What Is Longline Fishing: A Guide to the Technique

Table of Contents

1. Introduction
2. Defining Longline Fishing
3. The Mechanics of the Longline
4. Pelagic vs. Demersal Longlining
5. Applying Longline Principles to Survival: The Trotline
6. Gear Considerations for Effective Longlining
7. Environmental Impact and Bycatch
8. Advanced Longline Technology
9. Why Understanding Longline Fishing Matters
10. Conclusion
11. FAQ

Introduction

When you are deep in the backcountry or managing a long-term remote camp, food procurement becomes a matter of caloric efficiency. You quickly realize that standing on a bank with a rod and reel for six hours is a luxury that your schedule might not allow. This is where passive fishing techniques—methods that work while you sleep, forage, or build shelter—become invaluable. At BattlBox, we focus on gear and skills that maximize your effectiveness in the wild, and getting expert-curated gear delivered monthly is a prime example of high-efficiency resource gathering. While typically known as a large-scale commercial method, the mechanics of the longline can be scaled down into a highly effective survival tool. This article covers the mechanics of longline fishing, the different types used at sea, and how you can apply these professional principles to your own self-reliance strategies.

Defining Longline Fishing

Longline fishing is a commercial fishing technique that uses a single, long main line to which many shorter branch lines are attached. These branch lines, known as snoods or gangions, end in baited hooks. Depending on the target species and the scale of the operation, a single longline can stretch for miles and hold hundreds or even thousands of hooks. This method is designed for efficiency, allowing a crew to cover a massive area of the ocean without the need for constant active monitoring of every individual line.

In the world of professional fishing, this technique is used to catch high-value pelagic fish like tuna and swordfish, as well as bottom-dwelling species like halibut and cod. The main line is deployed from a vessel, allowed to "soak" for several hours, and then hauled back in using hydraulic winches. Because the gear is designed to be left unattended for periods, it is a form of passive fishing.

For the outdoor enthusiast, the longline represents the pinnacle of "set it and forget it" food procurement. When we talk about survival fishing or primitive bushcraft, we often refer to "trotlines" or "limblines." These are essentially small-scale longlines adapted for freshwater rivers or coastal estuaries, and BattlBox's Fishing Collection is a practical place to start.

Quick Answer: Longline fishing is a passive commercial fishing method using a long main line with numerous baited branch lines called snoods. It allows fishermen to target specific species across vast distances, either near the surface or along the ocean floor.

The Mechanics of the Longline

To understand how this system works, you have to look at the individual components. A longline is not just a heavy rope with hooks; it is a carefully engineered system designed to withstand the tension of the sea and the weight of large, powerful fish.

The Main Line

The main line is the "backbone" of the entire operation. In commercial settings, this is often made of high-test monofilament or braided nylon. It must be strong enough to support the weight of the entire catch and the drag of the water. For a survivalist, your main line might be a length of #36 tarred bank line or heavy-duty paracord, depending on the environment, or a compact utility rope like Rapid Rope.

Snoods or Gangions

These are the shorter lines that branch off from the main line. They are attached at regular intervals to prevent the hooks from tangling with one another. A swivel is almost always used at the attachment point. This is critical because a hooked fish will often spin or thrash; without a swivel, the fish would twist the snood around the main line, potentially snapping the cord or tangling the entire rig. If you want a deeper look at rope handling, How to Tie a Prusik Knot is a useful next step.

The Hooks

The choice of hook depends entirely on the target. In longlining, circle hooks are the industry standard. Unlike traditional J-hooks, circle hooks are designed to slide to the corner of the fish’s mouth before setting. This is safer for the fish if they are to be released and more effective for passive fishing because the fish essentially "sets" the hook themselves as they swim away. For compact, ready-to-go fishing support, Exotac xREEL keeps the essentials together.

Buoys and Weights

Depending on where the fish live, the line needs to be suspended at a specific depth. Buoys provide flotation for surface-level fishing, while heavy anchors or lead weights are used to drop the line to the bottom. Each buoy often features a flag or a radio transponder so the vessel can locate the line after it has drifted with the current.

Pelagic vs. Demersal Longlining

Longlining is generally divided into two main categories based on where the line sits in the water column. Knowing the difference is key to understanding how professional fleets operate and how you should scout your own fishing spots.

Pelagic Longlining

Pelagic longlining targets fish that live in the open ocean, away from the bottom. These are typically "blue water" species like Yellowfin Tuna, Bigeye Tuna, and Swordfish.

• Position: The line is kept near the surface or at mid-water depths using a series of buoys.
• Length: These lines can be exceptionally long, sometimes exceeding 30 miles in length.
• Movement: The line is often allowed to drift freely with the ocean currents rather than being anchored to the sea floor.

Demersal Longlining

Demersal longlining targets species that live on or near the ocean floor, such as Atlantic Cod, Halibut, and various types of Grouper.

