Trolling for tuna: speed, distances and how to set the spread

Surface trolling is the simplest way to start fishing tuna from a boat: you cover a lot of water, the lure works on its own and the fish hooks itself. What makes the difference is not the most expensive lure but speed, the position of each lure and the rig. The figures below are a starting point: every boat and every day asks for an adjustment.

Speed: let the lure breathe

For head lures like the Tuna-X, the usual range is 6 to 9 knots. The reference is not the GPS but the lure itself: it should swim a few seconds under the surface leaving a bubble trail, come up to breathe with a spurt and dive again. If it skips and slides, slow down or lengthen the line; if it never surfaces, speed up or shorten it. Into a head sea you usually drop half a knot; with a following sea, add it.

Distances and positions

A simple spread of four or five lines works like this:

• Short corners (the two closest to the stern): on the fifth or sixth wake wave. Here go the largest lures, such as the 31 cm Tuna-X: engine noise does not bother tuna and big fish strike close.
• Long corners: two or three waves further back, with slightly smaller lures.
• Long centre line (the shotgun): far back, in clean water, with the smallest or most discreet lure.

The rule is big close, small far, and no lure should work on the white face of a wave: always look for the back face, where the silhouette shows.

In metres, as a starting reference: centre flat line at 15–18 m, short corners at 20–30 m, long corners at 45–60 m and the shotgun at 75–90 m. After that, your boat's wake decides, not the tape measure.

Rigging

• Leader: hard monofilament or fluorocarbon, 150 to 300 lb depending on the fish you expect, two to four metres long. Thicker is not better: it kills the lure's swim.
• Hook: single inline or double, always with a swivel so the lure turns without twisting the leader. A single hook makes release easier and hooks just as well.
• Drag: to start, about a third of the line's breaking strain. A tuna strike at 8 knots is violent; a hard drag breaks off or pulls the hook.

Colours for water and light

In clear water and sun, natural colours: pearl, blue, sardine. In murky water, low light or at dawn, contrast: dark, gold and orange. Always carry one of each and change the one that is not working, not the whole spread at once.

Mistakes that cost fish

• Speeding up as soon as one strikes: hold course and speed a few seconds so the other lines hook up.
• Lines too close together: they cross on the first turn.
• Not checking the hook after each fish: a bent point does not set.

If you plan to release the fish, read how to do a proper catch and release as well.