The grunt sculpin or grunt-fish (''Rhamphocottus richardsonii'') is a small fish mainly found in the eastern Pacific Ocean. The grunt sculpin generally remains close to shore and is often found in empty

giant barnacle ''Balanus nubilus'', commonly called the giant acorn barnacle, is the world's largest barnacle, reaching a diameter of and a height of up to , and containing the largest known muscle fibres. Classification ''Balanus nubilus'' was named by C ...

shells. The

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

comes from reports that the fish vibrate or "grunt" when held. Its defining feature is its tendency to "hop" along the ocean floor on its orange fins. The short, stout body of the grunt sculpin has a long, small mouth which is adapted for eating smaller prey.

Taxonomy

It is a member of the class

Actinopterygii Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class (biology), class of Osteichthyes, bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built ...

, the ray-finned fishes. It is further classified into the order

Scorpaeniformes The Scorpaeniformes are a diverse Order (biology), order of Actinopterygii, ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of spec ...

, commonly known as the mail-cheeked fishes. The superfamily

Cottoidea A sculpin is a type of fish that belongs to the superfamily Cottoidea in the order Perciformes.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand acros ...

which is classified within this order includes ''R. richardsonii'' and all other sculpins. However, the grunt sculpin was regarded as the only member of the family

Rhamphocottidae Rhamphocottidae is a family of ray-finned fishes belonging to the superfamily Cottoidea, the sculpins. The species in this family occur in the North Pacific Ocean. Taxonomy Rhamphocottidae was first proposed as a family by the American icht ...

until the Ereuniidae was synonymized with Rhamphocottidae. The records from the western North Pacific are now thought to probably refer to '' Rhamphocottus nagaaki'' which was described as a new species in 2022. Its genus name comes from meaning snout and meaning sculpin based on its physical characteristics. Its species name honors the Scottish naturalist John Richardson. It was first formally described by the German born British

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

and

herpetologist Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (in ...

Albert Günther Albert Karl Ludwig Gotthilf Günther , also Albert Charles Lewis Gotthilf Günther (3October 18301February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile tax ...

in 1874 with its type locality given as

Fort Rupert, British Columbia Fort Rupert is the site of a former Hudson's Bay Company (HBC) fort on the east coast near the northern tip of Vancouver Island, British Columbia. The unincorporated community on Beaver Harbour is about by road southeast of Port Hardy, British C ...

Description

The largest recorded length for the grunt sculpin is only 8.9 cm. Its main features are its big head, short, stout body, long pig snout, and orange fins. The body is usually a yellow color with brown stripes contrasted by its very orange

pectoral fins Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

. Compared to other

sculpin A sculpin is a type of fish that belongs to the superfamily Cottoidea in the order Perciformes.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand acros ...

s, it has a small mouth with a longer snout affecting its feeding habits. Although it can swim in an abnormal manner with its head pointing up, it mainly "hops" along the bottom of the ocean using its several pectoral fins. It’s

phenotypically In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties ...

classified by its pectoral fins being separated from the upper lobe, the presence of

anal Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involving ...

and

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

stays, and its hypural-parhypural bone being made of a singular piece.

Distribution and habitat

The grunt sculpin is found around the coasts in the eastern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, stretching from southern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

to the

Bering Sea The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...

, although it has also been seen off of the coast of

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. In these regions, the grunt sculpin resides in a variety of habitats such as

rocky shore A rocky shore is an intertidal area of seacoasts where solid rock predominates. Rocky shores are biologically rich environments, and are a useful "natural laboratory" for studying intertidal ecology and other biological processes. Due to th ...

kelp forest Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on E ...

, sandy beaches, and

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s. In these habitats, it generally remains in shallower waters (as shallow as two meters) but it has been found at depths of 165 meters. It prefers to shelter in empty giant barnacles, but it will also live in debris under piers and floats in the absence of giant barnacles. Within the barnacles, the grunt sculpin will stick out its fins and wave them around to try to mimic the appearance and movement of the cirri of a living barnacle.

Diet

The grunt sculpin has a small mouth for a sculpin, therefore it mainly preys on small

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s but sometimes small fishes and worms as well. Their main predators are rockcod and other

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

fishes. Classifying whether ''R. richardsonii'' are ram or suction feeders is difficult as it has physical features of both types and it feeds on both prey types ( elusive and grasping) with similar success, though it fares better with smaller elusive prey. Ram feeders envelop the prey with a quick movement of their body while suction feeders use negative pressure to draw water and prey into their mouths. Elusive prey are prey that can initiate evasive maneuvers while grasping prey tend to hold onto the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

to avoid being eaten. ''R. richarsonii'' tend to attack with lower velocities and from shorter distances (less than half its body length away) in comparison to other

Cottidae The Cottidae are a family of fish in the superfamily Cottoidea, the sculpins. It is the largest sculpin family, with about 275 species in 70 genera.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology ...

fishes.

Reproduction

Spawning generally occurs at the rocky shores from August to October. The female is the dominant mate in reproduction and will chase and trap the male within a rocky crevice until she has laid all her

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s (about 150). The eggs will hatch 16–20 weeks after

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

depending on the temperature conditions.

Larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e forms have been reported from March to June. The larvae must remain near the shore as that is the habitat in which the grunt sculpin can survive. If the larva is lost to planktonic dispersal in the open ocean then the fish is unlikely to survive. How the larvae are adapted and influenced by environmental factors to remain close to shore is unclear.

References

* * * {{Taxonbar, from=Q302264

grunt sculpin The grunt sculpin or grunt-fish (''Rhamphocottus richardsonii'') is a small fish mainly found in the Pacific Ocean, eastern Pacific Ocean. The grunt sculpin generally remains close to shore and is often found in empty Balanus nubilus, giant barn ...

Fish of the North Pacific Western North American coastal fauna