✉︎ info@anguillalight.com
FAQ
Frequently asked questions about AnguillaLight and light-based eel guidance.
1. Why does the European eel need help?
The European eel (Anguilla anguilla) is critically endangered. Since the 1980s, recruitment has declined by more than 90% in many parts of its range.
Every year, silver eel migrating downstream to the sea are killed in turbines, pumps, and sluices. Physical passages, screens, and traps exist — but they are expensive, high-maintenance, and incomplete. At large hydropower intakes, debris and flow make fine screens impossible.
The eel does not need another passage. It needs to be guided.
2. How does light guide eel?
Peer-reviewed research shows that silver eel avoid light and reject illuminated routes when given a choice.
In a controlled study at the University of Southampton, eel were significantly less likely to select a lit channel, and more likely to reject it at higher light intensities.
Vowles, A.S. & Kemp, P.S. (2021). Artificial light at night (ALAN) affects the downstream movement behaviour of the critically endangered European eel, Anguilla anguilla. Environmental Pollution, 274, 116476.
Read the paper →
By tuning wavelength, intensity, pulse rate, and geometry to each site, we create a behavioural barrier that changes eel behaviour at the danger zone.
3. Which light colors and pulse rates work best?
Research shows that blue (480 nm) and white light elicit the strongest avoidance response in silver eel. This matches the eel's retinal sensitivity, which shifts to blue-green as they mature for ocean migration.
For each site, we tune:
- Wavelength — blue, white, and other spectra
- Intensity — strong enough to deflect, tuned to the site
- Pulse rate — constant, strobed, or pulsed patterns
- Geometry — bar, hose, or array, matched to the structure
The exact settings are calibrated per site. No two dams, pumping stations, or intakes behave the same way.
4. Does it work in murky or fast-flowing water?
That is exactly what we test.
Water clarity (turbidity), flow speed, and ambient light all affect how eel respond to a light barrier. Field research at the Iroquois Water Control Dam — a 774-metre-wide channel with flows of 0.6 to 1.5 m/s — confirmed that light affects eel even at high flow.
But the effect was strongest within 25 metres of the light array, with detectable influence to 51 metres. This tells us the light field must be sized to the site.
Our systems are adjustable and calibrated on site, so settings can be tuned to real conditions.
5. Is light guidance safe for other fish and wildlife?
Light is already used in fisheries and fish passage worldwide. Our systems use low-power LEDs, directed and tuned so the light is effective for the target species.
The system creates a behavioural barrier — it does not injure fish or other wildlife.
6. How is the system powered?
Our systems are low power and can be powered by:
- Solar — ideal for remote and off-grid locations
- Grid power — where available
- Hybrid — solar with battery backup for reliability
All systems are submersible, pressure-rated, and built for permanent outdoor installation.
7. Can it be installed at existing infrastructure?
Yes. Our systems are designed to be retrofitted to existing dams, pumping stations, sluices, and hydropower intakes — without major rebuilding.
We handle the full process:
- Manufacture — turnkey permanent and mobile systems
- Install — on site, adapted to existing infrastructure
- Commission — calibrated and tested per location
- Maintain — monitoring, tuning, and service
- Advise — organisations, waterboards, and hydropower operators
8. How long does installation and calibration take?
Installation time depends on the site — structure type, access, flow conditions, and power availability.
As a general guide:
- Small pilot installation: 1–2 days
- Full site installation: 1–2 weeks
- Calibration and validation: 2–4 weeks, depending on eel migration timing
We always begin with a site assessment before proposing a timeline.
9. Do you work outside the Netherlands and Europe?
Yes. Our systems are designed for eel species in Europe, North America, and Australia — including:
- Anguilla anguilla (European eel)
- Anguilla rostrata (American eel)
- Anguilla australis (short-finned eel)
- Anguilla reinhardtii (long-finned eel)
We work with partners across Europe and are expanding internationally.
10. Can light guidance help fish other than eel?
Light affects many migratory fish — but the response is species-specific.
Species that avoid light (can be deflected away from danger):
- Silver eel
- Salmon smolts
- Sea trout smolts
- Shad
- Lamprey
Species attracted to light (a different problem):
- Glass eel and elver
- Sardine, anchovy, mackerel
- Squid
Our systems are tuned for light-avoiding species. We do not claim to protect light-attracted species.
11. How do you prove the system works?
Proof is essential — for water authorities, regulators, and grant programs.
Our approach:
- Partner with universities for independent validation
- Install at pilot sites with real eel migration
- Measure eel behaviour with light on vs. light off
- Publish the results — data, not claims
- Use that data to win the next project
We measure what matters: behavioural response, deflection rate, and survival.
The foundational field study behind our approach is available here:
MacLeod, M.E.C. (2024). Characterizing American Eel Out-Migration and their Vertical Movement Responses to an LED Behavioural Guidance Device. MSc thesis, Carleton University.
Download the full thesis (PDF) →
View the official copy at Carleton University →
Source: MacLeod, M.E.C. (2024), Carleton University. © Michael Edward Cole MacLeod. Used for reference and citation. All rights remain with the author.
12. How can we work with AnguillaLight?
We work with:
- Universities and research institutes — joint research and validation
- Water authorities and river managers — pilot installations and full deployment
- Hydropower operators — turbine and intake protection
- Environmental agencies and grant programs — funded pilot and research projects
If you are working on eel protection, fish passage, or hydropower compliance, we would like to hear from you.
Contact: info@anguillalight.com
13. Does light attract other fish — and can any system protect all species?
Yes, some species — like baitfish, glass eel, and squid — are attracted to light. We don't pretend otherwise.
At pumping stations, sluices, and smaller sites, a physical screen can be installed behind the light barrier to catch what still approaches.
At large hydropower intakes, this is not possible. Flow and debris destroy fine screens, and the turbine overwhelms sound and vibration cues. For light-attracted species at these sites, no current technology provides protection.
Many companies and research groups work on fish protection. Some systems claim to protect all fish species. In practice, no current technology can protect light-attracted species at high-flow hydropower intakes.
We don't claim to solve that problem. Our focus is silver eel and other light-avoiding species, where light guidance genuinely works. We are honest about what we can and cannot do.
AnguillaLight — Guiding eel with light.