westbury Formation), characterised by an assemblage with high species richness and ecological redundancy, and with low taxonomic variation and functional diversity. The extinction state (Cotham and Langport members) represents a shift of the marine ecosystem, where >70% marine species disappears decreasing the ecosystems functioning the marine ecosystem around 80%. The recovery state (Lias Group), commencing some ~150 ky after the extinction, with ecologically complex assemblages as new taxa colonised, increasing variation in taxonomic distinctness and new contributing ecological traits and functional richness through the Hettangian. The palaeoecological patterns described here are robust enough to discount possible facies effects, but more important, is consistent with other studies reported globally, and demonstrates that the ecological signals detected in this study are real.

The Celtic Sea Through Time and Space: Ecosystem Modeling to Unravel Fishing and Climate Change Impacts on Food-Web Structure and Dynamics

Both trophic structure and biomass flow within marine food webs are influenced by the abiotic environment and anthropogenic stressors such as fishing. The abiotic environment has a large effect on species spatial distribution patterns and productivity and, consequently, spatial co-occurrence between predators and prey, while fishing alters species abundances and food-web structure. In order to disentangle the impacts of the abiotic environment and fishing in the Celtic Sea ecosystem, we developed a spatio-temporal trophic model, specifically an Ecopath with Ecosim with Ecospace model, for the period 1985–2016. In this model, particular attention was paid to the parameterization of the responses of all trophic levels to abiotic environmental changes. Satellite remote sensing data were employed to determine the spatial distribution and annual fluctuations of primary production (PP). Spatial and temporal changes in the habitat favorable for zooplankton were predicted with a novel ecological-niche approach using daily detection of productivity fronts from satellite ocean color. Finally, functional responses characterizing the effect of several abiotic environmental variables (including, among others, temperature, salinity and dissolved oxygen concentration, both at the surface and at the bottom) on fish species groups’ habitat suitability were produced from the predictions of statistical habitat models fitted to presence-absence data collected by multiple fisheries-independent surveys. The dynamic component of our model (Ecosim) was driven by time-series of fishing effort, PP, zooplankton habitat suitability and abiotic environmental variables, and was fitted to abundance and fisheries catch data. The spatial component of our model (Ecospace) was constructed, for specific years of the period 1985–2016 with contrasted abiotic environmental conditions, to predict the variable distribution of the biomass of all functional groups. We found that fishing was the main driver of observed ecosystem changes in the Celtic Sea over the period 1985–2016. However, the integration of the environmental variability into the model and the subsequent improvement of the fit of the dynamic Ecosim component highlighted (i) the control of the overall pelagic production by PP and (ii) the influence of temperature on the productivity of several trophic levels in the Celtic Sea, especially on trophic groups with warm and cold water affinities. In addition, Ecospace predictions indicated that the spatial distributions of commercial fish species may have substantially changed over the studied period. These spatial changes mainly appeared to be driven by temperature and may, therefore, largely impact future fisheries given the continuity of climatic changes.

A spatial food web model to investigate potential spillover effects of a fishery closure in an offshore wind farm

There is a growing interest in the development of offshore wind farms to provide a sustainable source of renewable energy and contribute to the reduction of carbon emissions. In parallel, there is a need to better understand the effects of these installations on coastal marine ecosystems and identify potential sea use conflicts, especially when the area is subject to access restrictions. This study investigated the effects of a spatial closure during the exploitation phase of an offshore wind farm in the extended Bay of Seine (English Channel, France) using Ecospace, a spatially and temporally explicit module of Ecopath with Ecosim. To address this question, simulations were conducted through the evaluation of “what-if scenarios” to assess the effectiveness of a fishing exclusion zone inside and surrounding the offshore wind farm. Several biomass, catch and trophic level-based indicators were calculated to evaluate how the exclusion zone could affect fishing activities and main components of the food web. All the indicators were estimated in the extended Bay of Seine and summarized by sub-area. Findings suggested that the spillover effect could mitigate the negative impact of access loss on fishing activities, in a scenario of simulated closure of the area of the wind farm. The Ecospace model predicted an increase of catches (up to 7% near the wind farm) and a slight increase in the proportion of high trophic level species. However, the influence of spillover effects is limited in space and the expected increase of biomass and catches are highly localized in areas around the offshore wind farm installations. At the scale of the Bay of Seine, further analysis of the spillover effects revealed a spatial pattern and suggested that the implementation of an exclusion zone inside the offshore wind farm could concentrate highly mobile predators.

