Our SOx and NOx monitoring is finalist of the Greening Award Initiative

The monitoring programme of the Institute of Natural Sciences for SOx and NOx emissions of ships at sea, part of the aerial surveillance, is a finalist for the Greening Award Initiative of the European Maritime Safety Agency.

The Greening Award Initiative is jointly organised with Frontex (the European Border and Coast Guard Agency) and the European Fisheries Control Agency (EFCA) and celebrates the sustainability actions of authorities performing coast guard functions in the EU.

Since 2015, the Institute of Natural Sciences, using funding from the Connecting Europe Facility programme, has equipped the Belgian coastguard aircraft with a sniffer sensor to measure ship emissions of ocean-going vessels at sea.

This monitoring programme is successful thanks to good cooperation with the Minister of the North Sea who, among other things, provided the NOx sensor, and with the Directorate General Shipping, which organizes the follow-up of suspicious SOx and NOx values on land.

The aircraft now monitors for CO2, SO2, NOx, and black carbon, and the reports from its sniffer operations mean that port state control inspection efficiency has improved by over 50%.

Find out more about the programme at https://tinyurl.com/vkkzjr8k.

Aerial observations over the North Sea in 2023

In 2023, the Institute of Natural Sciences documented 17 cases of operational discharges from ships using the Coast Guard aircraft. Suspicious sulphur and nitrogen values were measured in the smoke plumes of 24 and 42 ships. Other activities included surveillance of oil and gas installations, marine mammal counts, and broader maritime surveillance for the Coast Guard.

© Ben Ullings

Overview of surveillance flights

A total of 244 flight hours were performed over the North Sea in 2023 as part of the national aerial surveillance programme. This programme is organised by the Scientific Service MUMM (Management Unit of the Mathematical Model of the North Sea) of the Institute of Natural Sciences, in collaboration with the Ministry of Defence.

Most of the flight hours were for national flights (221 hours):

  • 208 hours in the context of the Belgian Coast Guard:
    • 164 hours for pollution control, divided equally between the detection of discharges of oil, other harmful substances and garbage (MARPOL Annex I, II and V respectively) and the monitoring of sulfur and nitrogen emissions from ships (enforcement of MARPOL Annex VI);
    • 39 hours for fishery control, on behalf of and in cooperation with the Flemish Fishery Inspection Services;
    • 3 hours ‘on call’, during which flights were activated in response to specific alerts, namely for the verification of pollution near the windmill parcs and after the collision of two vessels;
    • 2 hours in the framework of a pollution combating exercise.
  • 13 hours for marine mammal monitoring.

In addition, 23 hours were dedicated to international flights in the framework of the Bonn Agreement, namely for a ‘Tour d’Horizon’ mission to monitor drilling platforms in the North Sea.

Discharges at sea

There were no accidental spills from ships in 2023. On the 10th of October, the Coast Guard Aircraft was requested to verify any pollution after the collision of two vessels in the Westhinder Anchorage. Only material damage was observed on scene.

On the other side, 4 operational oil spills were observed last year. Although this is the largest number in the past 5 years, the downward trend of the past 30 years remains standing (see graph).

The first oil pollution was observed in the wake of a fishing vessel, over a distance of one and a half kilometre. An official report was drawn up by the MUMM officers. The slick was not treatable.

A second, small-scale oil pollution was observed at the entrance of the Western Scheldt in Dutch waters. The oil slick could not be linked to a polluter and was already heavily weathered.

The third oil slick was located near the North Hinder shipping route and was larger in size. The spill of approximately 16 km2 covered French, English and Belgian waters and was already heavily weathered by the natural action of the waves and the large number of ships passing by. A possible polluter could not be identified.

The observation of the fourth oil slick happened after notification by the Norther windfarm. It concerned a small and already weathered oil slick near the wind farms. Here too, no polluter could be identified.

In 2023, no violations against Annex V of the MARPOL Convention concerning the discharge of solid waste from ships, including rubbish, fishing nets and solid cargo residues, were observed. However, no less than 13 cases of operational pollutions with noxious liquid substances other than oil (MARPOL Annex II) were observed. Of these 13 observations, 6 could be linked to a ship.

In 3 cases the discharged substance was FAME (fatty acid methyl ester), in the other cases the discharged substance consisted of aniline, sunflower oil and palm oil derivates. In one case, an official report was issued by the MUMM officers on board the aircraft, as one of the discharge rules for MARPOL Annex II was not met, which stipulates that such discharges must occur where the water is deeper than 25 meters. In the remaining cases, the competent port state control authorities were informed for further follow-up and investigation.

The discharge of harmful liquid substances other than oil is still a common problem, which, as reported in previous years, even appears to be on the rise (see graph below). Not only Belgium, but also other North Sea countries are noticing this increasing trend. However, the fact that these discharges often have a legal character does not alter the fact that they, to varying degrees of severity, can have a negative impact on the marine environment. It is important that coastal states continue to monitor these discharges, as this can identify problems at sea and provide an incentive to adapt, when necessary, current legislation.

Oil pollution in ports

On the 14th of December, an oil spill was observed in the port of Antwerp. This involved a historical pollution of oil released from the subsoil. This can occur for example during excavation or dredging works. At the moment of observation, an anti-pollution vessel was already trying to recover the oil.

