Key Takeaways:
- Marine Net Gain (MNG) is the aquatic counterpart of Biodiversity Net Gain (BNG).
- Marine Biodiversity Net Gain is a crucial next step in policy development for nature recovery across English waters.
- The government’s 2023 response confirmed its support for Marine Net Gain, but outlined that there’s more work needed in the delivery and metric.
- Until the government releases the draft metric and pilot programme, MNG remains in development, but the direction of travel is clear.
- Not about ecologically improving the entire English sea, MNG is about offsetting the damage from habitats physically impacted by specific marine activities.
- Developers must first avoid and mitigate harm, then remaining impacts require the developer to fund projects delivering measurable impacts with ecologically relevant gains.
Marine Biodiversity Net Gain is a crucial next step in policy development for nature recovery in the waters, now more than ever in a time of immense offshore wind demand.
With pressures from climate change, development and fisheries increasing, attention is shifting to how marine ecosystems, habitats and species can deliver long term environmental benefits.
Marine Net Gain will strengthen marine conservation through targeted strategic interventions and active interventions protecting both our natural environment and marine protected areas.
What is Marine Biodiversity Net Gain?
Marine Net Gain (MNG) is the aquatic counterpart of Biodiversity Net Gain (BNG).
A couple of years into its implementation, BNG has a massive £1.2 billion pounds worth of BNG units on the Gaia BNG Marketplace alone.
The policy kick-started nature finance at a rapid scale, with the help of landowners, environmental organisations, charities, developers and ecologists making the biodiversity gains happen in real time.
While BNG is now delivering measurable outcomes for England’s nature, Marine Net Gain is at the very forefront of its journey.
Extending net gain into marine life first considered in 2019, until a formal consultation was launched in 2022 and collected views on how the policy could work for 14 weeks.
The government’s 2023 response confirmed its support for Marine Net Gain, but outlined that there’s more work needed in the delivery and metric.
Until the government releases the draft metric and pilot programme, MNG remains in development, but the direction of travel is clear. The sector is waiting for the next formal step before MNG can move from concept to reality.
Why Marine Net Gain Matters
Biodiversity Net Gain covers land and the intertidal zone through Area, Hedgerow and Watercourse habitats.
While BNG applies down to the mean low water mark, MNG would begin seaward of this, applying to developments across English inshore and offshore waters.
Not about ecologically improving the entire English sea, MNG is about offsetting the damage from habitats physically impacted by specific marine activities.
Think offshore wind farms, subsea cable installation, dredging, port works, jetties, coastal defence schemes and more – all harmful to marine life and ecosystems.
Marine developments’ current regulations attempt to avoid and minimise harm, but MNG matters because it will deliver a crucial gain and actively improve the state of the environment.
It matters because half of our nature is at sea, and offshore industries are about to explode and either double or triple to accommodate the green transition. Without net gain locked in, it could be detrimental to UK marine nature.
Now that BNG has been tried and tested, it’s time to get the MNG policy underway so that new infrastructure can be built to accommodate decarbonisation without sacrificing crucial habitats.
How Marine Biodiversity Net Gain Is Measured
While we have no final metric, Defra’s 2023 consultation response outlines the specifics of how MNG could be measured.
They state they ‘intend for MNG to operate alongside existing (…) environmental assessments’ (Defra, 2023). From this, we can hypothesize how MNG might work in practice.
Baseline Marine Assessments
Environmental Impact Assessments, Habitats Regulations Assessments and Marine Protected Area assessments all require the baseline habitat and species data.
This is to capture the exact ecological condition of the habitats and wildlife before any human activity has directly impacted it, crucial to ultimately achieving the net gain from the starting point.
In BNG, baseline methods involve field surveys and habitat mopping, whereas marine methods could involve benthic sampling, acoustic surveys and remote sensing.
Key Marine Indicators
Key marine indicators come from existing EIA and HRA practice. They indicate the status of a marine habitat, and whether it’s in decline, stable, or improving.
This involves the area or condition of seabed habitats, the presence of species, clarity of water, and signs of habitat connectivity or recovery.
Methods involve a range of marine surveys from sonar mapping to seabed sampling, and after the baseline search for indicators, surveys will be rerun throughout the development works, plus years after to track the mandated improvement.
Tools And Methodologies
Without an MNG metric, tools and methods can be drawn from existing EIA and HRA practices in line with the policy’s principles.
What’s most likely to enter the MNG toolkit is habitat mapping (location), condition assessments (ecological status), habitat-based scoring (simple at first, i.e. improvement over time), and repeat survey monitoring.
Monitoring And Reporting Requirements
In MNG, habitats impacted by developments are monitored through developer funded surveys, with regulators reviewing results to track how much damage has taken place.
The length of monitoring could be set case by case depending on the project details.
Developers must first avoid and mitigate harm, then remaining impacts require the developer to fund projects delivering measurable impacts with ecologically relevant gains.
With reporting, developers must submit their monitoring data to regulators to prove compliant delivery.
Key Principles Of Marine Biodiversity Net Gain
The key principles of Marine Net Gain are:
- Leaving England’s marine environment in a measurably better state
- Site-level interventions, strategic elsewhere interventions, and pressure reduction measures are allowed
- Working alongside EIAs and HRAs, not replacing or weakening them
- Contributions-based approaches could allow multi-funding into large-scale projects
- Assessing species as well as habitat, not just habitat alone
- Following the mitigation hierarchy of avoid, mitigate, and address impacts.
Structured to deliver a policy that improves marine biodiversity on a major scale, the principles will guide the subsequent tools, policies and frameworks that turn MNG into a tangible means for action.