How long-term water level changes influence the spatial distribution of fish and other functional groups in a large shallow lake

We numerically explored the effects of long-term water level changes on biotic biomass and spatial distribution of fish in a large shallow lake. We calibrated Ecospace model (Ecopath with Ecosim modelling suite) with data from various functional groups (ranging from phytoplankton to piscivorous fish), and considered 14 different habitats. Two scenarios representing, respectively, a long-term water-level increase and decrease by 1 m were constructed and run for a period of thirty eight years (1979–2016). The results showed a very uneven spatial distribution of fish biomass in the lake, with the highest concentration in the southern basin. The 1 m decrease scenario caused a diminution in the biomass of all groups but piscivorous fish. The 1 m increase scenario saw a weak decrease in most species biomass. Consequently, in both scenarios, long-term water level changes would be generally detrimental to the lake biota. In the context of more frequent climate-induced hydrological fluctuations, we encourage the use of these simulations as effective tools for future prediction and assessment of ecosystem-based fisheries management and ecological status maintenance of shallow lakes.

Representing species distributions in spatially-explicit ecosystem models from presence-only data

Spatially-explicit ecosystem models are increasingly considered for informing fisheries management. The inputs of these models that determine species distributions in the modeled system are critical. There is a need for methods to estimate species distributions in spatially-explicit ecosystem models from presence-only data. To address this need, we used a method relying on binomial generalized additive models integrating environmental covariates. This method allows for the production of distribution maps for ecosystem models such as Atlantis models, and of preference functions for Ecospace models; preference functions define the preferences of species groups for certain environmental parameter values and are employed by Ecospace to allocate species group biomasses spatially. The key step of the method we used is the objective generation of pseudo-absences for each month, by sampling with replacement the centroids of the cells of fine-scale spatial grids defined for each month. To demonstrate the method, we applied it to the diving bird and surface-feeding bird groups represented in the Atlantis model for the Gulf of Mexico (GOM), and to the seabird group represented in the Ecospace model for the West Florida Shelf. We also employed the distribution maps we constructed to provide a basis for a hypothetical marine protected area (MPA) planning scenario aiming to secure food for seabirds. Specifically, we produced a hotspot map for seabirds for the U.S. GOM from the distribution map of the species group, and then combined the hotspot map for seabirds with a hotspot map for their main prey, forage fish (Clupeidae and Exocoetidae), to determine where the hotspots of seabirds and forage fish overlap. This analysis suggested that, to secure forage fish for seabirds in the U.S. GOM, hypothetical MPAs should be implemented primarily within the coastal regions of the Louisiana-Texas shelf, within the coastal region of West Florida located between Sarasota and Naples and/or within Apalachee Bay, Florida.

Assisting Ecosystem‐Based Fisheries Management Efforts Using a Comprehensive Survey Database, a Large Environmental Database, and Generalized Additive Models