Oil pollution in the port of Antwerp. © Institute of Natural Sciences/MUMM

Monitoring of sulphur and nitrogen emissions

By using a sniffer sensor, the Coast Guard aircraft can measure pollutants in ship emissions at sea, and our country is known as a pioneer in the international fight against air pollution from ships.

The measurement of sulphur emissions has already been part of the programme since 2016. In order to monitor the strict sulphur limits that apply to ship fuel in the North Sea Emission Control Area, 59 sniffer flights (for a total of 79,7 hours) were carried out by the aircraft in 2023 over the Belgian monitoring area. Of the 902 ships whose emissions were measured, 24 had a suspiciously high sulphur content. These ships were duly reported to the relevant maritime inspection services and were subsequently inspected on shore.

Thanks to the successful integration of a NOx sensor in 2020, the aircraft can also measure the concentration of nitrogen compounds (NOx) in the exhaust plumes of ships in order to monitor and enforce the stricter limits that apply from 1 January 2021 in the North Sea Emission Control Area. Belgium has thus become the first country ready to monitor these stricter restrictions. Of the 902 ships for which nitrogen emissions were monitored in 2023, 42 suspicious values were reported.

Since 2021, a new sensor has been added to the sniffer set-up, namely the black carbon sensor. This sensor measures the amount of black carbon in the exhaust plumes of ships, which is a measure for the soot concentration. The soot concentration of 377 ships was measured in 2023. When exceptionally high soot concentrations are measured, the competent maritime port authorities are asked to take a sample of the fuel used. In 2024, these fuel samples will be analysed by the Institute of Natural Sciences.

Checking for pollutants in the smoke plume of a ship. © Institute of Natural Sciences/ MUMM

International ‘Tour d’Horizon’ mission

In July 2023, the surveillance aircraft carried out the annual international TdH mission under the Bonn Agreement. During this mission marine pollution from oil rigs and gas installations are reported in the central part of the North Sea (in Dutch, Danish, British and Norwegian offshore waters).

A total of 30 oil spills were detected, the second highest number since the start of the Belgian participation to the yearly mission in 1991. 28 of these could be linked to oil rigs. All these observations were systematically reported to the competent coastal State for further follow-up, in accordance with international procedures.

Oil linked to a drilling platform during the international TdH mission. © Institute of Natural Sciences/MUMM

During this mission, the crew had the privilege of observing a pod of killer whales in Norwegian waters.

Three killer whales (Orcinus orca) in Norwegian waters during the international TdH mission. © Institute of Natural Sciences/MUMM

Monitoring of marine mammals

In 2023, the Institute of Natural Sciences conducted aerial marine mammals surveys in April, June and September. Respectively, 282, 32 and 55 harbour porpoises were observed along the flown transects. That are a lot of harbour porpoises for the Belgian waters: over 14.700 in April, 1.400 in June and over 2.500 in September. To a lower extent – but still quite frequently – also seals were observed, respectively 2, 10 and 30.

Extended maritime surveillance

Within the framework of the Belgian Coast Guard, the surveillance aircraft also contributed to broader missions of enforcement of maritime regulations and safety at sea.

As such, 15 ships were observed without AIS in 2023, an automatic identification system that, among other things, helps to avoid collisions. The majority (93%) were fishing vessels. The figures of 2023 confirm the increasing trend observed in the recent years, from the moment fishing vessels have been obliged to sail with AIS (in 2020).

In addition, 53 navigational violations were observed in the traffic separation scheme (“TSS”) in and nearby the Belgian waters. This is also a significant increase and mainly concerns vessels sailing in the opposite direction (“ghost sailing”) or dropping anchor in one of the shipping lanes. These observations were systematically reported to the Directorate-General for Shipping (FPS Mobility and Transport) for follow-up. In view of the increasing number of violations and the consequent increased risk of collisions, the Directorate-General for Shipping has been carrying out the necessary legal follow-up on this subject since January 2023.

Finally, 3 offenders who entered prohibited areas were also reported to the competent authorities. This is significantly less than the figures of previous years. A possible explanation is that the introduction of closed areas for shipping, such as the aquaculture farm (sea farm) off the coast of Nieuwpoort and the calibration area for scientific instruments (near Ostend) have already been established in the seagoing fleet.

© Institute of Natural Sciences/MUMM

Offshore wind farms and sediment dynamics

The number of offshore wind farms in the North Sea is exponentially increasing. Their construction responds to the urgent need to transition to green energy production and carbon neutrality. The installation of these man-made structures has a notable impact on the marine ecosystem. Some positive impacts include providing a new home for various animals, and offering shelter, food, and breeding grounds. However, there have been observations of black sediment patches in the sampled sediments near the turbine foundations, suggesting a high input of organic matter into the sediment, altering natural biogeochemical processes.

© Institute of Natural Sciences/E. Cepeda Gamella

In the OUTFLOW project, PhD candidate Esther Cepeda Gamella (Institute of Natural Sciences – MARECO and University of Ghent) investigates the source of these black sediments.

Find out more about this research in a blog article that Esther wrote for BioVox:


Starved young minke whale in Ostend

A young male minke whale that washed ashore in Ostend on May 13 most likely died of starvation. The empty stomach, the low weight and the thin layer of fat all point in that direction. The ‘fresh’ animal probably became separated from the mother for an unknown reason. Although sightings of dead and living minke whales have become more frequent in recent years in the south of the North Sea, their washing up on a Belgian beach remains an exceptional event.

