How to Identify Atlantic Halibut

To identify Atlantic Halibut (Hippoglossus hippoglossus), look at these key features.

Physical Characteristics

Body shape

flat

Coloration

Dorsal (eyed) side is typically dark brown, olive, or grayish-green, often mottled with lighter spots, providing camouflage against the seabed. The ventral (blind) side is pure white, sometimes with pinkish or yellowish tinges.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Extremely large size, making it the largest flatfish., Diamond-shaped body, broader towards the head and tapering towards the tail., Small, smooth scales embedded in the skin., Large mouth extending to below the middle of the lower eye, armed with sharp, conical teeth., Strong, crescent-shaped caudal fin (tail).

Dorsal fin

Long, continuous dorsal fin extending from above the eye almost to the caudal fin, with 98-108 rays.

Tail fin

Large, deeply forked (crescent-shaped) caudal fin, powerful for propulsion.

Pectoral fin

Relatively small pectoral fins, positioned on both sides, with the one on the eyed side being slightly larger.

Distinctive fins

Anal fin is also long and continuous, mirroring the dorsal fin, with 73-82 rays. Pelvic fins are small and located anterior to the pectoral fins.

Identification Tips

1. 1

   Size

   Its immense size (up to 4.7 meters or 15 feet in length and over 300 kg or 660 lbs) is a primary distinguishing feature from other flatfish.

2. 2

   Body Shape

   The diamond-shaped body, with a relatively narrow tail stock, is characteristic.

3. 3

   Lateral Line

   The lateral line is distinctly arched above the pectoral fin, then runs straight to the tail. This arch is a key identifier.

4. 4

   Mouth

   A large mouth extending to below the middle of the lower eye, with prominent teeth, indicates its predatory nature.

5. 5

   Coloration

   The dark, mottled eyed side and pure white blind side are consistent.

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