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Coastal Cutthroat Trout

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Oncorhynchus clarkii clarkii

Also known as: Sea-run Cutthroat Trout, Harvest Trout, Blueback

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Description

The Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) is a subspecies of cutthroat trout native to the Pacific coast of North America. It is highly adaptable, exhibiting both resident (freshwater) and anadromous (sea-run) life histories. Known for its distinctive red or orange slashes under the jaw, it is a prized sport fish and an important component of its native ecosystems.

Physical Characteristics

Body shape
torpedo
Coloration
Highly variable depending on habitat and life history. Freshwater residents are typically olive-green to brassy-yellow on the back, fading to silvery sides and a white belly. Sea-run individuals are bright silver with a dark back, often with a bluish sheen. All forms have numerous small, irregular black spots concentrated towards the tail. The most distinctive feature is the red to orange 'cutthroat' slash on the underside of the lower jaw, though this can be faint or absent in some individuals, especially sea-run fish.
Scale type
cycloid
Mouth position
terminal
Distinctive features
Red or orange 'cutthroat' slashes on the underside of the lower jaw (can be faint or absent)., Numerous small, irregular black spots, often concentrated on the posterior half of the body and fins., Maxillary bone extends well beyond the posterior margin of the eye in adults., Presence of basibranchial (hyoid) teeth, which can be felt by running a finger along the floor of the mouth.
Dorsal fin
Single, relatively short dorsal fin, typically with 10-12 rays.
Tail fin
Slightly forked to truncate caudal fin.
Pectoral fin
Paired pectoral fins, moderately sized.
Distinctive fins
Adipose fin present, characteristic of salmonids. Pelvic fins are abdominal.

Identification Tips

Cutthroat Slashes

Look for the distinctive red, orange, or yellow-orange markings on the underside of the lower jaw. These can vary in intensity and may be faint or absent in some individuals, especially sea-run fish.

Spotting Pattern

Coastal Cutthroat Trout typically have numerous small, irregular black spots, often more concentrated towards the tail and on the dorsal and caudal fins. This differs from Rainbow Trout (Oncorhynchus mykiss) which tend to have more evenly distributed spots.

Maxillary Length

In adults, the maxillary bone (upper jaw bone) extends noticeably beyond the posterior margin of the eye. This is a key differentiator from Rainbow Trout, where the maxillary typically does not extend as far.

Basibranchial Teeth

A definitive identification feature is the presence of basibranchial (hyoid) teeth on the floor of the mouth. These can be felt by gently running a finger along the tongue area. This feature is absent in Rainbow Trout.

Coloration

While variable, freshwater forms often have a more olive to brassy hue, while sea-run forms are distinctly silvery with a darker back.

Habitat

Water type
freshwater
Depth
Typically found in shallow to moderate depths of streams, rivers, and coastal estuaries. Sea-run forms inhabit nearshore marine environments.
Environment
Cold, clear, well-oxygenated streams, rivers, lakes, estuaries, and nearshore marine waters. Prefers areas with complex cover such as undercut banks, large woody debris, and riparian vegetation. Spawning occurs in gravel-bottomed streams.
Geographic range
Pacific coast of North America, from Prince William Sound, Alaska, south to the Eel River in northern California. Extends inland to the Cascade Mountains.

Aquarium Information

  • Care level: expert
  • Temperament: territorial
  • Diet: carnivore
  • Minimum tank size: Not suitable for typical home aquaria due to size, specialized needs, and legal restrictions. Requires very large, specialized cold-water systems.
  • Temperature: 10-18°C (50-65°F)
  • pH level: 6.5-8.0
  • Hardness: Soft to moderately hard (50-200 ppm)
  • Compatibility: Generally solitary or with conspecifics in very large, naturalistic setups. Not compatible with most other aquarium fish due to predatory nature and specific environmental requirements.
  • Special requirements: Requires highly oxygenated, cold, clean water with strong filtration and flow. Anadromous forms require access to both freshwater and saltwater environments, which is impractical in captivity. Legal permits are often required for possession.

Wild Information

  • Conservation status: least concern
  • Seasonality: Resident populations are available year-round in freshwater. Anadromous populations typically enter freshwater streams from late summer through fall for spawning, and smolts migrate to sea in spring.
  • Market price: Not typically a commercially harvested species; primarily a sport fish.
  • Commercial importance: low
  • Taste: Mild, delicate, often described as less oily than salmon.
  • Texture: Flaky, tender.
  • Cooking methods: Baking, Grilling, Pan-frying, Smoking
  • Nutritional value: Good source of protein, Omega-3 fatty acids, and Vitamin D.

Key Facts

Anadromous and Resident Formsbehavior

Coastal Cutthroat Trout exhibit both resident (freshwater-only) and anadromous (sea-run) life histories within the same populations, showcasing remarkable adaptability.

Estuary Dependencebehavior

Sea-run Coastal Cutthroat Trout spend a significant portion of their marine life in estuaries and nearshore coastal waters, making these habitats crucial for their survival.

Opportunistic Predatorsbehavior

They are highly opportunistic feeders, consuming a wide variety of aquatic and terrestrial insects, crustaceans, and smaller fish, adapting their diet to seasonal availability.

Short Marine Migrationsbehavior

Unlike many other salmonids, sea-run Coastal Cutthroat Trout typically undertake relatively short marine migrations, often staying within 10-20 miles of their natal stream.

Indicator Speciesinteresting

Due to their sensitivity to habitat degradation and water quality, Coastal Cutthroat Trout are often considered an indicator species for the health of Pacific Northwest aquatic ecosystems.

Safety Information

Safe
  • Safety level: safe
  • Venomous: No
  • Edibility: edible
  • Handling notes: Handle with care, especially when practicing catch-and-release. Minimize air exposure, use wet hands or a knotless net, and support the fish horizontally. Avoid squeezing or touching the gills. Their small, sharp teeth can cause minor scrapes, but they are not dangerous.

Similar Species

Rainbow Trout

Oncorhynchus mykiss

Rainbow Trout typically lack the red/orange cutthroat slashes (though some hatchery strains may show faint markings), have fewer and more evenly distributed spots, and their maxillary bone usually does not extend past the eye. They also lack basibranchial teeth.

Coastal Rainbow Trout (Steelhead)

Oncorhynchus mykiss irideus

Steelhead are the anadromous form of Rainbow Trout. They are very silvery like sea-run cutthroat but lack the cutthroat slashes and basibranchial teeth. Their spotting pattern is also generally different, with fewer spots on the tail.

Other Cutthroat Trout Subspecies

Oncorhynchus clarkii spp.

Distinguishing Coastal Cutthroat from other inland cutthroat subspecies (e.g., Westslope, Yellowstone) often requires genetic analysis or detailed meristic counts, as their geographic ranges are generally distinct and morphological differences can be subtle. Coastal Cutthroat are typically more heavily spotted than many inland subspecies.

Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Salmoniformes
Family
Salmonidae
Genus
Oncorhynchus
Species
Oncorhynchus clarkii

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