© A. Deboosere

On the morning of May 13, 2024, a hiker found a dead, young minke whale (Balaenoptera acutorostrata) on the beach of Ostend, near the Casino Kursaal. Lead rescuer Jonathan Devos saw the animal – then still of unknown identity – floating in the coastal water shortly before. The area around the washed-up animal was cordoned off so that the emergency services and scientists from the Institute of Natural Sciences could organize the evacuation of the animal.

“It was immediately clear that it was a very young, very thin and only recently deceased animal,” says Jan Haelters, marine mammal expert at the Institute of Natural Sciences. “Minke whales measure only 2.5 to 2.8 m at birth, so we suspect that this 3.16 m specimen is only a few months old. At that age they are still highly dependent on their mother.”

From the fresh condition of the animal it can be deduced that it probably died shortly before, or during, the stranding. The cadaver was transferred to the Faculty of Veterinary Medicine of Ghent University, where a team from Ghent University and Liège University performed an autopsy the same afternoon.

© Institute of Natural Sciences/W. De Clercq

Autopsy Results

The Ostend minke whale turned out to be a young male.

“Its weight was only 214 kg, which is very little for an animal of this size. Even at birth they weigh heavier, up to 450 kg. It was therefore not surprising that no food remains were found in the stomach,” says Wannes De Clercq, who attended the autopsy for the Institute of Natural Sciences.

“The findings suggest that this minke whale became separated from its mother, which is obviously problematic for a young animal that cannot yet provide for its own food supply” Wannes added. The thin layer of blubber (only 7 mm thick) also supports the hypothesis of death by starvation. A small piece of plastic in the stomach is not related to the death.

© Institute of Natural Sciences/W. De Clercq

Belgian Minke Whales

The minke whale is a permanent resident of the North Sea, but its range is mainly limited to the northern and central part of it. The species appears less often in the south of the North Sea, although the frequency of sightings of living and washed-up minke whales seems to have increased here in recent years.

Jan Haelters provides details: “We know of eleven proven cases of minke whales in Belgian waters over the last 25 years. Five times it involved carcasses and six times it involved sightings of live specimens.”

The carcasses date from 2004 (found dead at sea and brought ashore; died from bycatch), 2013 (stranded; died from swallowing a large amount of plastic), 2017 (decomposing carcass at sea), 2020 (malnourished and broken lower jaw) and 2023 (decomposing carcass at sea, later washed up in the Netherlands).

The living minke whales were spotted in 2013, 2017, 2019, 2020 and twice in 2024. The latter animals were observed on March 20, 2024, from the RV Belgica by scientists from the Research Institute for Nature and Forest (near the Fairybank) and on April 23, 2024, during an aerial survey of marine mammals by the Institute of Natural Sciences (near the border with English waters).

Close cooperation between Belgium and France at sea this summer

Joint operation on security under the European flag

On May 13th, 2024, the official kick-off of a temporary Belgian-French collaboration on the use of drones on the North Sea coast was given in Dunkirk, France. For four months, from May 13 to September 13, 2024, the partners of the Belgian Coast Guard will be able to use two special drones to support their various tasks at sea. This also includes the Management Unit of the Mathematical Model of the North Sea and the Scheldt Estuary (MUMM), scientific service of the Institute of Natural Sciences.

© EMSA/Schiebel

This joint operation by Belgium and France is coordinated by EMSA and EFCA, the European Maritime Safety Agency and the European Fisheries Control Agency, respectively. The project is called MMO (Multipurpose Maritime Operation) La Manche and Southern North Sea and is therefore cross-border.

This summer, even more eyes will be focused on the sea to ensure the safety of our coastal area. In addition, many training courses on maritime safety are organized by international experts.

Nathalie Balcaen – co-chair of the Coast Guard: “This is a great opportunity that we get from EMSA and EFCA. In an initial phase, we want to see how these drones can supplement the resources we already have. How can the devices help with a sea rescue operation or hydrography? Are they the right types or not? We can fully use the material from the summer and then evaluate it. If the results are positive, we will work on the necessary files to purchase drones ourselves.”

Two types of drones will be deployed together with France. A so-called RPAS (Remotely Piloted Aircraft System), a flying drone, and an ROV (Remotely Operated Vehicle), an underwater drone. Various Coast Guard partners will be able to deploy these drones in pre-defined zones of the North Sea.

Use of drones

  • The MRCC (Maritime Rescue and Coordination Center) of the Maritime Services and Coastal Agency (MDK) wants to use the RPAS for Search & Rescue. For example, the drone can take images of any ‘anomalies’ at sea such as small boats, drowning people, objects, etc. In the event of a collision between two ships off the coast, the drone can be sent ahead to determine any damage to the ships at an early stage. This makes it possible to intervene even more quickly in the event of a maritime disaster.
  • The DG Environment and the MUMM (Management Unit of the Mathematical Model of the North Sea and the Scheldt Estuary) want to use the RPAS to detect environmental pollution. MUMM can also use the drone additionally to verify certain reports about fauna and flora in the North Sea or for measuring emissions from vessels.
  • The Agriculture and Sea Fisheries Agency wants to use the RPAS for assignments in the context of fisheries control at sea.
  • The Flemish Hydrography Service (Maritime Services and Coastal Agency – MDK) will use the ROV, among other things, to better visualize and identify wrecks on the bottom of the North Sea.

