What trolling means on the Bornholm grounds

Trolling around Bornholm is not casting and retrieving from a boat—it is towing a baited line or lure behind a moving vessel to cover water and find fish that are spread across the seabed or suspended in the water column. The technique works because mackerel, cod, and sea trout move with currents and temperature shifts, and a slow-moving boat lets you fish a larger area than you could from a stationary position. Bornholm's rocky reefs, deep channels, and the meeting point of the Baltic and North Sea waters create conditions where trolling catches fish consistently, especially in spring and autumn when mackerel migrate through the region.

The method is old on these grounds. Bornholm fishers have trolled for centuries, and the practice remains central to how recreational anglers and small-boat operators fish the waters around the island. You will see it practiced from small open boats, cabin cruisers, and traditional wooden vessels, all working the same principle: move slowly, keep the line in the water, and let the fish come to you.

Key Takeaways

  • Trolling around Bornholm targets mackerel, cod, and sea trout by towing baited lines or lures behind a moving boat at speeds between 2 and 4 knots.
  • The rocky reefs and deep channels around the island—particularly the Christiansø grounds and the waters east of Nexø—hold fish year-round but are most productive in spring and autumn.
  • Mackerel trolling uses small spinners or feathered lures and requires lighter tackle, while cod trolling demands heavier lines and larger baits or shads to reach the seabed.
  • Local knowledge of tide, current direction, and seasonal temperature changes determines where fish hold and how fast you should move the boat.
  • Bornholm's fishing community shares information through harbours, tackle shops, and informal networks that tell you which grounds are producing and which techniques are working this week.

The grounds around Bornholm and what lives there

Bornholm sits at a crossroads of water masses. The Baltic Sea's fresher, cooler water meets the saltier Atlantic influence, and this boundary creates feeding zones where fish concentrate. The rocky reefs that ring the island—particularly around Christiansø to the north and the grounds east of Nexø—hold cod year-round. Mackerel arrive in spring, peak in early summer, and return again in autumn on their migration routes. Sea trout move through the shallower waters closer to shore, especially in spring and early autumn.

The seabed matters. Bornholm's reefs and rocky outcrops create shelter and feeding habitat. Trolling lets you work these features without snagging constantly—you move slowly enough to feel the bottom and adjust your depth, but fast enough to cover ground and trigger strikes. The deeper channels between reefs hold larger cod and sometimes ling. The shallower rocky areas, 15 to 30 metres down, hold mackerel and smaller cod.

Water temperature shifts the bite. In spring, as the water warms from winter cold, fish move shallower and feed more aggressively. By midsummer, the thermocline—a sharp temperature boundary—forms, and fish hold below it. Autumn cooling brings another active period. Winter fishing is possible but slower, and many recreational boats do not operate in the coldest months.

Tackle and lures for mackerel trolling

Mackerel trolling on Bornholm uses light tackle because the fish are not large—most run 300 to 600 grams—and they respond to small, fast-moving lures. A spinning rod of 6 to 7 feet with a multiplier reel holding 200 metres of 0.20 to 0.25 millimetre monofilament or braided line is standard. The lighter line lets the lure work naturally and gives you better feel for the bottom and for strikes.

Lures are small and bright. Feathered traces—a rig of four to six small hooks dressed with coloured feathers or synthetic hair—are traditional and still effective. They mimic a small baitfish school and can catch multiple fish on a single strike. Spinners in sizes 1 to 3, particularly those with silver or copper blades, work well. Some anglers use small shads—soft plastic lures 5 to 8 centimetres long—rigged on light jig heads. The key is movement: mackerel want a lure that darts and flashes, so you troll at 3 to 4 knots to keep the lure active.

Colour matters less than action, but silver, copper, and red-and-white combinations have long track records. Local tackle shops in Rønne and Nexø stock proven patterns, and asking what is working this week is worth the conversation—tackle shop staff know what the boats brought in yesterday.

Tackle and technique for cod trolling

Cod trolling demands heavier gear because you are working deeper water and larger fish. A boat rod of 6 to 7 feet with a multiplier reel and 0.30 to 0.40 millimetre monofilament or braided line is typical. The heavier line handles the depth and the weight you need to reach the seabed, and it gives you the backbone to turn a large cod away from rocks.

Baits and lures are larger. Fresh mackerel or herring fillet, rigged on a single or double hook, is traditional and effective. Many anglers use pirks—metal lures shaped like small fish, weighing 150 to 300 grams—which flutter as they sink and can be worked with a slight lift-and-drop motion while trolling. Larger shads, 12 to 15 centimetres, rigged on heavy jig heads also work. The weight must be enough to keep the lure near the seabed, where cod hunt.

Trolling speed for cod is slower than for mackerel: 1.5 to 2.5 knots. This slower pace lets the lure work deeper and gives cod time to react. You feel the bottom regularly—a slight tick or drag—and adjust your depth to stay just above the rocks. When you feel a strike, set the hook firmly and keep the rod tip up to prevent the fish from running into cover.

Reading the water and timing the tide

Bornholm's tides are modest—the range is typically 0.5 to 1 metre—but the currents they create are strong and predictable. Slack water, the period around high and low tide when current is weakest, is often slower for fishing because fish are less active. The hour or two before and after slack, when current is running, is usually more productive. Local tide tables, available at harbours and online, show the timing for each day.

