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The Pomo (or Jabuka) Pits area is one of the main fishing ground for Norway Lobster Nephrops norvegicus and European hake Merluccius merluccius within the GFCM Geographical Sub Areas 17 (Northern and Central Adriatic Sea) and it is shared by the Italian and the Croatian fleets. Furthermore, this represents a well-known nursery area for M. merluccius and hosts a distinct population of N. norvegicus, characterized by small-sized mature individuals. Due to a decline in landing of both species for the Adriatic Sea, since 2015 the Italian and the Croatian governments implemented some protection measures in that area. Eventually in 2018, the GFCM established a Fishery Restricted Area. Since 2009 the area is yearly monitored by CNR IRBIM in collaboration with IOF Split. From 2009 to 2019 (except 2011 and 2018), a spring UWTV survey was conducted in the Pomo Pits area jointly by CNR-IRBIM Ancona and IOF Split, on board the CNR R/V Dallaporta; the Pomo Pits UWTV time series has been recently included, as a tuning index, in new modeling approaches tested for the Adriatic N. norvegicus stock assessment. Trials on automatic burrow tracking and counting have also been recently conducted on the Adriatic UWTV footage in the framework of the EU H2020 NAUTILOS project.

The Working Group on Nephrops Surveys (WGNEPS) is the international coordination group for Nephrops underwater television and trawl surveys within ICES. This report summarizes the national contributions on the results of the surveys conducted in 2022 together with time series covering all survey years, problems encountered, data quality checks and technological improvements as well as the planning for survey activities for 2023. In total, 21 surveys covering 26 functional units (FU’s) in the ICES area and 1 geographical subarea (GSA) in the Adriatic Sea were discussed and further improvements in respect to survey design and data analysis standardization and the use of most recent technology were reviewed. The first exploratory UWTV survey on the FU 25 Nephrops grounds was also presented to the group. The results of the evaluation of reference sets for FU3&4 Skagerrak/Kattegat were accepted following the process set down by the 2018 workshop (WKNEPS). An alternative method estimate Nephrops abundance was shown to the group using the recently published R package sdmTMB. The group agreed to hold a workshop in 2025 to address burrow size estimations to update correction factors and terms of reference for this to be agreed at next meeting. Automatic burrow detection based on deep learning methods continues to show promising results where datasets from multiple institutes were used. Plans are being progressed for an international Nephrops UWTV database to be established at the ICES data centre with a sub-group.

29/03/2022-Minor corrections to report formatting. The Working Group on Nephrops Surveys (WGNEPS) is the international coordination group for Nephrops underwater television and trawl surveys within ICES. This report summarizes the national contributions on the results of the surveys conducted in 2021 together with time series covering all survey years, problems encountered, data quality checks and technological improvements as well as the planning for survey activities for 2022. In total, 19 surveys covering 25 functional units (FU’s) in the ICES area and 1 geographical subarea (GSA) in the Adriatic Sea were discussed and further improvements in respect to survey design and data analysis standardization and the use of recent technologies were reviewed. Due to the COVID-19 pandemic there were minimal disruptions to survey operations where one survey was not completed (GSA 17). A trial trawl Nephrops survey offshore Portugal was carried out on the new research vessel. Preliminary work on how to measure burrow system size was presented using high definition (HD) and standard definition (SD) image data. Further work on comparison of SD and HD indicates the change to HD system mounted with a different camera angle was not significantly different for two survey areas (FU 16 and FU 20-21). Automatic burrow detection based on deep learning methods continues to show promising results where datasets from multiple institutes were used. The working group members have agreed to draft a roadmap for automatic system technology requirements with links to the Working Group on Machine Learning in Marine Science (WGMLEARN) and current researchers. The working group is progressing plans for an international Nephrops Underwater television (UWTW) database to be established at the ICES Data Centre. End-users of UWTV datasets for epifauna reporting presented their work and showed the potential for adding value to the survey data, where many of the institutes are involved in providing data for similar research purposes.