Additional training and exercises

Education and training for the various Coast Guard partners are also provided within the framework of the MMO, in addition to using the technology. The focus here is on even better identification of ships at sea and associated communication. For example, from its headquarters in Lisbon EMSA’s Integrated Maritime Services (IMS) will provide a detailed live image of all vessels on the Channel, one of the busiest sea routes in the world. Special algorithms will be able to track the movements of ships. Together with satellite images, these IMS will provide a lot of data to gain a complete picture of maritime traffic. Belgium and France will also be able to use satellite images from EMSA’s CleanSeaNet Oil Spil Monitoring and Pollution Detection Service.

In the context of the MMO, the DG Environment will also be able to extensively practice an oil response component. On May 14 and 15, the Belgian and French oil response capabilities will be tested during a large-scale exercise. In a fictional scenario, a tanker will lose a substantial amount of oil after a collision off the French coast. France will call on Belgian ships to help combat pollution. Three Belgian ships and a ship from the European agency EMSA will work in formation to remove the oil from the sea.

The Belgian Coast Guard aircraft, operated by the Institute of Natural Sciences and Defense, also takes part in this exercise, and the ecochemical laboratories (group ECOCHEM – Ecosystems Physico-Chemistry) of the Institute of Natural Sciences also play an important role. They receive oil samples via helicopter transport to carry out an oil fingerprinting (process to determine the origin of an oil sample). The results are compared with those of the French, so that the information exchange protocol can also be tested.


Addenda: Aerial images of the simulated oil spill, taken during the exercise of 14-15 May 2024 from the Belgian Coast Guard airplane.

© Institute of Natural Sciences/MUMM
© Institute of Natural Sciences/MUMM

15 years of monitoring the ecological effects of Belgian offshore wind farms still yields new insights

Fifteen years into the programme, monitoring of the ecological effects of Belgian offshore wind farms continues to provide new insights. That is an important conclusion of the latest WinMon.BE report that summarizes the findings on bottom-dwelling invertebrates, fish, harbour porpoises and birds. Only through sustained and adaptive monitoring can we ensure that we design and build offshore wind farms in the most eco-friendly way.

Scientific fieldwork in the Belgian offshore wind farms with the RV Belgica. (Image : Institute of Natural Sciences/MARECO)

At present, eight offshore wind farms are operational in the Belgian part of the North Sea, totalling an installed capacity of 2.26 Gigawatt (GW) and consisting of 399 offshore wind turbines. Together they occupy an area of 238 km² along the border with Dutch waters and produce an average of 8 TWh annually. This accounts for around a third of gross electricity production from renewable energy sources in Belgium.

The impacts on the marine ecosystem, both positive and negative, have been investigated through the WinMon.BE monitoring and research programme from the very start of the construction of the first wind farm in 2008. The scientific insights obtained have always informed the management and development of this first Belgian offshore wind farm zone. In their latest report, scientists of the Institute of Natural Sciences, the Research Institute for Nature and Forest (INBO), the Marine Biology Research Group of Ghent University and the Research Institute for Agriculture, Fisheries and Food (ILVO) discuss the latest findings from 2022, summarize some trends from 15 years of monitoring, and identify where additional research and the development of additional mitigation measures is needed.


Long-term impacts of offshore wind farms on the macrobenthic communities (roughly the organisms that live on the seabed and are visible to the naked eye) that inhabit the surrounding natural soft sediments were investigated over a time span of 13 years (2008–2020). The sediments around and between the wind turbines were also studied in this context.

Because wind turbines interfere with water currents, fine sediments settle more easily here. The sediments in wind farms also get organically enriched by the feces of organisms that colonized the turbines themselves (such as mussels, anemones and crustaceans), and by dead animals that fall from the turbines. For the macrobenthos, a higher abundance, species richness and diversity was found around the wind turbines. Furthermore, higher abundances were also documented in the gullies between sandbanks on which the wind farms are typically constructed. The macrobenthos community continues to change, no stable state has yet been reached after 13 years of offshore wind farm operations.

In addition, macrobenthic diversity, abundance and species richness were also correlated with climate-related predictors (sea surface temperature and its natural variability on a time scale of several decades) which demonstrates the importance of also including such environmental variables in the study.

Demersal Fish

Changes in species distribution patterns were identified for demersal fish, as exemplified for plaice Pleuronectes platessa, a species extensively studied in terms of its spatial distribution, diet and movement patterns in relation to offshore wind farms. A combination of visual diving transects (at the turbine scale), beam trawl samples (at the wind farm scale) and the follow-up of tagged animals demonstrated the significance of the scour protection layer and the sandy patches in between the turbines as a feeding habitat for plaice.

The findings suggest that offshore wind farms serve as a refuge for plaice, potentially mitigating direct fishing mortality and likely enhancing plaice production. It was previously documented that fishing vessels caught more plaice for the same fishing effort just outside the wind farms than at the same places before the construction of the wind farms. However, it remains to be investigated whether this is a true spillover effect that continues to manifest itself in the longer term, and also in the context of the anticipated large-scale expansion of offshore renewable energy zones in the broader North Sea.

Harbour Porpoise

Altered species distribution patterns in relation to the presence of offshore wind farms are not independent of other human activities, such as shipping, fisheries and mariculture. This is particularly the case for highly mobile species like marine mammals. Aerial survey data (2009-2022) allowed for an analysis of the distribution patterns of the harbour porpoise Phocoena phocoena in function of both environmental drivers and anthropogenic stressors.