AbstractStatistical habitat models, such as generalized additive models (GAMs), are key tools for assisting ecosystem‐based fisheries management (EBFM) efforts. Predictions from GAMs can be used, for example, to produce preference functions for the ecosystem‐modeling platform Ecospace; preference functions permit a flexible representation of spatial distribution patterns in Ecospace by defining the preferences of marine organisms for certain environmental parameter values. Generalized additive model predictions can also be used to map species distributions for assisting marine protected area (MPA) planning. In this study, we applied a recently proposed methodology to produce preference functions for the fish and invertebrates represented in an Ecospace model of the West Florida Shelf (WFS) and to map the hotspots of juveniles and adults of three economically important species for informing future MPA planning in the WFS region. This proposed methodology consists of (1) compiling a comprehensive survey database blending all of the encounter and nonencounter data of the study ecosystem collected by the fisheries‐independent and fisheries‐dependent surveys that employ random sampling schemes, (2) developing a large environmental database to store all of the environmental parameters influencing the spatial distribution patterns of the marine organisms of the study ecosystem, (3) using the comprehensive survey database and the large environmental database to fit binomial GAMs that integrate the confounding effects of survey and year, and (4) making predictions with fitted GAMs to define preference functions for marine organisms and produce distribution and hotspot maps. All the GAMs we fitted were able to predict probabilities of encounter with reasonable or excellent discrimination and had a median adjusted coefficient of determination larger than the 0.1 threshold required for validation. The preference functions and hotspot maps produced using the fitted GAMs were generally in concordance with the literature. The methodology demonstrated in this study is timely, given the increasing interest in advancing EBFM worldwide.

Early evolutionary diversification of mandible morphology in the New World monkeys (Primate, Platyrrhini)

New World monkeys (order Primates) are an example of a major mammalian evolutionary radiation in the Americas, with a contentious fossil record. There is evidence of an early platyrrhine occupation of this continent by the Eocene–Oligocene transition, evolving in isolation from the Old World primates from then on, and developing extensive morphological and size variation. Previous studies postulated that the platyrrhine clade arose as a local version of the Simpsonian ecospace model, with an early phase involving a rapid increase in morphological and ecological diversity driven by selection and ecological opportunity, followed by a diversification rate that slowed due to niche-filling. Under this model, variation in extant platyrrhines, in particular anatomical complexes, may resemble patterns seen among middle–late Miocene (10–14 Ma) platyrrhines as a result of evolutionary stasis. Here we examine the mandible in this regard, which may be informative about the dietary and phylogenetic history of the New World monkeys. Specifically, we test the hypothesis that the Simpsonian ecospace model applies to the platyrrhine mandible through a geometric morphometric analysis of digital images of the jaws of extant and extinct species, and we compare these results to those obtained using a phylogenetic comparative approach based on extant species. The results show a marked phylogenetic structure in the mandibular morphology of platyrrhines. Principal component analyses highlight the morphological diversity among modern forms, and reveal a similar range of variation for the clade when fossil specimens are included. Disparity-Through-Time analysis shows that most of the shape variation between platyrrhines originated early in their evolution (between 20 and 15 Ma). Our results converge with previous studies of body mass, cranial shape, the brain and the basicranium to show that platyrrhine evolution might have been shaped by an early increase in morphological variation followed by a decelerated rate of diversification and evolutionary stasis.

A spatio-temporal ecosystem model to simulate fishing management plans: A case of study in the Gulf of Gabes (Tunisia)

The Gulf of Gabes located in southern Tunisia is one of the most productive ecosystems in the Mediterranean Sea. Despite its ecological importance, it is subject to high fishing pressure affecting the different components of the ecosystem. Given the multispecies, multigear nature of the fishery, there is a need to manage trade-offs between environmental and economic objectives. In this study, an Ecospace model was developed based on the previously constructed Ecopath model of the Gulf of Gabes and calibrated for the period 1995–2008 to investigate the response of the ecosystem to a set of alternative spatial management scenarios. These scenarios were derived from the current fishery regulation owing the important interest expressed by local fishery managers to assess new management measures. The results showed for each management scenario how bottom trawling and coastal fishing impact the different trophic groups and the complexity of interaction between these two fishing activities. Furthermore, spatially explicit simulations were performed to identify regions where the management measures are effective. Results suggested that for some trophic groups, these regions are well-defined which would be interesting to propose more accurate spatial measures. Finally, several indicators were calculated to evaluate the proposed management plans and provide managers with a straightforward set of decision rules to describe the potential trade-offs and fulfill both fisheries and conservation management objectives in the context of an ecosystem approach. The decision rules were based on observed trends to reduce uncertainty relative to the model complexity and provide consistent advice to decision-makers.