The Pomo (or Jabuka) Pits area is one of the main fishing ground for Norway Lobster Nephrops norvegicus and European hake Merluccius merluccius within the GFCM Geographical Sub Areas 17 (Northern and Central Adriatic Sea) and it is shared by the Italian and the Croatian fleets. Furthermore, this represents a well-known nursery area for M. merluccius and hosts a distinct population of N. norvegicus, characterized by small-sized mature individuals. Due to a decline in landing of both species for the Adriatic Sea, since 2015 the Italian and the Croatian governments implemented some protection measures in that area. Eventually in 2018, the GFCM established a Fishery Restricted Area. Since 2009 the area is yearly monitored by CNR IRBIM in collaboration with IOF Split

The rise of new technology is continuously generating gigantic datasets, known as “big data”. Imagery to tackle biological and ecological questions, is no exception. Observing and learning from these data is crucial but remains a tedious and labour-intensive process. This project aims to address to what extent computer vision based on deep learning can solve ecological questions while minimizing – if not removing human validation. For this purpose, a convolutional neural network (CNN) was trained on two types of data representing different sampling conditions and species communities. The first aimed at detecting the attraction levels of different types of biodegradable baits using baited remote underwater videos (BRUV). The BRUV footage analysis showed promising results with an average precision (AP), the standard metrics to assess the performance of deep learning models, of 0.827 for fish for the best performing model. An Interest index was introduced to assess each of the different bait types and a cockle bait functioned as the control. The resulting analysis – manual and automated - showed that the biodegradable plastic bait C17 has the greatest potential of replacing an old-fashioned cockle’s bait. The UWTV footage had more diverse classes (17 species, genus, or other taxa) and showed more mitigated results. The fish Callionymus spp., the crustacean Munida spp. and the Pennatulaceidae classes were accurately detected with AP values of 0.86, 0.82 and 0.80 respectively. In comparison, the main focus class Nephrops norvegicus slightly underperformed, with an AP value of 0.69. Other classes were more difficult to identify as such as “hydrozoa” and “crustacean” (AP of 0.23 and 0.24), due to their high diversity of shapes, colours and sizes. Nevertheless, in regard to other studies and given the challenging nature of marine-derived data, these values are satisfying. This project highlights the promising potential of replacing the labour-intensive human-validated analysis, while identifying the gaps that still need to be overcome. The generated models will help moving toward non-invasive methods with direct applications in marine conservation and fisheries management.

13 pages, 4 figures, 3 tables, supplementary Information https://doi.org/10.1038/s41598-021-85240-3, Underwater Television (UWTV) surveys provide fishery-independent stock size estimations of the Norway lobster (Nephrops norvegicus), based directly on burrow counting using the survey assumption of “one animal = one burrow”. However, stock size may be uncertain depending on true rates of burrow occupation. For the first time, 3055 video transects carried out in several Functional Units (FUs) around Ireland were used to investigate this uncertainty. This paper deals with the discrimination of burrow emergence and door-keeping diel behaviour in Nephrops norvegicus, which is one of the most commercially important fisheries in Europe. Comparisons of burrow densities with densities of visible animals engaged in door-keeping (i.e. animals waiting at the tunnel entrance) behaviour and animals in full emergence, were analysed at time windows of expected maximum population emergence. Timing of maximum emergence was determined using wave-form analysis and GAM modelling. The results showed an average level of 1 visible Nephrops individual per 10 burrow systems, depending on sampling time and depth. This calls into question the current burrow occupancy assumption which may not hold true in all FUs. This is discussed in relation to limitations of sampling methodologies and new autonomous robotic technological solutions for monitoring, This work received financial support from the Spanish Ministerio de Economía y Competitividad (Contract TEC2017-87861-R Project RESBIO, RTI2018-095112-B-I00 Project SASES and CTM2017-82991-C2-1-R Project RESNEP), from the Generalitat de Catalunya “Sistemas de Adquisición Remota de datos. This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CE

This document is the product of an expert group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the view of the Council. The Working Group on Nephrops Surveys (WGNEPS) is the international coordination group for Nephrops underwater television and trawl surveys within ICES. This report summarizes the national contributions on the results of the surveys conducted in 2019 together with time series covering all survey years, problems encountered, data quality checks and technological improve-ments as well as the planned for survey activities for 2020. In total, 19 surveys covering 25 func-tional units (FU's) in the ICES area and 1 geographical subarea (GSA) in the Adriatic Sea were discussed and further improvements in respect to survey design and data analysis, standardiza-tion and the use of most recent technology were reviewed. A new survey summary template by FU/GSA has been developed and adopted for future re-ports, which shall allow the data end users to extract the most relevant information on the survey results in a more easy way.Necessary actions and reviewer comments were addressed on the draft version of the Series of ICES Survey Protocols (SISP). Similarly, the working group reviewed the specifications for a Nephrops underwater TV database to be established at the ICES data centre and agreed on fur-ther action on this issue.First results from field studies on behaviour aspects of burrow emergence using bottom cages monitored by an automated camera system and on short-range migration using acoustic tracking are now available.Comparison of standard definition (SD) and high definition (HD) indicates the change to HD system mounted with a different camera angle may affect the detection rate and may thus require a revision of bias correction factors. New image reviewing software allows an easier way of an-notation of burrows than previous mosaicking methods, which has further advantages for inter-preting the results from different counters and for providing quality assured material for deep learning methods. The WG members agreed to collect information on burrow diameter size us-ing HD images and burrow annotation or mosaicking software because a change in the burrow size distribution may indicate recruitment events and the size of the burrow has an effect on bias correction factors in general. Automatic burrow detection based on deep learning methods applied to a test data set with an-notated burrow counts from a HD camera system showed promising results. The WG members were encouraged to provide more material with annotated burrow counts for further develop-ment of machine learning tools.