• Position: The main line is weighted so that it sits directly on or just above the seabed.
• Anchoring: Unlike the drifting pelagic lines, demersal lines are usually anchored at both ends to keep them in a specific geographic location.
• Environment: This method is often used over rocky reefs or continental shelves where these species congregate. For a broader look at responsibility in the water, Embracing Sustainable Fishing goes deeper on the environmental side.

Key Takeaway: Pelagic longlining drifts in the open water to catch fast-moving predators, while demersal longlining stays anchored to the bottom to catch reef and floor-dwelling fish.

Applying Longline Principles to Survival: The Trotline

While most of us will never operate a 30-mile commercial longline, the principles remain the same for survival fishing. In a survival situation, your goal is to obtain the most protein for the least amount of energy spent. A "trotline" is essentially a scaled-down longline used in freshwater or coastal areas, and BattlBox's Emergency / Disaster Preparedness Collection is packed with the kind of kit-first thinking that fits this mindset.

How to Build a Basic Trotline

To build a functional trotline, you need a few basic supplies that we often include in our survival and emergency kits.

1. Main Line: A 50-to-100-foot length of tarred bank line is ideal. It’s abrasion-resistant and holds knots well.
2. Drops (Snoods): 12-to-18-inch lengths of lighter line.
3. Hooks: Size 1/0 or 2/0 hooks are versatile enough for most freshwater fish.
4. Weights: Large river stones or lead sinkers to keep the line submerged.

Step 1: Choose Your Location. Look for an area where fish travel, such as the mouth of a creek, a deep bend in a river, or a transition zone between shallow and deep water.

Step 2: Anchor the Ends. Tie one end of your main line to a sturdy "stump" or a heavy rock on the bank. Run the line out across the water, anchoring the other end to a submerged log or another heavy weight.

Step 3: Attach the Drops. Using a Prusik knot or a simple loop, attach your snoods to the main line every 5 to 10 feet. Ensure the drops are shorter than the distance between them so the hooks don't tangle with each other.

Step 4: Bait and Set. Bait your hooks with whatever is local—worms, crawfish, or small baitfish. Sink the line so it isn't visible from the surface to avoid theft or spooking the fish.

Step 5: Check Regularly. While this is a passive method, you should check the line at least twice a day. Leaving fish on the line too long can attract predators like turtles or alligators, which will steal your catch and ruin your gear.

Bottom line: A trotline is a survivalist’s version of a longline, allowing you to manage multiple hooks simultaneously and increase your chances of a successful harvest.

Gear Considerations for Effective Longlining

Whether you are looking at the professional industry or building a kit for your bug-out bag, the quality of your gear determines your success. At BattlBox, we emphasize gear that performs under pressure, and our EDC Collection reflects that mindset.

Line Strength and Visibility

In commercial longlining, the main line needs to be incredibly strong to pull in a 200-pound tuna while the boat is moving. In a survival context, you want a line that is strong but also low-visibility or naturally colored. Tarred bank line is a favorite among woodsmen because it is dark, sinks naturally, and resists rot better than standard nylon. A compact field tool like Olight Oclip Light with Red and White Light can help keep hands free when you are working after dark.

Swivels: The Unsung Heroes

The swivel is the most important hardware in any multi-hook system. When a fish is caught, it will fight. If your snood is tied directly to the main line without a swivel, the fish’s movement will create kinks and knots. High-quality barrel swivels or crane swivels allow the drop line to rotate 360 degrees, keeping the main line straight and functional.

Hook Selection

We mentioned circle hooks earlier. They are the "gold standard" for a reason. Because you aren't there to "set" the hook when the fish bites, you need a hook shape that does the work for you. A circle hook’s point is turned inward. When the fish swallows the bait and swims away, the hook slides out of the throat and catches in the jaw. This results in a more secure "hook-up" and makes it much easier to remove the hook later. If you want to compare passive setups with a more active approach, How to Use Lure Fishing is a useful next read.

Bait Preservation

In a commercial setting, bait is often frozen squid or mackerel. In the wild, you have to be more creative. Using "stink baits" or cured meats can work well for catfish, but for most species, live or fresh-killed bait is best. If you are setting a line for the night, ensure your bait is secured tightly so it isn't easily stripped by smaller, non-target fish.

Environmental Impact and Bycatch

One of the most discussed aspects of longline fishing is its impact on the environment, specifically bycatch. Bycatch refers to the accidental capture of non-target species. Because longlines can stay in the water for many hours and cover vast distances, they sometimes catch sea turtles, sharks, and even seabirds like albatrosses that dive for the baited hooks as the line is being deployed.

Solutions in the Industry

The fishing industry has developed several ways to mitigate these issues:

• Circle Hooks: As noted, these are less likely to be swallowed deeply, making it easier to release bycatch alive.
• Weighted Lines: Deploying lines faster and deeper helps them sink past the range where seabirds can reach the bait.
• Acoustic Pingers: Some fleets use devices that emit sounds to warn off dolphins and whales.
• Night Setting: Setting lines at night reduces the chances of catching birds that hunt by sight during the day.

