Simple lights help fishers catch more shrimp with less damage

Fishing pots are a mainstay for many coastal communities. They are often used to capture shrimp and other crustaceans for the dinner table while keeping habitat damage in check. A new study shows how simple lights can make certain catches bigger.

The findings arrive at a time when many coastal regions are eager for fresh methods that help preserve marine habitats.

“We think that the light attracts zooplankton – like moths around a flame – which in turn attracts shrimp (which eat zooplankton), and that entices larger fish predators into the pots to gobble up the shrimp,” said Dr. Robert Enever from Fishtek Marine.

Lights attract shrimp to pots

Bright beams inside standard pots sound odd. Yet researchers discovered that these small LED devices create a steady draw for zooplankton – tiny sea creatures that float in open water.

Shrimp seem to follow, which then draws in bigger fish on the hunt. Some fishers around the world have tried using conventional bait. Now, these lights could offer a fresh angle by reducing the need for bait while also bringing in a different mix of catch.

Potting for northern shrimp has been around for decades in certain places. According to a study on shrimp pots in the Gulf of Maine, potting can yield multiple pounds of shrimp at a time. That is no small haul.

This new work used pots modified with lights, aiming to see if shrimp counts might rise further. Early signs point to possibilities for bigger yields, but the location of fishing and pot design both matter a lot. Not all areas teem with these shrimp, so trial runs in new spots would be wise.

Bycatch and habitat disturbance

Trawling often means dragging heavy gear across the seabed. That can disturb habitats and risk higher levels of bycatch, which are unintended species snagged in nets.

Study lead author Dr. Tom Horton is an expert in the Centre for Ecology and Conservation at the University ofExeter’s Penryn Campus in Cornwall.

“Shrimp and cod are often fished by trawling, which can result in high bycatch (accidental catching of other species), and habitat disturbance. Finding lower-impact alternatives – including static gear such as pots – is essential for more sustainable fisheries,” said Dr. Horton.

Fish that are drawn to shrimp

Oddly enough, the lights also attracted certain small fish. Some juveniles were caught while chasing shrimp in the pots. That might be a setback if the goal is purely shrimp, or an option for fishers who want to adapt the design to target bigger fish.

Still, the entire concept may provide a path to reduce unwanted catch. Past findings suggest that specialized pots can improve the selection of which fish or crustaceans come onboard. The trick is matching the shape, size, and mesh of the pot to the intended species.

How light affects fish behavior

One striking takeaway from the study is how underwater lighting may trigger an “attraction cascade.” This means a small light draws in plankton, which then brings in shrimp, and finally attracts larger fish that feed on the shrimp.

It’s not just the shrimp that seem curious – gadoid species like poor cod were often found with shrimp in their stomachs, suggesting they were lured in by the buffet.

This pattern changes how we think about baitless fishing. Instead of relying on dead fish or synthetic lures, the pot becomes its own miniature food chain.

But the effectiveness depends on species behavior, water depth, and even how shrimp respond to light at different stages of their life. That makes future testing in other ecosystems all the more important.

Testing pots with LED lights

Future tests are needed before any large-scale rollout. Widespread use of lit pots would call for monitoring of battery use and potential ecological disturbances from extra light. But it could also replace or trim down the use of bait, lowering costs for many fishers.

There is also a chance that these glowing pots might reduce harm to sensitive ocean floors. Instead of dragging big nets, fishers might rely on static gear that has less contact with seabed communities. A switch like that could help keep local ecosystems healthier while still supporting a decent catch.

Towing giant nets for shrimp puts pressure on fuel, labor, and fish populations that get scooped up by accident. Pots with lights might use less bait and damage fewer habitats. But they also need repeated checking, which can become time-consuming.

The future of lit fishing gear

Testing new fishing gear goes beyond science labs. Skippers need to trust that these pots will bring in enough shrimp or fish to cover costs. Balancing gear investment, labor, and local rules can make or break whether lighted gear stays afloat in the long run.

One clear advantage is the simple attraction strategy. If lighting triggers a steady cycle of shrimp and fish, then that changes how pots are used. It might open up new fisheries or reduce side-catches in existing ones.

The study is published in the journal Ocean & Coastal Management.

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