Ron's Critter of the Day

TAXONOMY
Phylum: Chordate
Class: Actinopterygii
Order: Scorpaeniformes
Family: Rhamphocottidae, Grunt Sculpins
Genus/species: Rhamphocottus richardsoni

GENERAL CHARACTERISTICS: Short stocky body. Most of body covered with prickles. Head and body colored yellowish-beige, streaked with dark brown; ventral surface creamy yellow to pale red. Base of caudal fin is bright red. Fin rays mostly reddish.
Their large heads represent over half of their total body length—and feature a long, tapered snout, two bony ridges on top, and small cirri on the upper lip. Instead of scales, their bodies are covered with small plates containing numerous tiny spines.

Length 5-7.6 cm (2-3 in).

DISTRIBUTION/HABITAT: Pacific Ocean, Japan north to Alaska, south to Santa Monica Bay, California. Habitat: Rocky and sandy substrates, tide pools. Grunt sculpins use the barnacles’ shells as protection and egg-laying sites. In this position, the shape of its head resembles the former resident of the shell.

Intertidal to 165 m. (540 ft)

DIET IN THE WILD: Crustaceans. Young consume zooplankton, invertebrate and fish larvae

LONGEVITY: about four years.

REPRODUCTION: Observations in captivity show that during spawning season the female chases the male until he is trapped in a rocky cavern. She keeps him captive until her eggs are laid; fertilization is external. After the eggs are fertilized, the female leaves the male to guard the nest. She may return occasionally to take a shift protecting the eggs. When it’s time for the eggs to hatch, whichever parent is guarding them (male or female) takes the eggs into its mouth, leaves the nest and literally spits the eggs out—breaking the eggs open. The newly hatched larvae then swim away to begin their lives.

REMARKS: Produces grunt-like sounds when removed from water, thus the common name. Eyes operate independently.
Like most sculpins, rarely swims freely in the water column; instead usually “walks” with a hopping motion over the substrate by use of its large, fan-like pectoral fins. Frequently observed taking shelter in empty shells, including those of the giant barnacle, Balanus nubilis, as well as in cans and bottles.

They move by crawling on the tips of their finger-like pectoral fins in a series of twitchy hops, jerks and jumps.

They make a wheezing-grunting sound when removed from the water, hence the name, grunt sculpin.

References

California Academy of Sciences Steinhart Aquarium, Water Planet Locomotion 2018

Ron’s Flickr https://www.flickr.com/photos/cas_docents/15896092713/in/album-72157662278273245/

Ron’s WordPress Shortlink https://fishoncomputer.wordpress.com/wp-admin/post-new.php

Seattle Aquarium https://www.seattleaquarium.org/animals/grunt-sculpin

Aquarium of the Pacific http://www.aquariumofpacific.org/onlinelearningcenter/species/grunt_sculpin/