Harvesting the commercially significant lobster, Nephrops norvegicus, is a multimillion dollar industry in Europe. Stock assessment is essential for maintaining this activity but it is conducted by manually inspecting hours of underwater surveillance videos. To improve this tedious process, we propose an automated procedure. This procedure uses mosaics for detecting the Nephrops, which improves visibility and reduces the tedious video inspection process to the browsing of a single image. In addition to this novel application approach, key contributions are made for handling the difficult lighting conditions in these kinds of videos. Mosaics are built using 1-10 minutes of footage and candidate Nephrops regions are selected using image segmentation based on local image contrast and colour features. A K-Nearest Neighbour classifier is then used to select the respective Nephrops from these candidate regions. Our final decision accuracy at 87.5% recall and precision shows a corresponding 31.5% and 79.4% improvement compared with previous work [1].

Following the negative changes both in the population stock biomass and dmeographic structure of Norway lobster population in the Adriatic Sea special consideration should be given to the exploitation of this species. Since it is one of the most important commercial species exploted by the large fisheries fleet of all Adriatic countries, primary goal of fisheries scientist is to provide recommendations for sustainable exploitation of Norway lobster based on scientific conclusions. Use of the UWTV methodology together with trawl surveys in the future would allow systematic assessment of the Norway lobster stocks and contribute to identification and monitoring of year-to-year variation in biomass and size composition.

Underwater survey videos of the seafloor are usually plagued with heavy vignetting (radial falloff) outside of the light source beam footprint on the seabed. In this paper we propose a novel multi-frame approach for removing this vignetting phenomenon which involves estimating the light source footprint on the seafloor, and the parameters for our proposed vignetting model. This estimation is accomplished in a bayesian framework with an iterative SVD-based optimization. Within the footprint, we leave the image contents as is, whereas outside this region, we perform vignetting correction. Our approach does not require images with different exposure values or recovery of the camera response function, and is entirely based on the attenuation experienced by point correspondences accross multiple frames. We verify our algorithm with both synthetic and real data, and then compare it with an existing technique. Results obtained show significant improvement in the fidelity of the restored images., Funder: Science Foundation Ireland PI Programme: SFI-PI 08/IN.1/I2112

Video is an important tool in underwater surveys today, yet its useful field of view is restricted to image details within well lit regions on the seafloor. In this paper we present a novel vignetting-based weighting scheme for selecting these well lit details for use in the creation of a wide area view (mosaic) of the surveyed seafloor. Apart from this detail selection novelity,two other contributions are made. Firstly, because some of these scenes contain very little image texture, we introduce a hybrid homography estimation procedure that uses both feature-based and exhaustive searching techniques. Secondly, to facilitate cross referencing with the video, sections of the mosaic were indexed with the frame number in which the respective image details was selected from. We test our algorithm with real seabed survey video, whose scientific mission was population census of the particular species of lobster, Nephrops norvegicus. High quality mosaics were obtained that captured image details from well lit regions of the scene, which expert marine biologists agreed was a useful analysis tool. This work was supported by the Science Foundation Ireland PI Programme: SFI-PI 08/IN.1/I2112, and was done in collaboration with the Marine Institute Galway., Funder: Science Foundation Ireland PI Programme: SFI-PI 08/IN.1/I2112