Legislation And Policy Framework
Legislation for MNG is needed now more than ever. Demand for offshore wind is surging immensely, as the technology is there, and the sea offers space that the land doesn’t.
So why can’t the law catch up?
Marine habitats’ fluidity, complexity, and movement make their science much harder to standardise through one singular framework.
Scientists are testing methods on how to reliably measure change in such a dynamic, complex environment, without risking committing to a policy that could go wrong.
Marine Net Gain Versus Terrestrial Net Gain
Biodiversity Net Gain has now been mandatory in England for almost 2 years, with leading BNG platform Gaia’s BNG Marketplace having acquired over £1.2 billion worth of BNG units.
Marine Net Gain, in turn, is still much under development, with government work on the policy kept behind closed doors.
With BNG still in its piloting stage, revealing what works and what doesn’t for England’s first net gain nature policy, the government has time to get the delivery, science and metrics right.
A stark difference between BNG and MNG is that while terrestrial habitats are stationary, marine habitats move. Sediment shifts with tides, species migrate seasonally, and seabed features change shape.
To deal with this, broader habitat-based assessments will be used within adaptive management instead of static, rigid locations and boundaries.
Another key difference is that in Biodiversity Net Gain, developers must purchase BNG units within either their National Character Area (NCA) or Local Planning Authority (LPA). This restores nature close to the original habitat, with penalties for the further away you buy the units.
MNG will involve a much different approach. Developer contributions could instead be pooled together to contribute to larger marine projects with measurable outcomes for marine biodiversity (think large-scale seagrass restoration, kelp forest creations, salt marshes and more).
Challenges In Delivering Marine Biodiversity Net Gain
Risks And Mitigation Measures
A risk is the poor ecological connection between the habitats impacted and the far-off projects being funded into as a means of offsetting.
To mitigate this, expert ecological advice, regional marine plans, and well-evidenced habitat types must be utilised.
Another pressing risk is that the project being funded into does not deliver the gains it’s set out to deliver. Projects must be managed suitably with effective designs built for dynamic, complex habitats.
Stakeholder Roles
There are various stakeholders involved, such as Defra setting policy direction, the Marine Management Organisation issuing marine licences, nature bodies advising on ecology, developers minimising harm, and scientists carrying out surveys.
Opportunities And Benefits
Marine Net Gain could truly unlock a sea of benefits. It’s charging developers who are directly harming the marine enviornment, and putting their money into large-scale marine restoration projects.
Due to this approach, these projects would have the funding to go above and beyond minor, small-scale individual recoveries.
This opens many opportunities, starting with more animals. More fish, shellfish, sharks, seabirds, rays, and marine mammals could recover from their quiet declines in recent decades.
Lost habitats could be returned, with oyster reefs, kelp forests and seagrass having been hammered for decades. Large projects could unlock their restoration at scale, not just fractions and pockets.
Waters can be clearer and cleaner, visibility healthier with less algal blooms and murky waters.
Crucially, our oceans would be more resilient to our unavoidable climate pressures, making MNG not only a responsible next step for the UK government, but essential for the livelihoods of our coastal communities, fisheries and marine industries that depend on healthy, functioning seas.
Marine Habitat Types Affected
Marine Net Gain mainly affects habitats that get physically disturbed by development, like seabed sands and muds, reefs, seagrass meadows, kelp forests, saltmarsh, intertidal flats and estuaries.
Supporting food webs, carbon storage and coastal protection, it’s crucial to keep them protected from harm and offset damage to a net gain when it has been done.
Examples Of Marine Net Gain In Practice
While there aren’t formal MNG schemes yet, relevant examples already exist.
This includes projects such as seagrass restoration in the Solent, native oyster reef creation through the Solent Oyster Restoration Project, and nature inclusive offshore wind foundations tested in the Dutch North Sea.
The Role of Marine Net Gain in Offshore Wind Projects
As demand for offshore wind explodes, MNG’s enforcement is crucial and should be expedited.
In a pre-MNG world, developers are currently drilling deep into England’s seabeds to make room for turbines, lay cables, and disturbing sediment.
Developers are required to limit damage and, in some cases, compensate for impacts, but they aren’t required to deliver a net gain for nature.
Less sensitive locations are chosen and works are timed to avoid breeding seasons, but developers aren’t required to actively improve marine biodiversity.
MNG would shift this from managed decline to measurable recovery.
Future Outlook
The future outlook of Marine Net Gain is that it’s still early, and we are way off from anything mandatory.
With the BNG system successfully showcasing that environmental net gains can work, MNG appears hopeful, but dynamic marine environments require even more complicated frameworks to be successful.
MNG feels inevitable, but the sector wants it built properly, not rushed into failure.
More Information
https://www.gov.uk/government/consultations/consultation-on-the-principles-of-marine-net-gain
FAQs
What is Marine Biodiversity Net Gain?
Marine Net Gain (MNG) is the aquatic counterpart of Biodiversity Net Gain (BNG).
When was Marine Net Gain first considered?
Extending net gain into marine life first got considered in 2019, until a formal consultation launched in 2022 and collected views on how the policy could work for 14 weeks.
Is Marine Net Gain mandatory yet?
Until the government releases the draft metric and pilot programme, MNG remains in development, but the direction of travel is clear.
What types of activities does Marine Net Gain affect?
Think offshore wind farms, subsea cable installation, dredging, port works, jetties, coastal defence schemes and more – all harmful to marine life and ecosystems.
Who is responsible for delivering Marine Net Gain?
Developers must first avoid and mitigate harm, then remaining impacts require the developer to fund projects delivering measurable impacts with ecologically relevant gains.