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Fish Measurement


Most finfish size limit regulations use either Fork Length or Total Length.

These measurement methods provide a consistent, well-defined measurement technique and encourage angler compliance with fishery management regulations.

When using a flexible measuring tape, please remember to take a straight line measurement and do not follow the contour of the fish as this will result in an inaccurate measurement greater than the straight line measurement. For best results, place flexible measuring tapes flat on a hard surface and measure fish accordingly.


Red drum measurements

Total Length is measured from the most forward point of the head, with the mouth closed, to the farthest tip of the tail with the tail compressed or squeezed, while the fish is lying on its side.

Mutton snapper measurements

Total length species include but are not limited to:

  • snappers
  • groupers
  • red drum
  • black drum
  • snook
  • spotted seatrout
  • weakfish
  • tripletail
  • bonefish
  • sheepshead
  • flounder
  • several marine life species (angelfish, etc.)
Yellowmouth grouper measurements

How do I measure fish that have ragged-edge type tail filaments, such as scamp, yellowmouth grouper, or black sea bass?

For fish that have "ragged-edge" type filaments, these "pieces" of the tail should be included in the measurement of total length and measured to the "farthest tip of the tail" in the definition for total length.

Spanish Mackerel measurements

Fish regulated by fork length are measured from the tip of the jaw or tip of the snout with closed mouth to the center of the fork in the tail.

Hogfish measurements

Fork length species include but are not limited to:

  • amberjacks
  • rudderfish
  • hogfish
  • dolphin
  • cobia
  • mullet
  • bluefish
  • king mackerel
  • Spanish mackerel
  • permit
  • pompano
  • African pompano
Gray Triggerfish measurements
Billfish measurements

Fish regulated by lower jaw fork length are measured in a straight line from the anterior most part of the lower jaw (tip of the lower jaw) to the fork in the tail.

Lower jaw fork length species include but are not limited to:

  • sailfish
  • white marlin
  • blue marlin
stone crab claw measurement 2 7/8 inches

Stone crab claws must measure at least 2 7/8-inches in length measured by a straight line from the elbow to the tip of the lower immovable finger. The forearm (propodus) is the largest section of the claw assembly that has both a moveable and immovable finger and is located farthest from the body of the crab.

Carapace must be larger than 3

Spiny lobster must have a minimum carapace length of greater than 3-inches and the measurement must take place in the water. The carapace is measured beginning at the forward edge between the rostral horns, excluding any soft tissue, and proceeding along the middle to the rear edge of the carapace.

History of Finfish Measurement in Florida

The state of Florida has wrestled with how to measure saltwater finfish since 1925. In 1925 the Legislature first enacted length measurements for marine finfish. Many different methods have been used over the years (1925-1973) including: tip of nose to fork of tail, tip of nose to tip of tail, tip of nose to end of tail, and tip of nose to rear center edge of tail. At any one time, one or all of these definitions were used. In the late 1980s, both a total length and a fork length size limit were listed in rule for some species. By the mid 1990s, only one measure was chosen for most species primarily based on the way federal regulations specified how the species should be measured. In 2006, the FWC clarified the definition of total length as having a pinched tail and closed mouth. Prior to that, FWC rules did not consistently state how to obtain total length, leaving this measurement open to interpretation by anglers and law enforcement officers.