Exploring the potential effects of marine protected areas on the ecosystem structure of the Gulf of Gabes using the Ecospace model

The Gulf of Gabes is considered as one of the most productive areas of the southern Mediterranean Sea and it plays an important role in Tunisian economy. It is known to be an archetypal ecosystem in which the effects of fisheries are the most pronounced. Based on the stock assessment outcomes, it is as a highly exploited ecosystem. Thereupon, it becomes necessary to establish adequate measures to facilitate the recovery of the marine resources. The most important sets of management measures regard the establishment of Marine Protected Areas (MPAs). However, these management plans should be assessed beforehand to make sure of the relevance of the measure and its impact on marine resources. Modeling may significantly enhance our understanding of the likely impacts of fisheries management plans on groups that are very difficult to study and this approach gives insights at larger spatial scales. We used Ecospace to investigate the potential impacts of several spatial management plans on the ecosystem structure of the Gulf of Gabes. The Ecospace model is based on the existing Ecopath model elaborated by Hattab (2013). The simulation were carried over a 15-year period. The outcomes of the simulations, suggest that the implementation of MPAs in the Gulf of Gabes could be simultaneously beneficial for the ecosystem and fishing activities. However, the benefits are related to the characteristics of the MPA. The spatial simulations highlight that the location is crucial to the success of the MPA. Additionally, an increase in the size of a MPA can result in an increase in the spillover effect and, consequently, in catches in the neighborhood without harming ecosystem integrity. The configuration of the implemented MPA is of capital importance, a set of many small MPAs is more beneficial than fewer and larger MPAs, especially in terms of catches.

Spatial ecosystem modelling of marine renewable energy installations: Gauging the utility of Ecospace

The deployment of offshore structures for renewable energy generation (wind/wave/tidal) will lead to the alteration of access to the area of installation for several users of the sea including: shipping, fishing, tourism and recreational users. Arguably, the largest impact will be upon the fishing industry where access loss may lead to displacement and reduced catch per unit effort in turn leading to conflict. To prevent conflict, it is important to understand mitigating factors. Marine renewable energy devices (MREDs) and associated infrastructure will be placed on the seabed, affecting benthic infauna and epifauna, important sources of food for many species including those of commercial importance, potentially providing benefits to the fishing industry and mitigating the causes of conflict. Two key plausible benefits of MREDs are the ‘artificial reef effect’ and the ‘exclusion zone effect’. This study investigated the utility of the Ecopath with Ecosim and Ecospace modelling software to address the implications of these ‘effects’. Two case study models were developed, one at the whole west coast of Scotland shelf scale and one at a smaller single installation scale. Our results suggested that the Ecospace model could potentially predict the effects of MRED installations, but revealed that there are a number of considerations which should be taken into account before attempting to do this. Key considerations include data availability (an issue in all modelling), spatial scale and resolution. Other limitations to this particular study such as the ability to make changes over time are currently being addressed by ongoing developments of the software. Despite the considerations and limitations, these case studies reveal the usefulness of spatial ecosystem modelling, particularly Ecospace, to investigate this issue.

Exploring effects of hypoxia on fish and fisheries in the northern Gulf of Mexico using a dynamic spatially explicit ecosystem model