The distribution of harbour porpoise followed a consistent seasonal pattern, with the highest densities in spring. It was shown that the species prefers the western part of the Belgian North Sea waters, revealing a strong overlap with the marine protected area ‘Vlaamse Banken’. The distribution was also negatively correlated with marine traffic intensity and distance to the closest offshore wind farm. However, it is essential to exercise caution to avoid overinterpreting these correlations. Further monitoring and research is recommended to better understand the interaction between natural factors, such as prey availability, and anthropogenic stressors, driving the spatial distribution of harbour porpoises.

Harbour porpoises documented during an aerial census. (Image : Institute of Natural Sciences/J. Haelters)


The monitoring strategy for seabirds not only aims to detect displacement responses, it is also designed to detect avoidance (or attraction) distances and the effect of turbine density on seabird displacement. The results presented at this stage (data from February 2021 to April 2023) need to be considered as indicative since more data and advanced spatial modelling are needed.

Nevertheless, based on the currently available data, it is interesting to see that the observed responses are in line with what has been found before and elsewhere for several seabird species. The results indicate an attraction effect for great black-backed gull Larus marinus and great cormorant Phalacrocorax carbo, and an avoidance effect for northern gannet Morus bassanus. On the other hand, avoidance of common guillemots Uria aalge was no longer noticed and an increased number of razorbills Alca torda was observed in the wind farms.

Northern Gannet in the Belgian part of the North Sea (Image : Institute of Natural Sciences/K. Moreau)

Migrating Birds

As the southern North Sea is one of the main migration flyways in Europe, mitigating the impacts of offshore wind farms also entails measures to reduce collision numbers for migrating birds. The highest flight intensities at sea are recorded at night during spring and autumn migration, mainly of migrating passerines. Normally, these migrate at higher altitudes, but a portion flies at rotor height of the wind turbines and are thus at risk of collision. Especially adverse weather conditions bring large numbers of passerines into the range of the turbine rotors.

Temporarily stopping the turbine operation during high collision risk events for songbirds is expected to substantially prevent collision mortality. However, this management measure has not yet been applied regularly but has already been tested in the Netherlands, among others. Site-specific monitoring programmes remain necessary to assess the effectiveness and the finetuning of the measure. Furthermore, a regional approach may be most appropriate to maximize the efficiency and ecological benefits of such measure.

Long-Term and Adaptive Monitoring

Most environmental monitoring programmes for offshore wind farms are halted five years after installation. WinMon.BE, on the other hand, has adopted a philosophy of long-term investigation, spanning the full life cycle of offshore wind farms, from construction through the operational phase to the final decommissioning. The programme shows that progressive changes in the marine ecosystem are still observed fifteen years after the first installation of offshore wind turbines in the Belgian part of the North Sea, as was the case for the macrobenthos communities. This underlines the importance of long-term research for a sound offshore wind farm management.

The monitoring programme must also be adaptive. Not only continued, but also new research is indispensable to further the understanding on how marine ecosystems respond to wind farms. This research should not only focus on the attraction of hard substrate species (with wind turbines representing artificial hard substrates), but also on species that are less evidently impacted by offshore wind farms, such as plaice and other demersal fish.

Steven Degraer (Institute of Natural Sciences/MARECO), coordinator of the WinMon.BE consortium: “We need to keep critically reflecting on the efficiency and effectiveness of the monitoring and research programme to ensure that we collect the best data, as shown with the re-designed monitoring programme for seabirds. As demonstrated for marine mammals, we need to address the most pertinent questions and contextualise offshore wind farm effects. Progressive insights are necessary to feed evidence-based, efficient and effective mitigation measures, and to develop and design eco-friendly offshore wind farms”.

It’s not over yet for WinMon.BE

An additional Belgian zone for offshore renewable energy, the Princess Elisabeth Zone, anticipating an installed capacity of between 3.15 and 3.5 GW on an area of 285 km², has been designated in the marine spatial plan 2020-2026. The progressive insights of WinMon.BE are also used to guide the design of this zone in an environment-sensitive manner, and also during the construction and operational phases of future wind farms, WinMon.BE will document and learn to understand the effects on the marine ecosystem. As the Princess Elisabeth Zone overlaps with the marine protected area ‘Vlaamse Banken’, additional knowledge on the nature-inclusive design of wind farms was gathered in the EDEN2000 study “Exploring options for a nature-proof Development of offshore wind farms inside a Natura 2000 area” (2019-2023).

Zones for renewable energy, including offshore wind farms, in the Belgian part of the North Sea. Eastern zone (green) = first phase that is completely operational; western zone (blue) = Princess Elisabeth Zone; orange dotted line = Natura 2000 area (source: Marine Spatial Plan 2020-2026)

Moreover, Belgium is not the only country that is investing in wind farms in the southern North Sea. Many parks are already operational, under construction or planned in our neighboring countries, and there is a declaration of intent to install 300GW of wind energy in the North Sea by 2050. Therefore, cumulative ecological effects on a larger geographical scale than the Belgian part of the North Sea are also a concern. The results of WinMon.BE and EDEN2000 can also be directly used in the context of the Greater North Sea Basin Initiative, which strengthens cooperation on marine spatial planning between the North Sea countries. An additional reason why it is important that the monitoring of the ecological effects of offshore wind farms continues!

