Subsea Commercial Services Ltd.
For anyone already familiar with what eDNA monitoring is and how it works, the next question is usually a practical one: how do you deploy it consistently, in difficult environments, over time? For programmes operating offshore or in locations with limited access, autonomous sampling is increasingly part of the answer. Getting it right requires careful consideration of how, where, and when samples are collected.
Why sampling strategy matters?
eDNA monitoring is only as useful as the data it produces, and the quality of that data depends heavily on how sampling is designed. Frequency, timing, location, and depth all shape what the results can tell you – and what they can’t.
A one-off sample gives you a snapshot. It can be useful, but it can’t tell you whether a species is present seasonally, how populations change over time, or whether a particular event had a measurable effect on the local environment. For those questions, you need repeat sampling collected consistently, at defined intervals, from the same locations.
Getting the strategy right before deployment is also important because eDNA results are sensitive to the conditions in which samples are collected. For example, currents can carry genetic material away from its source, warmer water can speed up degradation and samples taken at the wrong time or depth may not reflect what you’re trying to monitor. Therefore, it’s important to plan eDNA monitoring carefully.
Manual vs autonomous sampling
Manual sampling (collecting water samples by hand, usually from a vessel) is well-established and works well for many applications. It’s straightforward to set up, doesn’t require specialist equipment beyond filtration and storage, and gives you direct control over each sample.
The limitation is access. Offshore sites, remote locations, and environments with unpredictable weather or limited vessel availability make regular manual sampling difficult to sustain. When access is inconsistent, so is the data, and gaps in a time series are hard to recover.
Autonomous sampling systems address this by collecting samples on a programmed schedule without requiring someone to be present each time. Once deployed, they can run across multiple time points, at depth, in locations that would be impractical to visit repeatedly by vessel. They do, however, require more upfront planning and careful deployment to work well.
The right choice depends on the environment, the monitoring objectives, and the programme’s operational constraints.
Deployment considerations
If autonomous sampling is the right fit, several practical factors need to be worked through before deployment.
Repeat sampling
The main advantage of autonomous systems is their ability to collect multiple samples over time from the same location. To make the most of this, sampling intervals need to be chosen with the monitoring objective in mind. Seasonal studies require different timing to baseline surveys or impact assessments. Deciding this upfront and building it into the deployment plan produces far more usable data than adjusting as you go.
Contamination control
Contamination is a major source of error in eDNA work. In a lab setting, protocols are well established. In the field, it’s more complex. Autonomous systems need to be designed and handled to minimise the risk of cross-contamination between samples, and the retrieval process requires the same care as deployment.
Power and retrieval
Autonomous systems deployed for extended periods require sufficient power to complete the sampling schedule, which affects how they are configured and how long they can realistically be left in the water. Retrieval also needs careful planning, particularly in deeper or more exposed locations, where recovering equipment isn’t straightforward.
Harsh and remote environments
Marine environments can be demanding on equipment. Depth, pressure, biofouling, strong currents, and temperature variation all affect how autonomous systems perform over time. Systems intended for offshore or deep-water should be designed with these conditions in mind.
Where autonomous systems are most appropriate
Autonomous eDNA sampling tends to work best where one or more of the following apply:
● The site is remote, offshore, or difficult to access regularly
● The programme requires data across multiple time points or seasons
● Consistency across sampling events is essential to how results will be used
● Vessel availability or weather windows make repeat manual sampling unreliable
Applications across sectors
Autonomous eDNA sampling is used across a range of marine contexts. In ocean science, it supports long-term biodiversity programmes and species distribution research in locations that are difficult to monitor otherwise. In offshore energy, it contributes to environmental monitoring programmes that require consistent, repeatable data over the life of a project. In aquaculture, it can provide regular biological data to support ecosystem awareness alongside other monitoring systems.
Across all of these, the underlying requirement is the same: reliable sampling in variable, limited-access environments.
Thinking about eDNA monitoring for your programme?
If you’re at the stage of working out what eDNA monitoring could look like in practice – whether that’s understanding the options, scoping a deployment, or finding the right equipment – we’re happy to talk through your requirements.