Fish and fisheries research to inform ScotMER evidence gaps and future strategic research in the UK: review

Evidence Gap FF.01: Accurate mapping of fishing effort and catches in space and time

Review of current knowledge

Commercial fisheries impact assessments are generally informed by the undertaking of desktop reviews of existing studies and datasets and complemented with the collection of data and information on fishing activities through direct consultation with fisheries stakeholders.

Standard fisheries data sources that are frequently used to characterise fishing activities spatially and temporally in UK waters include the following:

• Landings and Effort Statistics: These are primarily based on landings declarations and logbook data. To allow the identification of the broad sea areas where fish and shellfish have been caught, landings and effort data used to inform commercial fisheries assessments are generally analysed by International Council for the Exploration of the Sea (ICES) rectangle, the smallest spatial unit used in the collection of this type of data.
• Vessel Monitoring System (VMS) Data: VMS data are derived from position information reported by UK and EU Member States' vessels carrying the EU mandated monitoring system. Since 2012 all commercial fishing vessels of 12 metres and over in length have been required to report their position, course and speed at regular intervals using VMS. Prior to 2012 this requirement only applied to commercial fishing vessels of 15 metres and over.

Fishing is not equally distributed across the area of ICES rectangles, hence, the overall landings and effort data recorded for a given rectangle may not be representative of the activity which occurs across different subsections of the rectangle. Whilst VMS data provides information at increased spatial resolution, in its raw format it does not provide quantitative information in respect of aspects such as catch weight, value and effort. In addition, this data does not identify whether vessels are actively fishing or simply in transit. Over the last ten years, however, data analysis methodologies have been developed to improve the characterisation of fishing activity using VMS data (i.e. Lee et al 2010, Gerritsen et al 2011, Bastardie et al 2010). In addition, the establishment of the ICES Working Group on Spatial Fisheries Data (WGSFD) has facilitated the implementation of standardised methods for the analysis of VMS data across countries.

At present, the combination of VMS data with logbook information is considered the most practical and cost-effective way to describe the spatial dynamics of fishing activities (ICES 2019). In the UK, data in this format is collated for UK registered vessels by aggregating the number of position plots by gear type in a 0.05 x 0.05 degree grid. This is then combined with landings values to provide effort, value (£) and weight (tonnes) outputs for each cell within the grid. The data is filtered by speed so that only activity of vessels deemed to be fishing is included in the dataset. It should be noted, however, that VMS combined with logbook data is provided separately by fishing method and in some cases a single method may encompass vessels from different fleet segments. For instance, data for bottom otter trawls amalgamates information from vessels engaged in squid, Nephrops and whitefish fisheries, whilst the beam trawl category would mostly include activity of Anglo-Dutch and UK beam trawlers targeting flatfish as well as vessels engaged in the shrimp fishery. This, together with the need to anonymise vessels in the dataset due to confidentiality issues means that the extent and level of activity of vessels engaged in a particular fishery may not always be accurately represented by this data. Approaches which allow the mapping of activity by fleet segment or fishery should be favoured where feasible (i.e. see Kafas et al 2013). In addition, as VMS data is currently only available for vessels of 12 metres and over, this type of data does not take account of fishing activity undertaken by vessels in the smaller length categories. Vessels under 12 metres in length tend to account for the majority of fishing in areas close to shore, therefore, VMS-based datasets provide little information of fishing activity in inshore waters.

The lack of accurate spatial data to describe fishing activity in inshore areas has resulted in various studies being commissioned in recent years to address this information gap. These have generally involved participatory mapping methods to spatially identify fishing grounds. Examples of these include:

• "FisherMap": The FisherMap study aimed to map the extent and intensity of fishing activities around the English coast to inform new Marine Conservation Zones (MCZs) recommendations under the UK's Marine and Coastal Access Act. Data were collected by interviewing 1,914 fishermen by four regional project teams across England ("Net Gain", "Balanced Seas", "Finding Sanctuary" and "Irish Sea Conservation Zone") undertaken between 2007 and 2010 (Enever et al 2016);
• "Understanding the distribution and trends in inshore fishing activities and the link to coastal communities": A Defra commissioned Cefas project to better understand trends in inshore fisheries around England and Wales, including collating and analysing fisheries sightings data from 2010 to 2012. These data were displayed as national layers of sightings (of certain fishing activities - trawling, potting, netting, etc) per unit effort (Vanstaen and Breen 2014); and

• "ScotMap": Fisheries mapping study undertaken by Marine Scotland to provide spatial information on the fishing activity of Scottish registered vessels under 15 metres in overall length. The dataset is based on interviews with 1,090 fishermen. The data is provided as data layers with information on monetary value, relative value, number of vessels and number of crew and is subdivided by fishing gear (Kafas et al 2014a).

It should be noted that approaches to the mapping of inshore activity based on qualitative information such as interviews, generally provide limited information on the intensity of the activity (i.e. information is limited to fishing location with no reference to frequency of fishing). In addition, these approaches may be limited in their ability to facilitate annual updates of information (Breen et al 2015). Furthermore, knowledge on fishing grounds and activities held by local fishermen and fisheries organisations, is generally difficult to standardise and quantify (MMO, 2014) and, in some instances, fishermen may have concerns over data and information sharing and confidentiality issues (Rodwell et al 2013).