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., Since 2003 a joint UWTV survey has been carried out by the Marine Institute(Ireland) and AFBI (Northern Ireland). For the first time in 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2010 survey for the western Irish Sea Nephrops stock. We also update the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the ninth data point in a time series of UWTV surveys on the ‘Aran grounds’. The survey covers three distinct mud patches; the Aran Ground, Galway Bay and Slyne Head. These have approximate areas of 940, 41 and 26 km2 respectively. For the first time in 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2010 survey and updates the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the fifth in a time series of UWTV surveys on the ‘Smalls grounds’. The 2006 survey covered the distinct mud patches of the Smalls Grounds and also indicator stations on the Labadie Bank, Nymphe Bank and Seven Heads, whereas the 2007 to 2010 survey covered the Smalls grounds only due to poor weather and time contraints. This report details the results of the 2010 survey for the Smalls ground Nephrops stock.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the ninth in a time series of UWTV surveys in the western Irish Sea carried out jointly by the Marine Institute, Ireland and the Agri-Food and Biosciences Institute (AFBI), Northern Ireland. The 2011 survey was multi disciplinary in nature and this report details the final UWTV results of the 2011 survey and also documents other data collected during the survey.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The prawn (Nephrops norvegicus) are common in the Celtic Sea occurring in geographically distinct sandy/muddy areas were the sediment is suitable for them to construct their burrows. The Celtic Sea area (Functional Units 19-22) supports a large multi-national targeted Nephrops fishery mainly using otter trawls and yielding landings in the region of ~6,000 t annually over the last decade (ICES, 2011). Nephrops spend a great deal of time in their burrows and their emergence behaviour is influenced many factors; time of year, light intensity and tidal strength. Underwater television surveys and assessment methodologies have been developed to provide a fishery independent estimate of stock size, exploitation status and catch advice (ICES, 2009 & 2011).This is the sixth in a time series of UWTV surveys in the Celtic Sea carried out by the Marine Institute, Ireland. The 2011 survey was multi disciplinary in nature and this report details the final UWTV results of the 2011 survey and also documents other data collected during the survey.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the fourth in a time series of UWTV surveys on the ‘Smalls grounds’. The 2006 survey covered the distinct mud patches of the Smalls Grounds and also indicator stations on the Labadie Bank, Nymphe Bank and Seven Heads, whereas the 2007 to 2009 survey covered the Smalls grounds only due to poor weather and time constraints. This report details the results of the 2009 survey for the Smalls ground Nephrops stock.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., Since 2003 a joint UWTV survey has been carried out by the Marine Institute (Ireland) and AFBI (Northern Ireland). In 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2009 survey for the western Irish Sea Nephrops stock. We also update the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The prawn (Nephrops norvegicus) are common around the Irish coast occurring in geographically distinct sandy/muddy areas were the sediment is suitable for them to construct their burrows. The Irish Nephrops fishery is extremely valuable with landings in recent years worth around €30m at first sale supporting an important indigenous processing industry. The Nephrops fishery “at the back of the Aran Islands” can be considered the mainstay of the Ros a Mhíl fleet. Without this Nephrops fishery the majority of vessels in the fleet would cease being economically viable (Meredith, 1999). Given these socio-economic realities, good scientific information on stock status to enable sustainable management of the resources are urgently required. This is the eight data point in a time series of UWTV surveys on the ‘Aran grounds’. The survey covers three distinct mud patches; the Aran Ground, Galway Bay and Slyne Head. These have approximate areas of 940, 41 and 26sq.km respectively. In 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2009 survey and updates the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the third in a time series of UWTV surveys on the ‘Smalls grounds’. The 2006 survey covered the distinct mud patches of the Smalls Grounds and also indicator stations on the Labadie Bank, Nymphe Bank and Seven Heads, whereas the 2007 and 2008 survey covered the Smalls Grounds only due to poor weather and time contraints. This report details the results of the surveys on the Smalls Grounds only to date.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This survey is carried out in co-operation with Marine Institute (Ireland) and AFBI (Northern Ireland) and is in its sixth year. A revision of the count data for the early years 2003 and 2004 is also presented where the initial high burrow estimates were checked and a drift in burrow identification was detected as detailed in SGNEPS 2009.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the second in a time series of UWTV surveys on the ‘Smalls grounds’. The 2006 survey covered the distinct mud patches of the Smalls Grounds and also indicator stations on the Labadie Bank, Nymphe Bank and Seven Heads, whereas the survey 2007 covered the Smalls Grounds only due to poor weather. This report details the results of the surveys on the Smalls Grounds to date.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., In 2007 the sixth in a series of annual UWTV survey was complete and the results of that survey together with a synthesis and analysis of the results. A geostatistical analysis indicates that burrow densities and abundances have fluctuated considerably in space and time. The highest densities occurred in 2004 and the lowest densities in the 2006.The 2007 survey shows an increase in burrow density. Using the survey directly for assessment and management is not yet possible. However, there appears to a negative relationship between abundance and landings in the autumn and a positive relationship between observed densities and landings the following spring. The relationship between abundance and landings is not as clear. There is no serious concern about the stock given the recent survey abundance.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The UWTV survey has been conducted on the western Irish Sea for a time series of 5 years. This report details the results of the surveys to date. The paper identifies a number of issues critical to the calculation of absolute abundance indices from the surveys and concludes that it is premature to have catch advice based directly on the survey although currently there is no serious concern regarding stock status on the western Irish Sea since burrow counts are still high.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The Nephrops fishery “at the back of the Aran Islands” is the mainstay of the Ros a Mhíl fleet and sustaining this valuable fishery would be at the heart of any management plan for fisheries in the area. In 2006 the fifth in a series of annual UWTV survey was completed, and the results of that survey together with a synthesis and analysis of the results were published. The survey is multidisciplinary in nature collecting data on burrow abundances from UWTV, Nephrops biological data from beam trawls, oceanographic data from CTD, sediment data, multi-beam and other habitat data. A geostatistical analysis indicates that burrow densities and abundances have fluctuated considerably in space and time. Highest densities occurred in 2004 with the lowest densities in the 2006 survey. There may be a negative relationship between abundance in landings in the autumn and a positive relationship between observed densities and landings the following spring.

