Deep Fishing Codes: What They Mean & How to Use

Deep fishing codes are compact alphanumeric identifiers used by anglers and charter services to quickly describe a specific fishing trip, location, or technique. You enter the code (or the details it represents) into a calculator and get back a clear, standardized summary of what the code stands for, including target species, depth, and gear type. This page explains how these codes are structured, how to decode them, and how to choose the right one for your next outing.

Formula

The calculator decodes a standard deep fishing code using the pattern: SPECIES-DEPTH-LINETEST. The species part is a 2–4 letter abbreviation (e.g., BFT for bluefin tuna, SWO for swordfish, YFT for yellowfin tuna). The depth is in meters, and the line test is in pounds. The formula extracts these components and displays them separately:

Species = first part of code (letters before the first hyphen)
Depth (m) = number between the first and second hyphens
Line test (lb) = number after the second hyphen

All variables are defined in the code itself. If you enter a code that doesn’t follow this pattern, the calculator will show “Cannot compute� because the structure is invalid.

Worked Example

Using the default code BFT-300-200:

1. Split the code by hyphens: [BFT, 300, 200]
2. Species = BFT (bluefin tuna)
3. Depth = 300 meters
4. Line test = 200 pounds

The calculator outputs: Species = BFT, Depth = 300 m, Line test = 200 lb. This matches the default values exactly.

Background: Why Codes Exist

Deep fishing codes emerged from the need for brevity in radio communications and logbooks. Instead of saying “we’re targeting bluefin tuna at 300 meters with 200-pound line,� a captain can say “BFT-300-200.� This saves time, reduces misunderstanding, and is especially useful in rough seas or when using satellite messengers with limited text. The codes are not standardized by any official body—they are a convention used by many charter fleets and fishing communities. Different regions may use local variations, but the species-depth-line pattern is the most common.

How to Read a Code

To decode a code manually, look for the hyphens. The first segment is the species abbreviation. Common ones include:

• BFT – bluefin tuna
• YFT – yellowfin tuna
• SWO – swordfish
• HAL – halibut
• COD – Atlantic cod

The second segment is always the depth in meters. If you see a number like 300, it means 300 meters (about 984 feet). The third segment is the line test in pounds. A value of 200 means 200-pound test line. Some codes may include additional segments (e.g., BFT-300-200-ELECTRIC) to indicate electric reels or other gear, but the calculator ignores extra parts.

Choosing the Right Code

When you create your own code, consider the following:

• Species: Use the most common abbreviation for the fish you’re targeting. If unsure, stick to the first three letters of the species name (e.g., SWO for swordfish).
• Depth: Use the depth at which you expect to find the fish, not the bottom depth. Many pelagic species stay at specific depths based on temperature and prey.
• Line test: Choose a line strength that matches your target. Heavier line for large fish, lighter for smaller. A general rule is 10 lb of line per 10 kg of fish, but this varies widely.

If you’re using the code for a logbook, include the date separately. The code is meant to describe the trip, not the date.

Common Problems and Misconceptions

One common mistake is confusing depth in meters with depth in feet. Always clarify the unit. Another is using line test in kilograms instead of pounds—this changes the code’s meaning. Some anglers mistakenly put the bottom depth instead of the fishing depth, which can mislead others. Also, species abbreviations are not universal: “HAL� might mean halibut in one region and a different fish in another. Always confirm the code with the person who created it if you’re unsure.

Alternatives to Codes

If you don’t want to use codes, you can simply write out the full description in your logbook or radio call. Some electronic logbook apps allow you to tag entries with species and depth directly. However, codes remain popular because they are concise and work across different systems. For personal use, you can create your own system, but if you share codes with others, stick to the common pattern to avoid confusion.

Safety and Accuracy Notes

When using codes for safety-related communication (e.g., reporting a location), always include your GPS coordinates separately—the code doesn’t contain location data. Also, be aware that line test ratings are not standardized across manufacturers; a 200-lb line from one brand may have a different actual breaking strength than another. For critical applications, verify the actual breaking strength from the spool label. Always follow local fishing regulations regarding depth and gear restrictions.

Frequently Asked Questions

What does BFT-300-200 mean? It means bluefin tuna, fishing at 300 meters depth, with 200-pound test line.

Can I use feet instead of meters in the code? Yes, but you must specify that the depth is in feet, e.g., BFT-984-200. The calculator assumes meters, so if you enter feet, the depth will be wrong.

Are there official code standards? No, these codes are a community convention. Different groups may use different formats, so always confirm the meaning with the person who provided the code.

What if my code has more than three parts? The calculator will ignore extra parts. For example, BFT-300-200-E will still decode as BFT, 300, 200.

How do I choose the right line test? Consider the fish size and the fishing technique. For deep sea trolling, many anglers use 80–200 lb line. For jigging, 50–150 lb is common. Check your reel’s line capacity and drag settings.

Can I use codes for freshwater fishing? Yes, the same pattern works, but the depth will likely be much shallower (e.g., LMB-5-10 for largemouth bass at 5 meters with 10-lb line).

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in code | Code | - | BFT-300-200 | 0
in depth | Depth (m) | m | 300 | 0 | 11000
in line | Line test (lb) | lb | 200 | 1 | 2000
out species | Target species | - | BFT | 0
out depth_m | Depth (m) | m | depth | 0
out line_lb | Line test (lb) | lb | line | 0