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Follow on to the development of spatial models of essential fish habitat for the South Inshore and Offshore Marine Plan Areas

Franco, Anita; Shona, Thomson


Anita Franco

Thomson Shona


The ability to spatially locate resources in the marine environment with confidence and at high resolution is central to marine planning and required to manage anthropogenic activities for a sustainable integrated use of the sea. Essential fish habitats are important resources due to their high ecological value in supporting critical fish life stages and their social and economic value as highlighted by ecosystem service models. As such, essential fish habitat maps may represent important supporting tools for the development of marine plan policies in England. The lack of high resolution data on essential fish habitats constitutes a major limitation for the reliable identification of high value habitats and their practical consideration in the marine planning process. To address this problem, a project (MMO (2013)) was undertaken in 2013 to improve the spatial resolution of data on essential fish habitat for fish species of commercial and / or ecological relevance in the South Inshore and South Offshore Marine Plan Areas (hereafter referred to as the South marine plan areas). MMO (2013) used empirical geospatial modelling (classification tree models) of fish survey and environmental data to generate spatial predictions of the presence of fish life stages for ten fish species in the South marine plan areas. MMO (2013) also developed a methodology to assess the confidence associated with model outputs, by combining confidence assessments on the input data and the statistical model predictive ability. The project spatial outputs therefore included maps of the predicted distribution of essential fish habitats (nursery, spawning and adult foraging rounds)
for individual species with associated confidence value and onfidence maps. MMO (2013) also developed an integrative approach to combine these maps into multispecies hot spot maps (with associated confidence) identifying areas of higher ecological value based on the frequency of occurrence of the essential habitats for different species. The outputs of MMO (2013) were heavily influenced by the availability and quality of source data and scientific evidence to support the modelling logic as well as the time available to collate and prepare the data. Stakeholder consultation and model validation were recommended to improve the confidence assessment of the MMO (2013) spatial outputs. The present project follows up on this recommendation with the aim of understanding whether the MMO (2013) spatial outputs can be used to support the development of marine plan policies in England. The present project used a stakeholder consultation and validation activity to fulfil the following objectives: 1) validating the essential fish habitat maps developed in MMO (2013) against new data and expert judgement; 2) identifying additional data to improve the confidence in the MMO (2013) essential fish habitat predictions and for the application of the approach in other marine plan areas; 3) obtaining the consultees’ view on the acceptability of the MMO (2013) approach as a tool to support marine planning in England; and 4) providing recommendations to make the model as robust as possible, run the model for all marine plan areas and ensure it can be used in development of marine plans for England. The consultation engaged the Department for Environment, Food & Rural Affairs (Defra), the Centre for Environment, Fisheries and Aquaculture Science (Cefas), the Joint Nature Conservation Committee (JNCC) and Natural England, as well as other organisations within the UK such as Marine Scotland Science, Natural Resources Wales, Department of the Environment Northern Ireland, Agri-Food and Biosciences Institute Northern Ireland and the Inshore Fisheries and Conservation Authorities (IFCAs) within or adjacent to the South marine plan areas. A questionnaire and discussion via web conferencing were employed. Consultees were asked to provide their view on the validity of the MMO (2013) approach and to identify areas of mismatch between the MMO (2013) spatial predictions of essential fish habitats and their expert knowledge. This information was used to identify areas of reduced confidence in the MMO (2013) maps. The confidence assessment of the MMO (2013) spatial outputs was also improved by statistically validating the model predictions against independent fish survey data. This allowed the re-evaluation of the model predictive ability hence the amendment of the overall confidence associated with the MMO (2013) spatial outputs. Additional data from fish surveys or environmental data layers were also identified based on the consultees’ suggestions and on further input from the Institute of Estuarine and Coastal Studies (IECS). The associated metadata were explored in order to assess the suitability of these data to improve the MMO (2013) models and/or to allow the application of the approach to other marine plan areas. Due to the limited time available, Defra’s acceptance of the MMO (2013) approach relied on MMO and Cefas judgement and the fishery research scientist consulted in Cefas could not provide an organisation level acceptance of the suitability of the method for marine planning. Although a formal agreement has not yet been obtained, discussion with Cefas, Defra and other organisations allowed identification of strengths and weaknesses associated with the MMO (2013) approach. It was therefore possible to formulate a series of recommendations to improve the approach.
