Author: Rose Desi-Seulean
Arctic Cookie Star
Common Names: Arctic Cookie Star
Scientific Name: Ceramaster arcticus
Size Range: 11cm (4.2in) across
Identifying Features: The Arctic Cookie Star is typically pink with darker red accents in color. The arms and disc is bordered by large marginal plates. The Arctic Cookie Star is pentagonal, rigid and its arboreal (top) surface is usually covered with small flat-topped plates.
Habitat: Most Arctic Cookie Stars tend to live close to shore, typically interdial to 186m (620 ft.). They can be found around the Aleutian Islands (Attu) and anywhere from Alaska to the Strait of Juan de Fuca, south of British Columbia and into Washington State.
Food: Arctic Cookie Stars prey upon various species of sponges including the Peachball Sponge (Suberites montiniger). They also eat shellfish, mussels and mollusks.
Predators: Sunfish, sea turtles, manta rays, sharks and larger starfish are a big threat to the Arctic Cookie Star. Humans also are a big threat to most sea life whether it’s a souvenir they steal from the beach, an oil spill or just simply littering, we are definitely harming the Arctic Cookie Star.
Life Cycle: Like most sea stars, the Arctic Cookie Star reproduces through external fertilization. Sperm is first produced in the testes of the males and eggs are produced in the ovaries of the females; Cookie Stars are not hermaphrodites. Both gametes are shed in open water, where fertilization takes place. The larvae, which have bilateral symmetry, swim around for sometime and then swim to the ocean bottom where they develop into adults that have radial symmetry.
Author: Yunfei Gong Common name: Vermillion star Scientific name: Mediaster aequalis Size range: 5 inches
Author: Yunfei Gong
Common name: Vermillion star
Scientific name: Mediaster aequalis
Size range: 5 inches
Mediaster aequalis is one of the smallest sea stars ranging in size from three to seven inches. It is a red, 5 armed (rarely,4 to 6 armed specimens) star with a distinctive round texture on its surface. This sea star is named because of its bright color. It is vermillion aborally and more orange on the oral side.
Mediaster aequalis is found along the west coast of North America, ranging from Alaska to California. It is found on many types of beaches at very low tides, particularly on negative tide. The Vermillion Sea Star is common in shallow subtidal waters down to about 160m depth. It is often found on rocks shell, sand, gravel, pebbles and mud.
The Vermillion Sea Star eats a variety of living prey such as sponges, brachiopods, worms, bryozoans, tunicates and the Ptilosarcus gurneyi. It also scavenges dead animals and consumes detritus. Similar to other sea stars, they flip their stomachs out through their mouth and onto the prey they are eating. After selecting enzymes onto its prey and digesting it externally, it pulls its stomach back into its body again.
Sea stars do not have many predators because their outer skin is quite tough. But they do have some predators such as sharks, sea otters and other large fish and sea birds. They can curve their arms and turn into a ball to protect themselves. They also have the ability to regrow their arms if they are eaten by predators.
Sea stars can reproduce in both sexual and asexual ways. Vermillion Sea Stars reach sexual maturity within four years. As sea stars the males and females are in separate individuals. The eggs which are 1 to1.2mm are bright opaqe orange.
Photos by Yunfei Gong
The Stiff-Footed Sea Cucumber is white to cream coloured with eight large, yellow tentacles and two smaller ones which are used to collect food. This sea cucumber has tube-like feet covering its whole body. The size of the cucumber can vary from 4 cm to 10 cm long and its body wall is poisonous to certain types of fish.
This creature can be found under and between rocks along the coasts from Alaska to California. They are often found living in shallow rocky areas and underneath docks. They are also commonly found along the underside and edges of floating docks.
With its mucous covered tentacles, the Stiff-Footed Sea Cucumber is a filter feeder that collects small particles such as plankton and small decaying organic matter for food. It generally does this by holding its tentacles in the current and filtering out food items that stick to the “tree” of tentacles. It then takes each tentacle (which is a modified tube foot) places it into its mouth and takes the food off of it. It then withdraws the tentacle and places it back in the current.
The main predator of these sea cucumbers is the sea star Solaster stimpsoni.
Sea cucumbers are either male or female and they reproduce by releasing sperm and eggs into the ocean water. Spawning occurs in the spring and the egg, embryos and larvae are greenish in colour. The egg is inserted into a pouch on the adult’s body where it develops and eventually hatches from the pouch as a baby sea cucumber.
Sand Dollar Author: Molly Simpson and Emma Troost Common Name: Sand Dollar Scientific Name: Dendraster excentricus Size Range: Up to 10cm in diameter
Author: Molly Simpson and Emma Troost
Common Name: Sand Dollar
Scientific Name: Dendraster excentricus
Size Range: Up to 10cm in diameter
Sand dollars have no front, back, head or tail; instead they have a bottom (oral side) and a top (aboral side). They are round disc-shaped creatures that have a diameter generally about 10cm when fully grown. When living, sand dollars are dark purple/black in colour but after death they turn a creamy white. On their aboral side there is a symmetrical design that resembles a flower with five petals. The shell, called a test, is penetrated by small brown spines that give it a velvety look and enable movement.
Sand dollars live in the Pacific, Atlantic, and Arctic oceans. They live in the sand in the intertidal zone, around 90m deep. They live in groups, called beds, of varying sizes with as many as 625 in one square yard of sand. They prefer sheltered bays, sandy lagoons, or otherwise the shallow water of the open ocean. Generally you will find sand dollars along the North American east coast, or in British Columbia, Siberia or Japan.