The improvement of the evidence base on which inshore fisheries management decisions can be made is an aspect being developed across the UK as part of initiatives such as the Future of Our Inshore Fisheries Project (Seafish 2019) and the Future of fisheries management strategy (2020 to 2030) for Scotland (The Scottish Government 2020b).

It is to be expected that with the introduction of Inshore Vessel Monitoring System (IVMS) solutions for vessels under 12 metres in length, constraints on the accurate mapping of inshore fishing activities will be significantly reduced in the future. Marine Scotland is currently undergoing an inshore fleet tracking programme where funding has been issued for the installation of remote electronic monitoring and VMS equipment for Scottish inshore vessels (under 12 m). The roll out of IVMS systems for the inshore fleet is also under way in the rest of the UK.

In Scotland, a three-year project (2017- 2020) project focused on improving the management of inshore fishing activities, involving industry, academia and government (the Scottish Inshore Fisheries Integrated Data System (SIFIDS) project)) has recently been completed (MASTS 2021). The project saw more than 130 vessel skippers in 43 ports around Scotland host research trips, test tracking and/or devices installed, undertake surveys and significantly contribute to equipment and software development relating to inshore fisheries management. Key research undertaken as part of SIFIDS project included:

• Review and optimisation of shellfish data collection strategies for Scottish inshore waters;
• Development and pilot deployment of an autonomous fisheries data harvesting system;
• Investigation into the availability and adaptability of novel technological approaches to data collection;
• Development of a novel, automated mechanism for the collection of scallop stock data;
• Assessment of socio-economic and cultural characteristics of the Scottish Inshore Fishery;
• Capture and incorporation of experimental fisheries data;
• Development of a pilot recreational data resources for the collation and interpretation of inshore fisheries data;
• Development of a relational databased and user interface;
• Engagement with inshore sector to promote and inform;
• On board surveyors; and
• Identifying fishing activities and their associated drivers.

With increased availability of quantitative data for the under 12 metre fleet, consideration should be given to the development of methodologies to integrate this data with that available for vessels over 12 metres in length (i.e. VMS). The combination of spatial information from the two fleets would allow a comprehensive representation of all fishing activity in a given area (see Kafas et al 2014b).

Another aspect of importance to appropriately characterise fishing activities, both in inshore and offshore waters, relates to their seasonal and annual change. The latter is of particular importance to some fisheries such as scallop dredging, where the fishery shows a cyclical pattern, with good grounds rotating around the UK on a 7-8 year cycle (Cappell et al 2018). To date, spatial mapping of fishing activities used to inform marine spatial planning and impact assessments, tends to be presented as average data for various years or as annual data for a limited number of years (i.e. The Scottish Government 2019, DECC 2016, Vanstaen and Breen 2014, Kafas et al 2013; 2014a). In addition, it often includes little or no quantitative data to allow the identification of key fisheries seasonal constraints and long-term patterns and cycles. Guidelines for data acquisition to support marine environmental assessments of offshore renewable energy projects (Judd 2012) suggest that at least five years of fisheries data should be used to inform commercial fisheries assessments. However, the level of data ideally required to appropriately characterise seasonality and annual variations may vary significantly depending on the fishery and region under consideration and therefore may need to be considered on a case-by-case basis.

A summary of the key fisheries datasets currently available to inform commercial fisheries assessments is provided in Table 3.

Next steps in research

Aspects relating to the limitations of the existing fisheries data and their application for assessment of impacts from MRE projects have been and continue to be a key topic for discussion between regulators, researchers and fisheries stakeholders (Rodwell et al 2013, de Groot et al 2014). It appears that whilst currently available data allows the characterisation of fishing activity in a comprehensive way, the existing datasets are subject to various sensitivities and limitations, particularly when used to identify activity within localised, discrete, sea areas.

In addition, confidentiality and data privacy issues with regard to the activity of individual vessels and the use of broad gear categories not linked to specific fisheries/fleet segments in the VMS datasets, make the undertaking of assessments that accurately identify the relative importance of a given area to specific fisheries difficult. The limited quantitative data currently available for the under 12 metre fleet is also a key constraint to the accurate mapping of fishing activity. Whilst significant research and consultation has been undertaken to characterise the activities of the under 12 metre fleet around the UK, no specific guidance or standard methods have been developed to aid the integration of data from consultation in quantitative assessments or to facilitate the updating of data already collected on a regular basis.

With this in mind, the following next steps in research have been identified to address current knowledge gaps in respect of "Evidence Gap FF.01: Accurate mapping of fishing effort and catches in space and time":

• Development of detailed guidance in respect of data requirements to inform commercial fisheries impact assessments, including recommendations to facilitate analysis of seasonal and annual variations for key UK fisheries.
• Development of data layers which allow mapping of fishing activity by fleet segment or fishery.
• Development of methodologies to facilitate the integration of data and information collected through consultation with fisheries stakeholders into quantitative assessments and the regular update of such information.

The above would allow standardisation of the impact assessment process and facilitate the undertaking of more robust impact assessments, both at project specific level and in a cumulative context.