The validation activity confirmed that confidence issues were mostly associated with input data layers used to obtain spatial predictions rather than model predictive ability. There was a good agreement of the accuracy of the maps with the expert knowledge and additional empirical evidence, and the statistical validation often led to an increase in the overall confidence in the spatial outputs. The importance of using expert knowledge in addition to statistical validation to refine the model outputs was highlighted during consultation and therefore it was recommended that this is
included as a procedure within the MMO (2013) approach.
The confidence improvement was evident in particular for maps of nursery habitats based on the prediction of occurrence of fish juvenile stages. In most cases these maps reached a moderate confidence after validation. Such an improvement suggests that these maps may have increased utility as spatial areas for marine planning to use in policy formulation. Further improvements of these outputs could be obtained by replacing or integrating the environmental variables used in the models with additional environmental data layers with higher confidence which were not available in this study, as suggested during consultation. This represents a further step towards the improvement of the robustness of the models and the use of the resulting spatial outputs in marine planning. A higher uncertainty was associated with the spatial prediction of spawning and adult feeding grounds relative to nursery areas and amendments to the models were identified as ways of making the models more robust and improving the confidence in their predictions. For example, the inclusion of abundance data of pelagic eggs and larvae in combination with the presence / absence data used in the current models was recommended.
The exploration of additional data allowed identification of environmental data layers that should be used as new, additional parameters in the MMO (2013) models. These include variables obtained from detailed energy data layers, Terrain Ruggedness Index obtained from bathymetric data layers and chlorophyll concentration. The use of these additional environmental data has the potential to improve the prediction and confidence in the model outputs in the South marine plan areas and also in other marine plan areas, hence increasing their suitability as supporting tools for marine planning.
During consultation, the limited coverage of species included in MMO (2013) was identified as an important limitation of the approach, particularly when an integrative assessment of the ecological value is undertaken by combining the information obtained from maps of essential fish habitats of individual species (as with hot spot maps). Additional fish survey data from datasets used in MMO (2013) and from additional datasets were identified as useful to increase the species coverage in the South marine plan areas (e.g. with inclusion of turbot, brill, whiting and cod) and expand the approach application to other marine plan areas. Notwithstanding the availability of additional fish survey data, not all data are suitable for modelling according to data requirements specified in MMO (2013) (e.g. wide spatial coverage of a fish survey dataset in the marine plan area). A
reduced spatial coverage of suitable fish survey data in inshore areas was also identified in MMO (2013) and confirmed in this project, hence limiting the applicability of the models in these areas. The integration of the MMO (2013) spatial outputs with information from other sources better covering these areas (e.g. EA assessments of fish distribution inshore) was therefore recommended. Considering that the above limitations could possibly lead to an underestimation of the overall ecological value of an area, the use of expert knowledge to validate hot spot maps was recommended.
Although a formal agreement could not be obtained within the timeline of this project, discussions are still ongoing within Cefas to provide the organisation’s view on the MMO (2013) method. The confidence improvement that would likely result from addressing the recommendations above is considered an important factor that would further increase the suitability of the spatial outputs as supporting tools for the development of marine plan policies in England.


Franco, A., & Shona, T. (2016). Follow on to the development of spatial models of essential fish habitat for the South Inshore and Offshore Marine Plan Areas. Marine Management Organisation

Report Type Project Report
Publication Date Mar 1, 2016
Deposit Date May 22, 2018
Publicly Available Date Jun 14, 2018
Pages 142
Series ISSN ISBN: 978-1- 909452-40-4
Public URL
Publisher URL
Additional Information This report should be cited as:
MMO (2016). Follow on to the Development of Spatial Models of Essential Fish Habitat for the South Inshore and Offshore Marine Plan Areas. A report produced for the Marine Management Organisation, pp 142. MMO Project No: 1096. ISBN: 978-1-909452-40-4.


Report (14 Mb)

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