Norway lobster, Nephrops norvegicus, is of great commercial importance throughout the NE Atlantic and Mediterranean, where it lives in burrows within muddy sediments. In several European countries it is assessed by means of towed underwater TV techniques. These are particularly suited to N. norvegicus because, for a number of reasons, the application of common fishery-dependent stock-assessment methods is not thorough for this species. The TV-based methodology relies on the fact that a known surface area of seabed is visually assessed and the number of N. norvegicus burrows, whose features are distinct, can be counted and their inhabitants quantified. It follows that, in theory, the same can be done for other organisms or key ecological features which appear on the footage. This study reports the results of the underwater television surveys (2009 and 2010) carried out jointly by Italy and Croatia in the Pomo/Jabuka pits, an area of the Adriatic Sea important for its N. norvegicus fishery and its hake nursery grounds. The obtained footage allowed quantification of the density of N. norvegicus in the area and the acquisition of estimates of the abundances of the squat lobster, Munida rutllanti and the sea pen Funiculina quadrangularis. The concurrent quantification of trawling activity from the footage has allowed us to place our results in the context of an ecosystem approach to fisheries management., Škamp ( Nephrops norvegicus ) je izuzetno važna gospodarska vrsta koja obitava u rupama u muljevitom sedimentu diljem sjeverno-istočnog Atlantika i Mediterana. Obzirom da uobičajene metode procjene bioloških resursa koje se zasnivaju na ribolovu nisu u potpunosti pogodne za ovu vrstu, nekoliko Europskih zemalja procjene populacije škampa obavlja korištenjem povlačne podvodne kamere. Ova metodologija bazira se na činjenici da škamp u sedimentu iskapa rupe karakterističnog izgleda koje se determiniraju i prebrojavaju vizualnim pregledom snimke dobivene povlačenjem podvodne kamere preko određene površine morskog dna. Teoretski, ova metodologija se može primijeniti i za procjene drugih vrsta ili ekoloških parametara koji su zabilježeni na snimkama. Ova studija iznosi rezultate istraživanja podvodnom kamerom (2009. i 2010. godine) koje su zajednički proveli Italija i Hrvatska na području Jabučke kotline u Jadranskom moru. Ovo područje koje se intenzivno gospodarski iskorištava značajno je kao glavno mrijestilište i rastilište većeg broja pridnenih vrsta, posebno škampa i oslića ( Merluccius merluccius ) Na osnovu dobivenih snimki izrađena je procjena brojnosti i biomase škampa, kao i procjena brojnosti hlapića ( Munida rutllanti ) i morskog pera ( Funiculina quadrangularis ). Istodobna procjena tragova koćarenja zabilježenih na snimkama omogućila nam je da ove rezultate stavimo u kontekst ekosustavnog pristupa gospodarenju bioloških resursa mora.

Harvesting the commercially significant lobster,Nephrops norvegicus, is a multimillion dollar industry in Europe. Stock assessment is essential for maintaining this activity but it is conducted by manually inspecting hours of underwater surveillance videos. To improve this tedious process, we propose the use of mosaics for the automated detection of burrows on the seabed. We present novel approaches for handling the difficult lighting conditions that cause poor video quality in this kind of video material. Mosaics are built using 1-10 minutes of footage and candidate burrows are selected using image segmentation based on local image contrast. A K-Nearest Neighbour classifier is then used to select burrows from these candidate regions. Our final decision accuracy at 93.6% recall and 86.6% precision shows a corresponding 18% and 14.2% improvement compared with previous work., Funder: Science Foundation Ireland PI Programme: SFI-PI 08/IN.1/I2112