Anglers’ Data Stands Up to Scientific Scrutiny

One of the biggest questions about the Sea Angling Diary Project has always been a fair one: can data from a few thousand volunteer anglers really tell us what’s happening across recreational sea angling across England and Wales?

A newly published peer-reviewed study suggests it can.

Researchers have shown that, when analysed using a new statistical approach, anglers’ diary data closely matches the results from traditional national surveys, while providing much more detailed information about when, where and what people are catching throughout the year.

That means every diary entry contributes to an evidence base that is increasingly able to inform fisheries management and demonstrate the importance of recreational sea angling.

“Anglers have always known their catches and their time on the water tell an important story. This research shows that, with the right analysis, those individual diary entries combine to produce evidence that stands up to scientific scrutiny. That gives us much stronger foundations when making the case for recreational sea angling in fisheries management.” said Hannah Rudd, Head of Marine, Angling Trust

Why was this research needed?

Collecting good data on recreational sea angling has never been straightforward.

Unlike commercial fishing, there is no licence or register covering every sea angler, and anglers aren’t required to report what they catch. Instead, we rely on volunteers recording their fishing through the Sea Angling Diary Project.

Scientists also recognised something anglers themselves have pointed out for years: diary volunteers aren’t a perfect cross-section of every sea angler. Some fish every week, some only occasionally. Some target bass, others spend their time chasing cod, rays or flatfish. Some areas have more volunteers than others.

Rather than ignoring those differences, this new research set out to account for them.

A smarter way of analysing the data

The study tested a statistical method called Multilevel Regression and Post-stratification (MRP).

Think of it like this: a diary from a bass angler fishing the Solent doesn’t tell you much about a cod angler fishing off Whitby, and treating every diary entry as interchangeable would blur those differences into a fuzzy average. MRP does the opposite – it adjusts the data so that each entry is weighted according to who’s doing the fishing, where, and how often, building a picture that reflects the real spread of anglers around the country rather than just the ones who happen to log the most trips.

It’s the same kind of technique pollsters use to predict election results from a relatively small sample – and it means the diary data can produce a genuinely representative picture without needing every single sea angler in the country to sign up.

Before publication, the analysis was independently reviewed by experts with no involvement in the project. Feedback from reviewers, the Angling Trust and anglers themselves led to further improvements before the paper was accepted by the journal Fish and Fisheries.

What did the study find?

The results are encouraging.

• Diary data reflects reality. Estimates produced using the new method closely matched those from independent national surveys, showing that the diary data provides a reliable picture of recreational sea angling.
• More detailed information. The approach produces clearer regional and seasonal estimates rather than relying on broad national averages.
• The scale of sea angling. The study estimates that between 577,000 and 745,000 people go sea angling across England and Wales each year.
• Better information for key species. For species such as bass, where recreational catches form an important part of the overall picture, the improved analysis helps track how catches and angler behaviour change over time.

Importantly, no survey is ever perfect. Commercial fisheries data, despite mandatory reporting, also has recognised limitations. Good fisheries management is built by combining multiple sources of evidence, each contributing different pieces of the picture.

Why does this matter?

Some anglers question whether recreational fishing catches are significant compared with commercial fishing.

For many species, commercial landings are indeed much larger. But fisheries management isn’t simply about comparing who catches the most fish.

It’s about understanding who has a stake in the fishery.

Sea angling supports hundreds of thousands of participants, contributes to coastal economies and depends on healthy fish stocks. Managers therefore need reliable information not only about commercial catches, but also about recreational participation, catch trends and how anglers use different fisheries.

For some species, including bass, recreational catches also make up a meaningful proportion of total removals, making good recreational data an important part of the overall evidence base.

Perhaps even more importantly, the diary allows scientists to track changes over time. Consistent data collected year after year helps identify trends in catches, participation and angler behaviour, giving fisheries managers better evidence to judge whether management measures are working and how fisheries are changing.

Turning influence into evidence

When government develops Fisheries Management Plans for species such as bass, wrasse and seabream, it asks what evidence exists.

Without recreational data, decisions inevitably rely much more heavily on commercial information because that’s what’s available.

The Sea Angling Diary Project helps ensure recreational anglers have evidence of their own – and it’s stronger today than it might have been, because the Angling Trust pushed for a re-analysis of the project’s methodology and groundtruthing through Catchwise. That push, and the close collaboration between our organisation and the scientists behind the data, is what led to more robust, more defensible figures – the kind of innovative work that wouldn’t have happened without both sides at the table.

When the Angling Trust responds to consultations, diary data often provides the best available information on how many anglers target a species, what they catch and how important those fisheries are to recreational sea angling. It helps demonstrate that anglers are not simply observers of fisheries – they are stakeholders whose interests should be considered alongside others.

The more anglers who contribute, the stronger and more representative that evidence becomes.

Anglers helping shape the project

The evidence base is also becoming more collaborative.

This month, the new Sea Angling Diary Steering Group meets for the first time, bringing together ten angler representatives from around the country – covering different regions, target species and styles of fishing, from shore anglers to charter skippers.

The group won’t just be consulted after the fact. They’ll have a direct say in how diary data is collected (including what’s being asked and how easy it is to log a trip), how it’s interpreted, and how it’s used when the Angling Trust and scientists make the case to government. That means the anglers who actually generate this evidence will help decide how their own data gets read and applied – making sure the project keeps pace with what’s really happening on the water, rather than drifting away from it over time.

Fish. Log. Influence.

Every diary entry adds another piece to the picture.

No single fishing trip changes fisheries management on its own, but thousands of trips recorded over many years create something much more powerful: credible evidence that shows where anglers fish, what they catch, how fisheries are changing and why recreational sea angling deserves a place in decisions about our seas.

If you aren’t already part of the Sea Angling Diary Project, now is a great time to get involved.

Sign up today: https://seaangling.org/tool/signup

Search the library here to see the existing data: https://rconnect.cefas.co.uk/sea_angling_library/