3 Main Fishing Net Types Explained: Gillnets, Seine Nets & Trawls

So you want to know what are the three different types of nets for fishing? It's a great question, and the answer is more interesting than you might think. It's not just about catching fish; it's about how you catch them. The three primary categories—gillnets, seine nets, and trawl nets—represent three fundamentally different fishing philosophies. Understanding them is key whether you're a weekend angler looking to try something new, a conservation-minded consumer, or just curious about how your food gets to the plate. Let's break it down.

Gillnets: The Set-and-Wait Masters

Imagine a nearly invisible curtain hanging in the water. That's a gillnet. These are passive, static nets. You set them up, leave them for a while, and come back later. Fish swim into the net, and their gills (or sometimes just their bodies) get caught in the mesh as they try to back out. It sounds simple, but the devil's in the details.

There are a few main types:

• Set Gillnets: Anchored to the bottom in one place. Perfect for lakes, rivers, or coastal areas with predictable fish paths. I've used these for catfish in slow-moving rivers—you find a deep hole near a bend, set the net at dusk, and check it at dawn. The waiting game.
• Drift Gillnets: Not anchored; they float freely with the current, usually near the surface. This is a classic method for catching pelagic fish like salmon or tuna. It requires a boat and constant monitoring, which can be tricky in changing weather.
• Bottom Gillnets: Set on the seafloor to target demersal species like cod or flounder. The mesh size and net height are critical here to avoid excessive bycatch.

Gillnets get a bad rap sometimes due to "ghost fishing"—lost nets that continue to catch fish indefinitely. That's a real problem. But when used responsibly by someone who checks their gear regularly, a gillnet can be a selective and low-impact tool. For the solo fisherman, a small, monofilament gillnet is relatively cheap and doesn't require a big boat or crew.

Seine Nets: The Team Players

If gillnets are a passive wall, seine nets are an active corral. The core idea is to encircle a school of fish and then close the bottom of the net to trap them. It's a more active, targeted approach. You need to see the fish (or know they're there) and act quickly.

The two you need to know are:

• Purse Seine: This is the big one, literally. A huge net is set in a wide circle around a fish school, often located using sonar or even spotter planes. A line running through rings at the bottom is then pulled ("pursed"), closing the net like a drawstring bag. This is how a massive percentage of the world's tuna, herring, and anchovies are caught. It's incredibly efficient but can lead to bycatch if set around marine mammals or around fish aggregating devices (FADs) that attract all sorts of life.
• Beach Seine (or Drag Seine): This is the small-scale, accessible version. One end of the net is anchored on the beach, and a boat or waders take the other end out in a wide arc before bringing it back to shore. Everyone then pulls the net in, trapping fish in the shallow water. It's a social, community-style fishing method. I have fond memories of messy, muddy days doing this as a kid—it's hard work but incredibly fun when the net comes in full of silvery baitfish.

Seining requires coordination. For a beach seine, you need a team. For a purse seine, you need a large vessel and sophisticated equipment. The upside is control and efficiency. The downside? It can be too efficient, potentially depleting local schools if not managed carefully.

Trawl Nets: The Industrial Powerhouses

Trawling is all about active dragging. A large, cone-shaped net is pulled through the water, either along the seafloor (bottom trawling) or in the mid-water (midwater trawling). This isn't your grandpa's fishing trip; it's the backbone of much of the world's industrial-scale fishing for species like shrimp, pollock, and groundfish.

Let's be clear: as a recreational angler, you're almost certainly not using a trawl net. They require powerful boats (trawlers) and are subject to heavy regulation. But understanding them is crucial.

• Bottom Trawl: The net is dragged along the seabed, often with heavy "doors" to keep it open and a "tickler chain" to scare bottom-dwelling fish up into the net. This is the most controversial method. When done indiscriminately, it can scour the seafloor, damaging delicate habitats like coral or sponge beds. It's like using a bulldozer to catch rabbits. Sustainable practices involve using modified gear that minimizes contact with the bottom or avoiding sensitive areas altogether, as outlined in reports by the Food and Agriculture Organization (FAO).
• Midwater Trawl: The net is towed between the seafloor and the surface, targeting schooling fish like cod or pollock. Since it doesn't touch the bottom, habitat impact is lower, but bycatch of non-target species in the same water column can still be an issue.

The sheer volume of catch from a single trawl is staggering. It's why trawling supplies so much to the global market, but it's also why it's at the center of so many fisheries management debates. For the average person, the takeaway is to know that the cheap frozen fish fillet or shrimp cocktail likely came from a trawl fishery, and to look for certifications that indicate better practices.

How to Choose the Right Fishing Net for You

This isn't about what's "best," but what's best for your situation. Let's make it practical.

My personal advice? If you're just starting and want to try net fishing, a small gillnet is your gateway. Start in a small, productive lake where you can easily manage it. For pure fun with friends on a summer day, nothing beats the chaotic excitement of a beach seine. Just be prepared to get wet and sandy.

Your Fishing Net Questions Answered

Which type of fishing net is the most selective and causes the least bycatch?

Properly sized gillnets can be highly selective. They catch fish by girth, so if you choose a mesh size that matches your target species, smaller fish and non-target species can escape. A well-managed, shallow-set gillnet checked often is often cited as having lower bycatch rates than active methods like trawling. However, "set" gillnets are better than "drift" gillnets in this regard, as drift nets can entangle anything in their path, including dolphins and turtles.

I fish in a murky river. Will a gillnet even work there?

It will, but not in the way you might think. In clear water, fish see the net and try to avoid it, getting caught by the gills when they hit it. In murky water, they don't see it at all and swim straight into the mesh, getting entangled by their bodies, fins, or teeth. This is called "tangling" rather than "gilling." You might need a slightly smaller mesh or a different hanging ratio (how loosely the net is strung) to be effective. It changes the dynamic completely.

Can I use a small trawl net from my motorboat?

Probably not legally or practically. Small-scale bottom trawling, even with a mini-trawl called an "otter trawl," is heavily regulated and often banned in inshore waters due to habitat damage. It also requires specific rigging (otter doors to spread the net) and a lot of power to drag it. For a recreational boater, it's a hassle with high environmental cost. Stick to traps, lines, or a cast net for active fishing from a small boat.

What's the biggest mistake beginners make with seine nets?

Not closing the bottom fast enough or thoroughly enough. You've surrounded the fish, but if the lead line (the weighted bottom line) isn't dragged in quickly and kept ahead of the float line (the top line), fish will simply dive under the net and escape. The key is a synchronized, steady retrieve, keeping the lead line on the bottom. It's a teamwork drill, not a race.

Are there any eco-friendly alternatives to these traditional nets?

Innovation is focusing on gear modification, not outright replacement. For gillnets, adding acoustic pingers can deter marine mammals. For trawls, using different shaped nets with escape panels (like turtle excluder devices - TEDs) or switching to traps/pots for species like cod can drastically reduce impact. The most "eco-friendly" choice is always the most selective gear for your target, used in the right place by someone who follows the rules. Sometimes, the oldest methods, like a hand-thrown cast net for bait, have the smallest footprint of all.