The first session offered an introduction to benthic invertebrates, their importance, and case studies from the WIO. Initial findings of the IIOE-2 expeditions in 2017 and 2018 considered the collection, preservation, cataloguing, and preliminary identification of benthic specimens utilizing a quality-assured workflow (Fig. 2). A WioBenth (https://www.wiomsa.org/ongoing-project/wio-wio-benth-identification-characterization-and-vulnerability-assessment-of-benthic-ecosystems-in-the-wio/) presentation focused on the identification, characterization, and vulnerability assessment of benthic ecosystems, with emphasis on shelf and upper slope habitats.

Session 2 discussed survey/sampling design and statistical considerations for robust use of visual sampling techniques, including key spatial, temporal, and ecological aspects. Lessons covered the design of effective monitoring strategies for Marine Protected Areas (MPAs), which prioritise declared objectives and monitoring of the effects of the main pressures on the MPA. Being an essential component of resource and adaptive management, monitoring was highlighted as means to providing science-based information to guide key management decisions to match park management plans*2. The critical importance of strong links between park management plans, monitoring data and outputs, and the communication of results in appropriate science-management forums, to the identification of management actions, was another focal point of this session. The fundamental importance of communicating monitoring results and management actions to external stakeholders to secure funding, garner support from local communities and form new collaborations was raised. Likewise, the use of Geographical Information Systems (GIS) (https://www.esri.com/en-us/what-is-gis/overview) to assist and standardize long-term monitoring techniques was highlighted as a rich source of information. However, while at present there are many (GIS) datasets freely available, users were reminded of the need to be cognisant of the limitations of such datasets (e.g. scale, resolution, completeness, and accuracy) to ensure that data are fit for purpose. The point was made that monitoring programmes could, and should, maximise institutional capacity and resources by addressing more than one objective, or pressure where applicable. The session concluded with examples of benthic monitoring projects conducted by the DFFE team using different sample designs.

Session 3 explored the suite of options available to collect marine benthic imagery (e.g. Drop-cameras, SCUBA, Baited Remote Underwater Video surveys (BRUVs), Towed Camera, Remotely Operated Vehicles - ROVs, Autonomous Underwater Vehicles (AUVs), and submersibles), which differ in technical complexity, cost, and the expertise required to deploy them (Fig. 3). Each of these methods come with their own advantages and limitations, and ultimately trade-offs between cost, time, required taxonomic resolution, and spatial coverage have to be made on a project-by-project basis. Lessons demonstrated how research objectives determine both the operational mode, i.e. exploring, searching, mapping, or monitoring, as well as the camera platform used, as these decisions will underpin the knowledge base required to effectively manage and conserve marine benthic environments*3. Gathering environmental data to validate and supplement visual data was also covered. In addition, step-by-step training videos providing detailed examples of the operation of frequently used benthic camera systems were a highlight of this event. The videos detailed how to set up, deploy and operate the camera systems, and included pre- and post- deployment protocols (Haupt et al. 2021, von der Meden et al. 2021).

Lessons and practical demonstrations in session 4 addressed the various software packages used to annotate videos and images (on both micro and macro scales) (e.g. Althaus et al. 2015, Langenkämper et al. 2017), as well as the types of analyses typically applied to image-based data (e.g. Cappo et al. 2003). The pros and cons of the most commonly used software packages for marine imagery annotation were discussed in relation to several criteria including cost, time constraints, technical expertise required, and type of information collected, by providing real-world examples and case studies. The consensus was that there is no single piece of annotation software that can simultaneously meet all research needs and objectives, hence, it is important to take steps that will allow for inter-comparability between research studies, including the use of standardised taxonomic vocabulary and open nomenclature signs*4.

In session 5, lessons and a training video (Bernard et al. 2021) were presented, focusing on how to conduct stereo-BRUVs-based research, covering field sampling, as well as experimental and equipment design (see review in Whitmarsh et al. 2016). Standard operating procedures and software options were also covered for the processing of single and stereo-BRUV footage in order to extract fish abundance and length data, perform benthic habitat descriptions, and carry out quality assurance and control procedures on datasets (see guide in Langlois et al. 2020)*5.

Session 6 focused on data management, from the administration and preservation of reference collections, to the procedures and tools needed to manage images/videos and data from marine biodiversity surveys. Imagery data promotes transparency as it is easily shared among academics and policymakers. As a result, it is possible to create digital archives that can be evaluated and utilized for teaching purposes. At present, large volumes of data are available to the WIO, which may provide excellent possibilities for individuals to become engaged in benthic research and develop new skills. However, most of this data is inadequately inventoried, structured, cleaned, or verified, and access to it is difficult. Data management practises should, as far as possible, conform to international standards to enhance standardisation. Researchers should consider depositing their data into data repositories, which are important tools for safeguarding data, ensuring long-term data preservation and making datasets visible and accessible to other users. Following the correct data management processes will add to the information enabling WIO researchers to better define benthic habitats, to find new species, and to develop other actionable contributions that can be used in spatial conservation planning and management*6.

The last session (7) was devoted to participatory talks in several breakout rooms focused on overcoming obstacles and moving forward with the use of underwater imagery in the WIO. The following topics were covered:

Best practices, which included regional-scale discussions regarding the best practices for habitat classification via benthic images, open data, common indicators for essential ocean variables and biodiversity reporting at local and regional scales,