Archive for January, 2019


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/

TAXONOMY
Phylum: Mollusca
Class: Gastropoda,
Order: Nudibranchia (sea slugs)
Family Tethydidae

Genus/ species: Melibe leonina

YouTube VIDEO  http://youtu.be/Xe2bM2kKm-U

GENERAL CHARACTERISTICS: Color a translucent gray, greenish-gray, or yellowish-gray, with opaque brown hepatic diverticula. Melibe leonina has 4-6 pairs of large, leaflike or paddlelike cerata in two rows down its dorsum and a large oral hood with two rows of filiform tentacles around its margin.

Length up to 102 mm long (4 in), 25 mm (1 in) wide, and 51 mm (2 in) across the expanded oral hood.

DISTRIBUTION/HABITAT: West coast of North America from Alaska to Baja California in eelgrass beds, kelp (especially Macrocystis) beds, harbors. When swimming it is usually upside-down, and undulates back and forth.

DIET:  M. leonina feeds on Copepods, amphipods, and ostracods, as well as small post-larval mollusks. They firmly attache itself to a kelp blade and then sweeps its raised hood downward or to the side. When food lands on the lower surface of the hood, the melibe sweeps together the two sides of the hood, and its fringing tentacles lock in the prey. The hood contracts to force the captured food into the M. leonine’s mouth.

REPRODUCTION and DEVELOPMENT:  M. leonine are hermaphrodites (they have both male and female sexual organs), and fertilization is internal. The animal can lay as many as 30,000 eggs, which are enclosed in a long, gelatinous ribbon.

REMARKS:  Noxious secretions of the melibe smell like watermelon, according to aquarists. They are gregarious animals and probably use it to keep together as well as for defense.  Most predators avoid the noxious secretions of nudibranchs; but the kelp crab is an exception. 

This species has been used for neurological research.

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References

California Academy of Sciences, Steinhart Aquarium, Water is Life 2019

Ron’s WordPress Shortlink wp.me/p1DZ4b-fW

Ron’s flickr www.flickr.com/photos/cas_docents/sets/72157608597736188/

Monterey Bay Aquarium www.montereybayaquarium.org/animal-guide/invertebrates/me…

EOL eol.org/pages/454874/details

 

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