Sand dollars eat algae, fragments of organic material, crustacean larvae, diatoms, copepods, and detritus. In calm waters, sand dollars use a method called suspension feeding to eat. In suspension feeding, they position themselves so that one edge of their test is buried in the sand and one is sticking up so that the hole on their oral side (their mouth) is right above the sand and they can catch food sitting or moving on the bottom. Sand dollars have 5 teeth set up in a symmetrical pattern in a structure called an Aristotle’s lantern. It can take them 15 minutes to chew their food and up to 2 days to digest it. They have spines which enable movement. The spines have fine hair like cilia on them that are coated with mucus and bring smaller food to the mouth. They also have tube feet, which are small suction cup like tentacles about as small as their spines. They use these tube feet to help them move around and bring larger food to their mouth.
Sand dollars, being slow, have many predators, including snails. Their main predators are: the large pink sea star, the Starry Flounder, the California Sheep Head, sea gulls, crabs, otters, and octopuses. To protect themselves they dig into the sand where they won’t be found by any of their predators.
Sand dollars live anywhere from 8-13 years; you can tell how old they are by the growth rings on their test. When spring begins the mating cycles begins too. Once the salinity and temperature of the water is just right the females release their eggs and the males release their sperm. Once sperm and egg meet they immediately develop into larvae via cell division. After a month of floating the larvae settle into the sand and start growing a test to become adults.
How to find and preserve a sand dollar test: The best time to find sand dollars is after a large storm when they wash ashore and die, leaving a white shell, called a test, behind. To prevent them from stinking put them in a diluted bleach solution and let them sit for about 15 minutes. Afterwards rinse them off, let them dry, and you have a beautiful white sand dollar test! Live ones should of course be left in the ocean.
Habitat: Red Sea Urchins can be found on both rocky shorelines where there is a lot of wave action and on quite shores. They live in the low intertidal zone to 91 meters deep. In the Pacific Northwest you would more likely find the Green and Purple Sea Urchins in the low intertidal area than the larger Red Sea Urchin; they are generally found in deeper water.
Food: All sea urchins eat seaweed. The Red Sea Urchins prefer to eat kelp (brown seaweed) and red seaweed, however in our aquarium they have been observed eating a diversity of things including Eel Grass (Zostera marina). On one occasion a Bay Pipefish (Syngnathus leptorhynchus) was captured by the tube feet of our Red Sea Urchin and eventually eaten. Sea Urchins use their tube feet to pass the food that they find into their jaws, where their 5 teeth (aristotles lantern) chew the food as they take it into their mouth and digestive tract.
Predators: The hard test and spines give the Red Sea Urchin some protection from its predators but they aren’t venomous. The main predators of this species include sea stars, sea otters, octopus, crabs, and wolf eels. In Japan, people eat the Red Sea Urchin’s reproductive organs as a delicacy.
Life Cycle: Red Sea Urchins fertilize in water column. After a period the fertilized eggs develop into larvae. It takes 6 to 8 weeks for the larvae to develop into juvenile sea urchins. Adult urchins can live up to be 7 to 10 years old.
Authors: Emma Grigg & Nastja Kharine
Common Name: Purple Sea Urchin.
Scientific Name: Strongylocentrotus purpuratus
Size range: up to 15 cm (6 inches) across.
Identifying Features: As in its name, the Purple Sea Urchin is purple but it can also be a purplish green colour. The Purple Sea Urchin is a medium sized sea urchin compared to its relatives the Green and Red Sea Urchin, measuring up to 15 centimeters across. It has a circular body covered in heavy spines. These spines cover the entire crust-like body acting as protective armor.
Habitat: Purple Sea Urchins are found from the coast of Alaska to the north of Mexico. They live in water up to about 160cm (63inches) deep on rocky coastlines. They use their spines to dig holes in pebbles, sand and rock to create a protective groove. These grooves are their homes and they shelter the urchins from crashing waves. Purple sea urchins like living with their friends and family, so you can usually find them in groups.
Food: The Purple Sea Urchin eats mostly algae. It has teeth that help it pull algae off rocks. They are also known to eat plankton, kelp, periwinkles, barnacles, mussels, dead fish and sea sponges.
Predators: Many things eat Purple Sea Urchins, even though they have huge spines. Crabs, sunflower stars, snails, sea otters, some birds, fish and people like Purple Sea Urchins on their menus.
Life Cycle: Purple Sea Urchins usually live up to 30 years or longer. They breed around January to March every year. The female sea urchins can produce up to twenty million eggs in one year. When the female sea urchins lay their eggs, the young urchins start off as larvae. It takes a few months for the larvae to develop into small baby sea urchins. It takes 2-5 years before a new sea urchin can reproduce.
Life Cycle Sea stars can reproduce sexually and asexually. They reproduce asexually by dividing their bodies and regenerating missing parts. The decapitated starfish limb can grow into a new sea star, so long as a part of the central body portion is attached. In sexual reproduction, a sea star’s eggs are externally fertilized by a male sea star’s spermatozoa. The fertilized eggs develop into swimming larvae categorized into two groups: Bipinnaria and Brachiolaria. These larvae use cilia to move and eventually settle to the ground when growing into adults. When developing into a fully grown sea star, the larva’s left side will become its oral structures, facing the ground, and its right side will become it’s back.
Interesting resources for research and photographer credit
Victoria High School
1260 Grant St.
Victoria. BC, Canada