“WinMon.BE still has a long future ahead of it. It is also encouraging that the programme serves as an example for the environmental monitoring in offshore wind farms in an international context. Discussions are ongoing with policymakers and scientists from various countries, who wish to draw inspiration from the Belgian example” Steven Degraer concludes.


About WinMon.BE

The Monitoring Programme WinMon.BE is commissioned by the Federal Government as part of the environmental permit conditions for offshore wind farms. For the monitoring, use was made of the research vessel Belgica (ship time on RV Belgica was made available by BELSPO and the Institute of Natural Sciences), the research vessel Simon Stevin (operated by the Flanders Marine Institute), several private vessels, the Belgian scientific diving team and the aerial surveillance aircraft of the Institute of Natural Sciences.

WinMon.BE is a cooperation between the Institute of Natural Sciences, the Research Institute for Nature and Forest (INBO), the Marine Biology Research Group of Ghent University and the Research Institute for Agriculture, Fisheries and Food (ILVO), and is coordinated by the Marine Ecology and Management team (MARECO) of the Institute of Natural Sciences. MARECO also coordinated the EDEN2000 study with respect to the anticipated ecological effects of future offshore wind farms in the Princess Elisabeth Zone.

Common dolphin stranded on the beach of Ostend

On the morning of Friday 22 December 2023, a dead Common dolphin (Delphinus delphis) washed up on the beach of Ostend, near the western harbour wall. It was a female measuring 2.07 meters in length.

© Institute of Natural Sciences / Jan Haelters

The Common dolphin is a rare species in the North Sea but is the most common dolphin species in the Bay of Biscay and in the adjacent Atlantic Ocean. In the Bay of Biscay, thousands die in fishing nets every year.

© Institute of Natural Sciences / Jan Haelters

It was no less than the third time in 2023 that a dead Common dolphin washed up on a Belgian beach, which is very exceptional. The specimen on 22 December was by far the freshest of the three and was therefore collected for further research. However, this will not take place until 2024, and will hopefully shed light on the health condition, cause of death and area of origin of the unfortunate animal.

© Institute of Natural Sciences / Jan Haelters

Public consultation: Application for an environmental permit for sand extraction

Betoncentrale Van den Braembussche has applied on October 31th, 2023 for the prolongation of its concession for sand extraction in the Belgian part of the North Sea. This application is subject to an environmental impact assessment procedure.

The application and the environmental impact assessment report, including a design of appropriate assessment, can be downloaded below (in Dutch).


Environmental impact assessment report (original 2020)

Environmental impact assessment report (update 2022)

Environmental impact assessment report (annex study day 2021)


Results of the consultations

Objection 4Sea-20240112


The public consultation runs from December, 8th 2023 until January, 7th 2024.

Any interested party can submit its views, comments and objections to Ms. Brigitte Lauwaert by letter or email until January, 22th 2024.

Institute of Natural Sciences/MUMM
Attn. Ms. Brigitte Lauwaert
Vautierstraat 29
1000 Brussels


Quality Status of the North-East Atlantic

In the Quality Status Report 2023, the 16 contracting parties to the OSPAR Convention, including Belgium, assess the status of the Northeast Atlantic Ocean. The report confirms that climate change and ocean acidification have become drivers of major change. Biodiversity and habitats remain at risk, but a turnaround is noticed with respect to the chemical quality of the marine environment.

More than 400 scientists and policy makers from around the North-East Atlantic have worked together to produce a holistic assessment of the North-East Atlantic marine area: the OSPAR Quality Status Report 2023 (QSR). The work was carried out under the umbrella of the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic. It examines the current state of the marine environment and ecosystems, and the human activities benefiting from the marine environment and interacting with it.

Dr Patrick Roose, Operational Director of the Department ‘Natural Environment’ of the Institute of Natural Sciences was one of the coordinators of this titanic work. He summarizes the situation as follows: “There is an ever-more pressing need to address drivers of degradation and biodiversity loss and thereby increase the health and resilience of marine ecosystems in the North-East Atlantic. This area also includes our North Sea. Climate change and ocean acidification have now become drivers of major changes that imperil much of the North-East Atlantic’s marine biodiversity. As such, they now add to the effects of the hitherto ‘traditional’ drivers, such as overexploitation and chemical pollution.”

Biodiversity in peril

The report shows that many parts of the North-East Atlantic still suffer from declining biodiversity and continued habitat degradation, despite the measures that have already been taken by OSPAR Contracting Parties. The impacts of fisheries and other human activities on biodiversity and habitat quality are still deeply felt, and other forms of degradation such as noise pollution are of growing concern.

Although the status of habitats and individual species varies greatly, some general statements can be made: Benthic habitats continue to be damaged, whereas plankton, the base of the marine food web, is impacted in pelagic habitats. The state of marine food webs is of great concern. More and more fish stocks are being fished sustainably, but the overall status of marine fish remains unfavorable. Marine birds are generally still in trouble. Many marine mammals, especially northern seal populations and small toothed cetaceans, remain at risk while the status of some other marine mammals remains unknown. We also appear to know relatively little about the status of marine turtles.

