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What is a Blackfish?

Bethney Foster
Bethney Foster

Blackfish is a term used to describe several types of fish and two types of cetaceans. Fish commonly referred to by the term include the Alaska blackfish, the Sacramento blackfish, and the river blackfish. The melon-headed whale and the killer whale, also known as an orca, are also referred to by this name.

The Alaska blackfish, Dallia pectoralis, is a cylindrical fish that is olive brown in coloring. The fish has four to six dark spots that run vertically down its side, and it has a white belly. The fins have red-brown speckles. Reaching lengths of 7 inches (17.7 cm), the fish are found in Alaska and the islands of the Bering Sea.

Squid comprises the primary diet of blackfish.
Squid comprises the primary diet of blackfish.

The Sacramento blackfish, Orthodon microlepidotus, is found in central California. This fish is the only member of the genus Orthodon. Dark in color over its entire body, the fish is lighter as a juvenile and grows darker as it matures. Growing to lengths of 21.5 inches (55 cm), the fish is common in the Sacramento and San Joaquin Rivers. They are also found in the waters that run into the San Francisco Bay.

"Blackfish" can refer to the Alaska blackfish.
"Blackfish" can refer to the Alaska blackfish.

The River blackfish, Gadopsis marmoratus, is found in the fresh water of Australia’s Murray-Darling river system from Queensland to Victoria. A nocturnal carnivore, the fish’s diet consists of crayfish, shrimp, and other small fish. Reaching lengths of 11.8 inches (30 cm), the fish are in decline because of overfishing, competition from introduced species, and siltation of streams.

The orca may be referred to as a "blackfish."
The orca may be referred to as a "blackfish."

The melon-headed whale, Peponocephala electra, is sometimes referred to as the many-toothed blackfish or the electra dolphin. This whale is part of the dolphin, or Delphinidae, family. The entire family is often called by the common name blackfish. The killer whale, Orcinus orca, is also part of this family.

The melon-headed whale is found in most of the world’s tropical waters. The body of the whale is light gray, and the face, which is a rounded cone-shape, is dark gray. Reaching lengths of 10 feet (3 m), the primary diet of the melon-headed whale is squid.

The killer whale is the only species in the genus Orcinus. With a black back, white sides, and a white chest, the killer whale has a white patch above and behind the eye. Calves have a yellowish tint that fades to white. Male killer whales average 20 to 26 feet (6 to 8 m) in length, and females are 16 to 23 feet (5 to 7 m).

Frequently Asked Questions

What exactly is a blackfish?

A blackfish is not a specific species but a colloquial term that generally refers to several species of dark-colored cetaceans, such as killer whales (Orcinus orca), pilot whales, and melon-headed whales. These marine mammals are known for their intelligence and complex social structures, often living in pods with intricate communication systems.

Are blackfish and killer whales the same?

Yes, killer whales, also known as orcas, are a type of blackfish. They are the largest members of the dolphin family and are recognized by their distinctive black and white coloring. Orcas are apex predators, meaning they are at the top of the food chain and have no natural predators.

How do blackfish communicate with each other?

Blackfish communicate using a variety of sounds, including clicks, whistles, and pulsed calls. Each pod tends to have its own dialect, which is thought to be learned behavior. This sophisticated communication is crucial for social interaction, hunting, and navigation in the ocean's depths.

What is the social structure of blackfish like?

Blackfish exhibit complex social structures, often living in matrilineal groups, where leadership and knowledge are passed down from mother to offspring. These family units can form larger pods, which cooperate in activities like hunting. Social bonds are strong, and individuals may stay with their birth pod for life.

What do blackfish eat?

The diet of blackfish varies by species. Killer whales, for instance, have diverse diets that can include fish, seals, and even large whales. Their hunting strategies are sophisticated and can involve teamwork, such as creating waves to wash seals off ice floes. Diet specifics depend on their habitat and available prey.

Are blackfish endangered?

The conservation status of blackfish species varies. According to the International Union for Conservation of Nature (IUCN), some populations of killer whales are considered endangered due to threats like pollution, reduced prey availability, and habitat disturbance. Conservation efforts are crucial to protect these intelligent marine mammals for future generations.

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    • Squid comprises the primary diet of blackfish.
      Squid comprises the primary diet of blackfish.
    • "Blackfish" can refer to the Alaska blackfish.
      By: Joy Prescott
      "Blackfish" can refer to the Alaska blackfish.
    • The orca may be referred to as a "blackfish."
      By: desertsolitaire
      The orca may be referred to as a "blackfish."