Butter Sole


The Butter Sole, also known as Isopsetta isolepis, belongs to the family ⁢of flatfishes, Pleuronectidae.

Conservation Status

According to the International Union for Conservation of Nature (IUCN), the current status of the Butter Sole is “Least Concern” ⁢due to its widespread distribution and assumed large population size.

Conservation efforts

While the Butter Sole’s current status requires no urgent conservation, various ‌efforts are ongoing to maintain healthy populations. These include legislation​ limiting the use of destructive fishing gear⁣ and periodic‌ fisheries assessments.


Statistic Value
Length (Average) 30 cm
Length (Range) 20-50 cm
Weight (Average) 1 kg
Weight (Range) 0.5-3 kg
Average Lifespan 8-10 years


Butter ​Sole species are widely spread in the ⁢northeast Pacific Ocean, from the⁤ Bering Sea and Alaska south to Baja ​California, Mexico.

Migration patterns

Butter Sole populations undertake shallow inshore-offshore​ migrations related to ⁣spawning and feeding.


The ‍Butter Sole prefers sandy or muddy ‌substrata in cold (<20°C) marine​ waters, usually⁢ at depths of 9-549 m.

When and Where to See

Butter Sole ⁣are most commonly observed during summer and early autumn, especially during​ daytime when they are more actively feeding.

Best Fishing Locations and Tips

  • Columbia ‌River, USA
  • Prince William Sound, Alaska, USA
  • Vancouver Island, Canada
  • Baja California,​ Mexico
  • Monterey Bay, USA

General tip: Butter sole⁢ are‌ often found near sand‍ or mud bottoms at ⁤moderate depths, so bottom fishing⁣ techniques can be most effective.

How to Catch

Butter⁤ Sole ⁤are often caught ⁣with baited hooks or small lures. Fishing is most effective during the daytime and⁤ in summer to early autumn when the fish are most active.

Identification Guide

Butter Sole has a uniformly dark upper side and pale lower side, ⁤with ‌body depths 2.5-3.0 ⁣times in head length. It can⁤ be easily ‍distinguished from similar species by its small mouth‌ reaching only⁤ to below front of eye and 72-97 dorsal fin rays.


Butter Sole ‌has a sweet, delicate ⁤flavor and ​is often pan-fried, baked, or used in fish soups. It is⁣ nutritionally rich, being a ‍good‌ source of protein, vitamin D,‌ and omega-3 fatty acids.

Additional‌ Information

Butter Sole feeds primarily on polychaetes, ⁣crustaceans, and​ small fishes. Its primary predators​ are larger fishes and marine mammals.

References and Further Reading

Integrated Taxonomic ‌Information System (ITIS)
International Union for‌ Conservation of ⁣Nature (IUCN)