Areas of improvement

Fortunately, the environmental quality has improved in some areas: The most serious hazardous substances such as PCBs, PAHs, and organochlorides remain a cause for concern (mostly because they remain in the system for a long time), but releases have decreased substantially. Pollution by radioactive substances has been prevented, and discharges by the oil and gas industry have been greatly reduced and continue to decrease. Marine litter levels remain high but are better tracked, with significant steps having been taken to reduce it.

Eutrophication, the process in which a water body becomes overly enriched with nutrients, persists but a gradual reduction of the excess nutrients has been witnessed in many parts of the North-East Atlantic. The introduction of new non-indigenous species, another traditional driver of biodiversity loss, also appears to have decreased in the marine environment. As a community, we must ensure that we continue these trends in the right direction. Furthermore, we must also be careful with optimism in the face of climate change and ocean acidification. After all, the impacts of these man-caused phenomena are now clearly measurable and put ecosystems at further risk.

Appropriate measures

The findings from the Quality Status Report 2023 will be used to help OSPAR deliver its North-East Atlantic Environment Strategy 2030, a roadmap to achieving the vision of a clean, healthy and biologically diverse North-East Atlantic Ocean, which is productive, used sustainably and resilient to climate change and ocean acidification.

Dr Roose provides some important nuances: “The general conclusions of the QSR contain no major surprises, but we must become better at developing the necessary science-based policy, and therefore at translating scientific insights into effective measures. To be effective, we need to pool our efforts and move to international evaluations and joint measures. It makes no sense to assess everything on a national basis as there are no borders in the seas, and no undesirable effects can be overcome in national parts of a bigger basin.”

There is also additional work to be done for science: “Still, there are indicators for which we have insufficient data and can better coordinate the data collection. Sufficient, continuous and coordinated data collection is key, in other words, so is continuous policy support. Also, not all assessment methods and thresholds are already sufficiently established, particularly for cumulative effects” Dr Roose adds.

Dr Patrick Roose presenting the key findings of the OSPAR Quality Status Report 2023 at the Annual Science Conference of the International Council for the Exploration of the Sea (ICES) in Bilbao, Spain, 13 Sep 2023.

About OSPAR and the QSR

OSPAR – the Oslo and Paris Commission – is the mechanism by which 15 Governments and the EU cooperate to protect the marine environment of the North-East Atlantic. The fifteen Governments are Belgium, Denmark, Finland, France, Germany, Iceland, Ireland, Luxembourg, The Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

OSPAR started in 1972 with the Oslo Convention against dumping and was broadened to cover land-based sources of marine pollution and the offshore industry by the Paris Convention of 1974. The two conventions were unified, updated and extended by the 1992 OSPAR Convention. A new annex on biodiversity and ecosystems was adopted in 1998 to cover non-polluting human activities that can adversely affect the sea. More information on the OSPAR website and YouTube.

The Quality Status Report (QSR) 2023 is the most authoritative assessment of the whole North-East Atlantic and reflects the collective work of the 16 Contracting Parties to the OSPAR Convention. It assesses the status of various components of the North-East Atlantic and examines how conditions have changed since the last QSR in 2010.

Publication of the QSR 2023 was announced at the Annual Science Conference of the International Council for the Exploration of the Sea (ICES) in Bilbao, Spain, on September 13, 2023. In Belgium, the results, with a focus on the North Sea, were presented during the event ‘Nature restoration in our North Sea’, organized by the FPS Public Health, Food Chain Safety and Environment, on December 5, 2023 in Bruges.

The Belgian input for the QSR came about thanks to the cooperation of many actors, all of which are explicitly thanked for their cooperation: the Directorate-General for the Environment (FPS Public Health, Food Chain Safety and Environment), the Institute of Natural Sciences, the Federal Agency for Nuclear Control (FANC), the Flanders Environment Agency (VMM), the Research Institute for Nature and Forest (INBO), the Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), the Flanders Marine Institute (VLIZ), Maritime Access (Department Mobility and Public Works), the Public Waste Agency of Flanders (OVAM) and the Directorate-General Shipping (FPS Mobility and Transport).

Conservation priority of stony reef habitats in the Belgian North Sea

Stony reefs in the Belgian North Sea host a unique fauna that is highly vulnerable to bottom-disturbing activities. Currently, these reefs are targeted by bottom-contacting fisheries. This paradox  underpins the urgent need for a more effective protection of marine gravel beds and their fauna.

Figure 1. Indicative overview of the variable life forms found in the Belgian stony reef areas. (A) the soft coral Alcyonium digitatum (B) the common spider-crab Maja brachydactyla (C) the small-spotted catshark Scyliorhinus canicula (D) the branching hydrozoan Nemertesia spp. (© Institute of Natural Sciences/MARECO)

The Belgian seafloor consists primarily of soft sediments that form a widespread and very prominent geomorphological system of large sandbanks. However, approximately. 16% of the seafloor is composed of natural hard substrates, typically referred to as “stony reefs” or “gravel beds”. These stony reefs, ranging from gravels to pebbles, cobble stones and larger boulders, are patchily distributed over the predominantly sandy seafloor.

Stony reef areas provide a stable holdfast for a unique, diverse and specialized fauna. Several organisms, such as soft corals and branching hydrozoans or bryozoans, form complex three-dimensional body structures. These areas, characterized by increased habitat complexity and heterogeneity compared to the surrounding sandy environment, act as oases and serve as refuge, settling, foraging, spawning and nursery grounds for organisms at various levels of the food web. Many of these are of commercial and conservation importance (Fig. 1). These habitats are as ecologically valuable as they are fragile and they are highly susceptible to anthropogenic disturbances, including bottom-contacting fisheries.