The formation of an extensive hypoxic area off the Louisiana coast has been well publicized. However, determining the effects of this hypoxic zone on fish and fisheries has proven to be more difficult. The dual effect of nutrient loading on secondary production (positive effects of bottom-up fueling, and negative effects of reduced oxygen levels) impedes the quantification of hypoxia effects on fish and fisheries. The objective of this study was to develop an ecosystem model that is able to separate the two effects, and to evaluate net effects of hypoxia on fish biomass and fisheries landings. An Ecospace model was developed using Ecopath with Ecosim software with an added plug-in to include spatially and temporally dynamic Chlorophyll a (Chl a) and dissolved oxygen (DO) values derived from a coupled physical–biological hypoxia model. Effects of hypoxia were determined by simulating scenarios with DO and Chl a included separately and combined, and a scenario without fish response to Chl a or DO. Fishing fleets were included in the model as well; fleets move to cells with highest revenue following a gravitational model. Results of this model suggest that the increases in total fish biomass and fisheries landings as a result of an increase in primary production outweigh the decreases as a result of hypoxic conditions. However, the results also demonstrated that responses were species-specific, and some species such as red snapper (Lutjanus campechanus) did suffer a net loss in biomass. Scenario-analyses with this model could be used to determine the optimal nutrient load reduction from a fisheries perspective.

The Ecospace model applied to the North Sea: Evaluating spatial predictions with fish biomass and fishing effort data

The Ecospace model has been developed from the Ecopath with Ecosim food web model to add a spatial dimension for investigating marine ecosystems. In this study, we evaluated the sensitivity of an Ecospace model developed for the North Sea ecosystem to some of its key parameters, and we examined this model's capability to reproduce trends in spatial time-series of fish biomass and fishing effort. We measured the fit between the spatiotemporal model predictions and the corresponding data of biomass for 12 species and effort for three fishing fleets. Our results suggest that the Ecospace model for the North Sea can predict quite successfully the species distribution, but not the distribution of fishing effort. We hypothesise that the reason might be that Ecospace assumes spatial effort distribution to be driven mainly by profit, while other factors might be more important in our system at the spatiotemporal scale explored. The model might thus fail to capture fisher's behaviour accurately for this system. Despite the limitations of our ad hoc approach for sensitivity analysis, these results hint that some problems exist in our model, which might extend to other Ecospace models and perhaps to the framework in general. This study highlights the importance of validating Ecospace models with data if their results are used for management advice. We suggest that, in order to make of Ecospace a more robust tool for management advice, some critical improvements are needed: the development of an algorithm for parameter optimisation through fitting the model predictions to data, and advancement of the effort distribution model.

Evaluation of the effects on rockfish and kelp artisanal fisheries of the proposed Mejillones Peninsula marine protected area (northern Chile, SE Pacific coast)

•One shortcoming of marine protected areas (MPA) implementation is the potential for unintended consequences, such as fisheries effort displacement, that cause negative economic and social effects for fishermen and undermine social support for MPA implementation efforts.•The objective of this work is to analyse the effects of a proposed MPA system on fisheries in a biodiversity conservation priority site in northern Chile using a spatial dynamic modelling approach and incorporating ecological, social and economic criteria.•We developed an Ecospace model representing the ecological benthic subsystems dominated by kelp beds off the Mejillones Peninsula, Chile. We compared changes in fisheries indicators and the spatial distribution of effort among a no-MPA baseline scenario and four scenarios using proposed MPA core and buffer zones with high or low dispersal rates for the species in the model.•An overlay analysis was performed to identify which zones and users of the fishing grounds would be affected by the proposed MPA system and to what degree.•We found a high degree of overlap of the proposed MPA site with fishing grounds of high economic importance and with a fishing ground where women are allowed to work, this can cause significant displacement of women that have no alternative livelihood, with possible undesired social impacts on the fishing community.•Results from the kelp forest spatial food web model reveals that the biomass build-up of fished species is sensitive to dispersal rates, especially in scenarios with small reserves. A general pattern of fishing effort reallocation at the border of individual MPAs and open areas closer to the port was observed. Fisheries indicators show negative effects for both MPA scenarios, with undesirable changes in catch and profits for rockfish and kelp exploitation.•Our results suggest that implementation of the MPA proposal for the Mejillones Peninsula could generate negative consequences for the fishing community of Constitución cove. The inclusion of fisheries management objectives along with biodiversity conservation in the planning process of the Mejillones Peninsula MPA system may help to address putative negative effects on fisheries and may allow for the creation of support for future MPAs from the fishermen community.