Current direction matters. Fish face into the current to feed, so they hold on the upstream side of reefs and rocky outcrops. If you know the current is running north, you troll from south to north, moving with the current and letting your lure drift naturally into the feeding zone. Trolling against the current is slower and less effective, though it can work in shallow water where fish are less current-sensitive.

Water colour tells you about visibility and feeding activity. Clear water, common in spring and autumn, means fish can see your lure from farther away, so you can use smaller lures and lighter tackle. Cloudy or greenish water, which happens after storms or during algal blooms, means fish rely more on vibration and smell, so larger lures and brighter colours help. Local anglers adjust their approach based on what they see when they leave the harbour.

Where to troll and how to find fish

The Christiansø grounds, north of Bornholm, are famous for large cod. The rocky reefs create a complex seabed, and fish hold in the gullies and around the rocks. Trolling here requires attention to your depth sounder and a willingness to adjust your line constantly as the bottom rises and falls. The reward is consistent fishing and the chance at fish over 5 kilograms.

The Nexø grounds, east of the main island, hold mackerel in spring and autumn and cod year-round. The water is slightly shallower here, 20 to 40 metres, and the seabed is less dramatic than Christiansø, so trolling is easier for less experienced boat handlers. This is a good starting ground if you are new to Bornholm trolling.

The western side of Bornholm, facing Sweden, has productive grounds around Hasle and Rønne. These waters are slightly warmer and hold sea trout and mackerel in season. The seabed is mixed—some rocky areas, some sand—so fish are more scattered, but the fishing can be excellent in spring and early autumn.

A depth sounder is essential. It shows you the seabed shape, the depth of the thermocline, and sometimes the fish themselves as marks on the screen. Learning to read your sounder—to recognize a rocky reef, a sand patch, or a school of mackerel—takes practice, but it is the difference between trolling blindly and fishing with purpose. Many charter boats and experienced anglers will show you how to use one if you ask.

Seasonal patterns and when to go

Spring, from April through May, brings the first mackerel run and active cod feeding as water temperature rises. The days are long, the weather is often stable, and the fishing is consistent. This is the busiest season for recreational boats, and the harbours fill with anglers.

Summer, June through August, is warm and calm, but the fishing often slows as fish move deeper and the thermocline forms. Many anglers take a break or fish early morning and late evening when the surface cools. Some boats troll at night when mackerel feed more actively.

Autumn, September through October, brings the second mackerel migration and renewed cod activity as water cools. The fishing rivals spring, and the weather is often clearer. This is considered by many local anglers to be the best season for consistent results.

Winter, November through February, is cold and rough. Fishing continues, but fewer recreational boats operate, and the catch is slower. Some dedicated anglers fish winter for the solitude and the chance at large cod, but it requires experience and proper safety equipment.

Learning from the Bornholm fishing community

The harbours at Rønne, Nexø, and Svaneke are working fishing communities where you can watch boats come in, see what they caught, and talk to skippers about what is working. This informal knowledge—what ground produced today, what lure caught fish, which tide was best—is more current than any guide. Tackle shops in these towns stock local patterns and know the week's fishing.

Charter boats operate from Bornholm's harbours and take recreational anglers trolling. A day on a charter is an investment, but you learn the grounds, the technique, and the local patterns from someone who fishes these waters regularly. Many charter skippers are generous with knowledge and will explain why they chose a particular ground or lure.

Fishing clubs and local associations sometimes organize trips or social events. These are good places to meet other anglers, ask questions, and find out about upcoming conditions or changes in the fishing.

Frequently Asked Questions

What is the difference between trolling and trawling?

Trolling is recreational fishing—you tow one or a few lines behind a boat to catch fish for eating or sport. Trawling is commercial fishing with large nets. Bornholm has a strong trawling fleet, but recreational trolling is a separate activity with different boats, gear, and regulations.

Do I need a fishing license to troll around Bornholm?

Denmark requires a fishing license for most recreational fishing in Danish waters. The rules and costs vary, so check with the Danish Nature Agency or a local harbour office before you fish. Charter boats typically include the license in their fee.

What is the best time of day to troll?

Early morning and late evening often produce better than midday, especially in summer when the sun is high and the water is warm. Overcast days can be good all day. Tide timing matters more than time of day—fish feed most actively during running tide, regardless of whether it is morning or afternoon.

Can I troll from a small boat or kayak?

Trolling works best from a boat you can control at slow speed and that has enough freeboard to handle the water safely. Small open boats of 5 to 7 metres are common on Bornholm. Kayaks are not suitable for trolling in these waters—the currents are strong, the water is cold, and you need a boat you can manoeuvre quickly if something goes wrong.

What do I do if I hook a large fish and it runs toward rocks?

Keep the rod tip up and apply steady pressure to turn the fish away from cover. Do not jerk or try to force it—that risks breaking the line. If the fish reaches rocks and you feel it rubbing the line, lower the rod tip slightly to ease pressure, then raise it again to regain control. Experience teaches you the balance between pressure and patience. Watching experienced anglers handle large fish is the best way to learn.