Minimally invasive research

Gaining a deeper understanding of the effects of commercial bottom-disturbing fisheries on stony reefs in the Belgian North Sea was the goal of the investigation led by Giacomo Montereale Gavazzi and fellow researchers from the MARECO group (Marine Ecology and Management) of the Institute of Natural Sciences. Their results, spanning a period of 7 years (2016-2022), are presented in a 2023 publication in the scientific journal Frontiers in Environmental Science.

The study focused on two distinct offshore stony reef areas in the Belgian part of the North Sea: the Northwest and the Hinder Banks (Fig. 2). The Northwest site, first observed in 2018 and celebrated as a biodiversity hotspot, has been designated as a search zone for biodiversity protection, but also as a prospecting area for marine aggregate extraction under the Marine Spatial Plan 2020-2026 that is currently in force. The Hinder Banks site partly overlaps with the Marine Protected Area ‘Vlaamse Banken’ under the EU habitats Directive, which was delineated in 2012 to protect reefs and sandbanks.

Figure 2. Overview of the stony reef study areas (red outlined polygons) in the Belgian part of the North Sea (black polygon). The larger of the two study sites (Hinder Banks) is situated inside the Natura 2000 area (green outlined polygon), with the overlapping blue polygon delineating the planned area for future renewable energy development. The blue polygon at the border with the Netherlands marks the current renewable energy zone with operational offshore wind farms. (© Institute of Natural Sciences/MARECO)

Given the fragility of these habitats, the research team relied solely on minimally invasive remote sensing technologies. Commercial fishing activity data (mapping the spatial and temporal distribution of fisheries), echo sounding (seabed mapping with sound waves) and underwater photography (documenting the structure and fauna of the seabed) were combined to provide a comprehensive overview of the ecological status of the two areas. The data analysis confirmed that both were hotspots for bottom-contacting fisheries during the studied period.

Reefs as fishing hotspots

The Northwest site has experienced a boom in fishing activities from 2021 to 2022 (32% increase in the number of operating vessels), with an overall extent of the area disturbed reaching 86%. In the Hinder Banks area, the estimated disturbed area was calculated at 89%, and while fishing activities decreased by 60% from 2021 to 2022, this site has been chronically under very high fishing pressure going back for centuries.

This intense fishing pressure is reflected in the response of the stony reef benthic communities. These shifted from immobile, long-living and habitat-forming taxa with low resistance and recovery potential to disturbance (typical of such habitats) to opportunistic taxa lacking these typical characteristics. The effect that bottom-trawling has on the seafloor was also evident by the trawl marks captured by the hydroacoustic surveys (Fig. 3), appearing as plough marks scarring and smoothing the geomorphology, with their impact persisting for at least four months. The overall results showcase that bottom-contact fishing practices can have detrimental effects on the ecological functionality of these conservation priority biotopes.

Figure 3. Display of trawling marks scarring the seafloor when bottom-contact fishing gears are used. Examples from two locations at the Northwest stony reef site. (© Institute of Natural Sciences/MARECO)

Marine Spatial Planning

While both study sites are subject to different environmental management regimes, they share a common challenge with respect to ongoing direct anthropogenic disturbance. Considering that the Hinder Banks area is designated as a Marine Protected Area, it becomes evident that this legislative status alone is insufficient for achieving the desired protection level. More comprehensive regulations are in trajectory under the current Marine Spatial Plan. Both stony reef sites have been designated as search zones for seafloor protection with the intention of restricting bottom-disturbing fishing practices to facilitate nature restoration and conservation.

The study by Montereale Gavazzi and his colleagues provides additional scientific information to be considered for the next Marine Spatial Plan and as such supports the protection of local natural biodiversity. It strongly advocates for adequate regulation of bottom-disturbing fishing practices in stony reef areas and emphasizes the importance of translating the planned management measures into concrete reality.

Additional challenges

At the same time, other human activities compete for the same space, with the planned Princess Elisabeth Zone for offshore wind farms overlapping the Vlaamse Banken Marine Protected Area (Fig. 2) and marine aggregate extraction being prospected at the Northwest site. With respect to the Princess Elisabeth Zone, the EDEN2000 study “Exploring options for a nature-proof Development of offshore wind farms inside a Natura 2000 area”, also coordinated by the MARECO team between 2019 and 2023, provided the necessary knowledge for a nature-proof development of wind farms.

EDEN2000 was commissioned by former Minister for the North Sea Vincent Van Quickenborne and the Department for the Marine Environment of the Federal Public Service Health, Food Chain Safety and Environment. The results serve as advice in the framework of public procurement procedures for the construction of wind turbines under the responsibility of AD Energy of the FPS Economy.


Paul Van Tigchelt, Minister of the North Sea: “Our North Sea is home to more than 2,000 different species. At the same time it is very busy with numerous activities. Our seabed has suffered greatly from intensive fishing. To protect the integrity of the seabed, we have identified the most valuable zones based on scientific research and in consultation with the competent services and the sector, within which we have now proposed fishing measures. We must cherish and support the biodiversity in our North Sea. We must restore nature that has been lost or severely reduced. Such as the European flat oyster and the gravel beds. Belgium has strong ambitions regarding nature restoration and we want to get started on this as quickly as possible.”