Exploring the effects of spatial closures in a temperate marine ecosystem in Western Australia: A case study of the western rock lobster (Panulirus cygnus) fishery

An Ecospace model, was developed to investigate the potential impacts of spatial closures on key species and the food webs in the Jurien Bay Marine Park (JBMP), central Western Australia (823km2). The model comprised 80 functional groups (more than 200 species). The JBMP is a multiple use-marine park with several types of zoning and the effects of these on rock lobster biomass, mortalities and landings were explored using five Ecospace scenarios as baselines: (1) no-take Sanctuary Zones covering 4% of the total area; area of Sanctuary Zones changed to (2) 25%, (3) 50%; (4) 0%, i.e. No Sanctuary Zones; and (5) combining 25% of no-take areas with a 50% reduction in fishing mortality of the main targeted species. The results suggest that the introduction of the current management zones with 4% of the area in Sanctuary Zones produced a modest increase of ∼5% in the biomass of western rock lobster after 20 years, even with stable fishing effort. However, Western Rock Lobster biomass increased by ∼20% when the Sanctuary Zones covered 25% of the Park. Similar trends were observed for exploited fish species such as pink snapper, dhufish, and small sharks with their biomasses predicted to increase by up to 30% as the area of sanctuary zones increase from 4% to 50%. The largest predicted increases in biomass for the main target species were found when the protection from the sanctuaries (25%) was combined with a 50% reduction of fishing pressure. The catch of finfish species improved up to 70% (e.g. pink snapper) when a 25% of no-take area simulated was combined with a 50% reduction of fishing mortality during 20 years. To test the effects of habitat structure on the effectiveness of these fishing closures, a set of four scenarios were developed. We relocated the current 4% of sanctuaries, which are mainly associated with a reef-seagrass habitat, to the other three major habitats (reefs, seagrass and sand). The predicted fish biomass was higher when sanctuaries were placed on high structured habitats, such as reefs and seagrass-reefs (10–90%) than seagrass and sandy areas.

Spatial and mass balanced trophic models of La Rinconada Marine Reserve (SE Pacific coast), a protected benthic ecosystem: Management strategy assessment

Steady-state, dynamic, and spatial models were constructed for the benthic system of La Rinconada Marine Reserve off northern Chile (SE Pacific coast). We examined data on biomass, P/B ratios, catches, food spectrum, consumption, and the dynamics of commercial and non-commercial populations using three theoretical frameworks: Ecopath, Ecosim, and Ecospace. The biomass of the scallop Argopecten purpuratus and the clam Tagelus dombeii were the most relevant compartments of the studied ecosystem. Among the carnivores, the functional crab group Cancer spp. was the most relevant. The Rhodophyta was the dominant macroalga compartment of the system. The results obtained using mixed trophic impacts (MTI) showed that the predatory snail Thais chocolata propagated higher magnitudes of direct and indirect effects on the other species or functional groups. The sea star Luidia magallanica and Rhodophyta had the least effects on the remaining compartments. According to the Ecosim estimates (increasing mortality by fishing), the scallop A. purpuratus had the highest impact on the other compartments. The Ecospace model showed similar qualitative and quantitative effects for changes in biomass under three different exploitation scenarios (by subsystems and globally). Nevertheless, the greatest changes were provoked by using the top-down control and the vulnerabilities estimated by Ecosim. System recovery times were highest with increased mortality of the asteroid L. magallanica and the carnivorous snail T. chocolata, suggesting that the sea star could be considered to be a top predator with a top-down control. The F MSY estimated for the scallop A. purpuratus was close to the F i originally entered in Ecopath, limiting the design and execution of an exploitation plan within ecologically sustainable boundaries. The situation was different ( F MSY ≪ F i ) for the other commercial species, making possible multi-species exploitation programs. The Ecospace trophic-spatially explicit model shows a similar pattern of direct and indirect effects generated when exerting exploitation separately by subsystems. Therefore, habitat rotation of fisheries is not justified.