Author: Kelle Moreau

The Weddell Sea is a hotspot of Antarctic life but the impact of climate change and melting of sea ice on the biodiversity and functioning of the ecosystem is poorly known. The new project ‘Weddell Sea Observatory of Biodiversity and Ecosystem Change’ will assess the biodiversity and develop a strategy for monitoring changes in a proposed Marine Protected Area.

The Weddell Sea and Climate Change

The Weddell Sea is the largest marginal sea in the Southern Ocean and a veritable hotspot of life. Here, seals and emperor penguins have their young. The swarms of krill, which graze on microalgae under ice floes, attract fish, whales and seabirds. On the seafloor, millions of icefish spawn, while underwater gardens full of glass sponges, sea anemones and sea squirts thrive, some reaching a level of biodiversity comparable to that of tropical reefs.

“The Weddell Sea constitutes a largely untouched, and therefore extremely valuable, habitat. Not only does it have a high aesthetic value, it is also characterised by unique biodiversity. This biological diversity is also the source of important ecosystem services, like the storage of carbon in the deep sea through ice algae and the remains of plankton sinking to the bottom,” explains Dr Hauke Flores, a marine biologist at the Alfred Wegener Institute (Germany) and coordinator of the Weddell Sea Observatory of Biodiversity and Ecosystem Change (WOBEC) project .

However, climate change has long-since spread to the southern polar region. Hauke Flores adds: “In the past few years, we’ve witnessed an unexpectedly rapid decline in sea ice. We don’t know how, or if, the region’s organisms can adapt to the changed environmental conditions. In order to assess this aspect, we need to first gain a better grasp of the ecosystem’s status quo and urgently need to begin systematic data collection.”

Filling the data gap

The project’s focus is on observing potential long-term changes in biodiversity in the eastern Weddell Sea. Although countries like Germany, Norway and South Africa have been conducting research in the region for decades, systematic studies on its massive ecosystem are lacking. For large parts of the Weddell Sea, long-term observations of the marine biodiversity are even completely non-existent.

To collect valuable new data, an expedition with the German icebreaker Polarstern is planned in the Weddell Sea in 2026, coordinated by the University of Rostock. In addition, the project partners will dig through their archives and make previously unreleased and hard-to-find results available in publicly accessible databases.

Dr Anton Van de Putte of the Institute of Natural Sciences and the Université Libre de Bruxelles is responsible for WOBEC’s data management. He will also be part of the 2026 expedition and will contribute to the processing and interpretation of the data. “On the basis of historical and current data alike, our goal is to create a strategy for long-term environmental monitoring in the Weddell Sea with the aid of autonomous observatories, satellite-based remote sensing, and ship-based sampling,” Anton explains.

A marine protected area?

Stakeholders from the political, business and nature conservation communities will be involved in the process, which will also take place in close collaboration with the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). For many years now, the EU and other CCAMLR members have advocated the protection of large areas of the Weddell Sea. Unfortunately, a previously submitted proposal for a new Marine Protected Area in the Weddell Sea has failed to pass because the vote has to be unanimous and the current geopolitical situation makes CCAMLR negotiations tough.

However, the ratification of the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Treaty) in 2023 is a promising development. It is hoped that this positive signal will stimulate the process of declaring a Marine Protected Area in the Weddell Sea under CCAMLR. WOBEC will provide the opportunity to create a science-based strategy for assessing biodiversity within the Marine Protected Area and its future changes.

 

Eleven institutes from eight countries (Europe and US) have joined forces in the Weddell Sea Observatory of Biodiversity and Ecosystem Change (WOBEC). The project is led by the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI). Over the next three years, participating researchers will determine the current state of the biotic community in the Weddell Sea, as a reference for a long-term monitoring of the ecosystem in the transforming Southern Ocean.

WOBEC is one of 33 projects in the European Union’s flagship programme BiodivMon, under the aegis of Biodiversa+, the European Biodiversity Partnership. The Kick-off Meeting for WOBEC takes place in Bremerhaven, Germany, from 11 to 14 June 2024. National partners have allocated WOBEC 1.9 million euros in financial backing.

The new report ‘Marine mammals and sea turtles in Belgium in 2023’ summarizes the results of the monitoring and research on these animals in Belgium in 2023. Porpoises washed ashore less than in the past 20 years, but high numbers were still counted at sea. Seals continue to increase. The most remarkable marine mammal of 2023 was an Orca, and the stranding of a live Loggerhead Turtle was a Belgian first.

Porpoises and seals

In 2023, 26 Harbour porpoises washed ashore in Belgium. Most of these animals were in an advanced state of decomposition. This was the lowest number of dead porpoises in the past 20 years, continuing the previously documented declining trend. The highest numbers date from a decade ago, when more than 100 porpoises washed ashore in some years (with a maximum of almost 150 in 2013). The reason for the declining number remains subject to speculation.

Aerial surveys of marine mammals in Belgian waters were carried out in April, June and September 2023. The observations allowed to calculate that there were 14,700, 1,400 and 2,500 porpoises present in the research area at these times, respectively. The number in April was one of the highest ever recorded. An extensive analysis of the data collected during aerial surveys in the period 2009-2022 showed that porpoises indeed occur in high densities in the Belgian part of the North Sea, especially in spring. They prefer the northernmost and westernmost parts of our waters, and appear to avoid shipping lanes.

48 dead seals washed ashore in 2023. Further investigation provided information about the cause of death for 14 of these seals. Ten of these probably died in fishing nets. The total number of dead seals washed ashore is comparable to the five previous years (with the exception of a peak in 2021). In the longer term, there is an increasing trend. Sealife cared for seven Grey and 17 Harbour seals in 2023. Almost half of the animals did not make it.

Orca on the border of Koksijde and De Panne

The most striking cetacean of 2023 was undoubtedly the male Orca, which first moved slowly along the coast of Koksijde on October 29, eventually ending up stranded in De Panne. The animal was very thin and weakened, and died almost immediately after stranding. For the time being it could not be determined from which population he came.

It has been since the mid-19th century that strandings of Orcas were recorded in our country. We have tried to unravel the information about those long-ago strandings. We also pay tribute to Louis François Paret, the man to whom we owe the fact that we can still admire the remains of these animals, now more than 175 years old.

Other rare species

A dead Fin whale was brought in on the bow of a ship in the port of Antwerp on August 29, 2023. The autopsy showed that the animal had died as a result of the collision.

Some dolphins, rare for our country, washed ashore in 2023: a Common dolphin on December 22, and two very decomposed Common or Striped dolphins on July 21 and October 8.

Some sea turtles also washed ashore in 2023. A dead Leatherback turtle on October 7 died from traumatic causes. A live beached Loggerhead turtle on November 25 was the first confirmed stranding of this species in Belgium.

The new report ‘Marine mammals and sea turtles in Belgium in 2023’ is published by the Institute of Natural Sciences. The full report and previous annual reports (available since 2014) can be downloaded here (or directly through the following links in Dutch ‘Zeezoogdieren en zeeschildpadden in België in 2023‘ or French ‘Mammifères marins et tortues marines en Belgique en 2023‘).

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.

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.

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.

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.

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.

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

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.

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.

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:

https://biovox.eu/the-ecological-impact-of-offshore-wind-farms-and-sediment-dynamics/

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.

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.

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.

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).

Joint operation on security under the European flag

On May 13^th, 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.

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.

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.

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.

Macrobenthos

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.

Seabirds

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.

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).

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.

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.

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.

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.

Betoncentrale Van den Braembussche has applied on October 31^th, 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).

Application

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, 8^th 2023 until January, 7^th 2024.

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

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

blauwaert@naturalsciences.be