Shimano Thunnus CI4 – Lightweight Live-Bait Spin Reel with Precision Drag

Seemingly defying the laws of nature, the THUNNUS CI4 merges feather-light handling with stopping power that big fish demand. Shimano borrowed carbon materials from its bicycle technology to craft a body that stays stiff under pressure while remaining light in the hand. The result is a reel that weighs up to seven ounces lighter than the previous model, yet preserves the drive you need for long casts and solid presentations.

Beyond weight, the CI4 carries thoughtful engineering that translates to real-world feel on the water. The HAGANE Gear delivers smooth, durable gearing for confident retrieves, while the Propulsion Line Management System helps keep line where it belongs—on the spool and out of the way. A One-Piece Bail adds stability during line pickup, reducing tangles at critical moments.

Core engineering that powers every cast

• HAGANE Gear: durable, precise gearing for steady retrieves
• Propulsion Line Management System: cleaner line lay and longer casts
• One-Piece Bail: smoother line pickup and reduced tangles

For live bait anglers, presentation is everything. The THUNNUS CI4 introduces new drag systems for the main drag as well as the baitrunner drag, providing nuanced tension control across a range of conditions. This dual-drag setup supports delicate bait presentations when the bite is light and offers reliable stopping power when a big fish surges.

With unmatched adjustability for live bait in varied environments, you can tailor your setup to the moment—without changing reels. The reel is designed to fit into longer sessions, delivering small, controlled actions that add up to a more predictable fishing experience. In practice, you’ll notice smoother stops, cleaner line management, and quicker responses to bites, all while keeping the spool moving consistently under load.

Versatility on the water

Whether you’re chasing inshore species near shore or tackling offshore flats, the CI4 blends light handling with real power. The carbon body resists fatigue during extended runs, and the line management system helps maintain efficient line lay in chop or wind. The combination invites a broader set of live baiting scenarios and fishing styles without switching gear mid-day.

• Lightweight body supports longer days on the water
• Carbon construction resists fatigue under heavy retrieves
• Propulsion line management improves line lay in rough water

In short, SHIMANO’s THUNNUS CI4 offers a compelling package for anglers seeking a nimble live bait setup that can scale with the moment. It’s a thoughtful balance of weight, drag control, and durability that could fit a wide range of trips.