Ethics for the Outdoorsman

When you use longline principles in the wild—like setting a trotline—you have a responsibility to be ethical.

• Check the laws: Many states have very specific rules about the number of hooks you can use and how the line must be tagged with your name and info.
• Don't "Ghost" Fish: Never leave a line in the water if you are leaving the area. Lost lines continue to catch and kill fish indefinitely, a process known as "ghost fishing."
• Target what you need: Only set as many hooks as you need to feed yourself or your group.

Note: Always check your local Department of Natural Resources (DNR) or Fish and Wildlife regulations before setting a trotline or any multi-hook rig. Regulations vary wildly between states and water bodies.

Advanced Longline Technology

Modern commercial longlining has come a long way from simple ropes and hooks. Today, technology plays a massive role in how these fleets operate efficiently.

Hydraulic Haulers

Pulling in miles of line by hand is impossible. Modern vessels use hydraulic drum haulers that can spool and unspool miles of high-test line in a fraction of the time. This allows ships to stay out longer and manage more gear.

GPS and Satellite Tracking

Each end of a longline is usually marked with a buoy equipped with a GPS transmitter. The ship’s captain can track the movement of the line in real-time on a computer screen. This is vital because ocean currents can move a line several miles from its original deployment point.

Depth Sensors

Some advanced setups use "hook timers" or depth sensors. These devices record exactly when a fish hits the hook and at what depth. This data allows fishermen to adjust their next set to target the most productive water temperatures or depths.

Why Understanding Longline Fishing Matters

You might wonder why a survivalist or a camper needs to know about industrial fishing. The reason is simple: scale and efficiency. The history of survival is the history of humans taking industrial concepts and simplifying them for the field. If you want a second fishing perspective to compare against passive setups, How to Use Lure Fishing is a solid companion piece.

By understanding how a 50-mile tuna line works, you understand the importance of swivels, the mechanics of circle hooks, and the necessity of proper anchoring. You learn that the "backbone" of a system must be stronger than the "branches." You learn that the depth of your bait is more important than the amount of bait you use.

At BattlBox, we curate gear that allows you to apply these types of professional-grade principles on a personal level. Whether it is providing you with the highest quality paracord for a main line or the right cutting tools to prep your bait, we want you to have the same confidence in your gear that a commercial sea captain has in his. The lessons in The Survival 13 line up with that same priorities-first approach.

Key Takeaway: The principles of longline fishing—tension, passive capture, and depth control—are the foundations of successful food procurement in any environment.

Conclusion

Longline fishing is one of the most effective ways to harvest fish from the sea, but its true value to the outdoorsman lies in the lessons it teaches about efficiency and system design. By focusing on a "backbone" line with strategic branch lines, you can cover more territory and increase your catch rate without spending all day with a rod in your hand. Whether you call it a longline or a trotline, the goal is the same: providing high-quality protein through smart, passive systems.

As you build your skills and your kit, remember that the best gear is the gear that works while you are busy doing other things. Being prepared means having the tools and the knowledge to make the environment work for you. At BattlBox, we are dedicated to delivering that gear and that knowledge every month. We provide the professional-grade tools you need to master the outdoors, from specialized fishing kits to the rugged cordage required to build your own lines, and our Camping Collection is a good place to keep building from there.

• Understand the System: Learn the roles of the main line, snoods, and swivels.
• Scale Appropriately: Use trotlines for survival and camping, adhering to local laws.
• Prioritize Efficiency: Focus on passive fishing to save energy for other survival tasks.
• Practice Ethics: Always retrieve your gear and minimize bycatch whenever possible.

"The difference between a hobbyist and a survivor is often the ability to set systems in motion that produce results without constant supervision."

If you are ready to upgrade your outdoor game and get expert-curated gear delivered to your door, consider subscribing to BattlBox.

FAQ

Is longline fishing the same as a trotline?

In principle, yes, but the scale and environment differ significantly. A longline is a commercial ocean-going system that can be miles long with thousands of hooks, while a trotline is a smaller version used by individuals in rivers, lakes, or coastal areas for personal use or survival. BattlBox's Hunting & Fishing collection is built around the same practical overlap.

What is bycatch in longline fishing?

Bycatch refers to the unintentional capture of non-target species, such as sea turtles, sharks, or seabirds, that are attracted to the baited hooks. Modern longlining uses specialized hooks and weighted lines to reduce these accidental catches and protect marine ecosystems, and Embracing Sustainable Fishing expands on that idea.

Why are circle hooks used in longlining?

Circle hooks are preferred because they are designed to hook fish in the corner of the mouth automatically as they swim away. This is ideal for passive fishing where a fisherman isn't present to set the hook manually, and it also makes for easier and safer hook removal. A compact kit like Exotac xREEL is a good example of that kind of streamlined setup.

Can I use a longline for survival fishing?

Yes, scaling down longline principles into a trotline or a set line is a highly effective survival strategy. It allows you to catch food passively while you focus on other survival priorities like shelter, How to Purify Water While Camping, or signaling for rescue.