Bait is often viewed simply as a practical tool to attract lobsters and crabs into pots, but new research suggests it plays a far more significant role in coastal marine ecosystems than previously understood.
Scientists from the University of Hull say baited traps may be acting as a substantial and largely unrecorded food input, supporting not only target species but wider crustacean populations as well.
Growing pot fisheries in the UK
Potting – the practice of placing baited traps on the seabed – has expanded rapidly across UK waters in recent decades. It is widely regarded as a low-impact fishing method, particularly because crabs and lobsters are caught alive, and many are returned to the sea.
However, until now, little attention has been given to the ecological footprint of the bait itself.
Unseen consumers of bait
The new study reveals that for every crab or lobster landed, at least 10 more are likely to enter pots but are either too small, female with eggs, or otherwise protected and released.
Many of these animals will have fed on the bait before leaving the pot, while smaller individuals can pass in and out through mesh panels repeatedly. This means bait is effectively subsidising the diet of a much larger portion of the population than previously accounted for.
“The fact that the use of bait can feed many more animals than it aims to capture highlights how there can be wider benefits of crustacean fisheries to the ecosystem when well managed.” – Mike Roach, Deputy Chief Executive of the National Federation of Fishermen’s Organisations (NFFO)
Unrecorded bait input and impact
Crabs and lobsters are highly sensitive to bait scent, which disperses over considerable distances depending on tides and currents. With dense concentrations of pots often deployed in key fishing grounds, large quantities of bait are introduced to the marine environment each year. Despite this scale, bait use in UK pot fisheries is not routinely recorded, leaving a major gap in understanding how fishing activity influences local food webs, behaviour and stock dynamics.
Bait sourcing and ecosystem benefit
Much of the bait used in crustacean fisheries is sourced from waste streams of other sectors, such as surplus mackerel or by-products from farmed salmon. Once deployed, this material does not simply disappear when pots are hauled. Instead, it contributes energy and nutrients to the ecosystem, consumed by both target species and non-target scavengers attracted to the pots.
Management implications for fisheries
Lead author and PhD researcher Nick Rooke describes bait as a missing piece in fisheries management discussions. By quantifying how much bait enters the sea and how many animals are likely feeding on it, the research provides regulators with new, data-driven insight into how pot fisheries function as part of the wider ecosystem. In effect, bait is shaping population dynamics in ways that have not been accounted for.
“This research provides a new piece of the picture which we hope will help shape the long-term sustainability of UK pot fishing. For the first time, we can quantify how bait supports crustacean populations in UK waters.”
Relevance for future fishery plans
These findings are particularly relevant because crab and lobster fisheries are among the first to be included in the UK’s new Fisheries Management Plans. Existing measures – such as bans on landing undersized animals and egg-bearing females – already offer strong protection. The research suggests that bait may further enhance resilience by providing nutritional support to individuals that survive and remain in the ecosystem.
Wider evidence for balanced management
Mike Roach, Deputy Chief Executive of the National Federation of Fishermen’s Organisations (NFFO) and co-author of the study, said the scientific understanding of crab and lobster fisheries has historically lagged behind that of finfish sectors. By highlighting the broader ecological role of bait, the research strengthens the evidence base needed for balanced, effective management.
“This research sheds light on a previously under-studied area and highlights the importance of empirical evidence underpinning fisheries management. The fact that the use of bait can feed many more animals than it aims to capture highlights how there can be wider benefits of crustacean fisheries to the ecosystem when well managed.”
