What is the intertidal zone?

It's nothing at all when the tide is high

It's just a bunch of waves

They whip all around the rocks

And chase all the fish into caves

But if you get there when the tide is low

And the pool is clear and clean

You can see to the bottom

The damnedest collection of creeps

you ever seen

Hungry flowers that feed on fish

Scooping in whatever comes

Crabs that grab another crab

And chew his legs, the dirty bum!

Starfish having himself a lunch

Eats a mussel off a shell

Shrimps and limpets and snails and eels

What a smelly tale they tell

Biting each other and eating each other

and lousing up the sea

Stupid sons of fishes, if you're asking me!

by Richard Rogers and

Oscar Hammerstein III, Pipe Dream

At the border between land and ocean there exists a wondrous diversity of life that can only

be viewed by land lubbers at certain times of the day, and at other times surrenders itself to

the fish and the crabs. This favourite location of beach combers is, of course, the intertidal zone!

Strongylocentrotus droebachiensis

Common Name : green sea urchin

Kingdom: Animalia

Phylum: Echinodermata

Class: Echinoidea

Order: Echinoida

Family: Stronglyocentrotidae

Genus: Strongylocentrotus

Species: S. droebachiensis

Quick facts:

>green urchins are admired for their exceptional sweetness. Digging into a

sea urchin is like eating a delicious fruit or flower from the sea.

>This mostly light green sea urchin is found in the low tide and subtidal zones in temperate and arctic waters on both sides of the Atlantic coast and from Alaska to Puget Sound on the Pacific coast. This species is the most abundant species on the New England coast.

Ophiothrix spiculataCommon name: Brittle star

spiny brittle star (Ophiothrix spiculata)

>The spiny brittle star shelters in crevices or under rocks in the intertidal zone. Its range extends along the Pacific coast from central California to Peru and offshore to the Galápagos Islands.

Domain EukaryaKingdom AnimaliaPhylum EchinodermataClass OphiuroideaOrder OphiuridaFamily OphiodermatidaeGenus OphiothrixSpecies spiculata

COMMON NAME: brittle star

>The spiny brittle star is named for the distinct thornlike spines on its disc and arms. To feed, the brittle star uses the spines of at least one arm to anchor into a crevice and then extends its other arms into the water to entrap food particles on a sticky substance emitted by the spines and tube feet. The tube feet along each arm then coordinate to transfer food particles to the brittle star's mouth.

Pagurus armatus

Common name: hermit crab

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Crustacea

Class: Malacostraca

Oder: Decapoda

Family: Paguroidea

Genus: Pagurus

Species: Armatus

Cool Facts> Hermit crabs prefer certain shells. Pagurus samuelis, a common tide pool hermit crab, prefers the shells of black turban snails.Hermit crabs move into larger shells as they grow—fighting with other hermit crabs for the shells if necessary—but they don’t harm healthy snails.

> This widespread hermit crab genus is a common occupant of intertidal zones throughout the world. Hermit crabs are named for their unusual behavior of inhabiting empty gastropod shells to protect their soft abdomens. They have a soft anterior part of the carapace and an abdomen that is adapted and curved to fit within a shell. The shell is held on through contraction of the abdominal muscles and gripped with modified uropods (the sixth pair of abdominal appendages) and the last two pairs of thoracic legs. The chelipeds block the shell opening when the hermit crab withdraws into the shell for extra protection or can be used to pick up food particles. As the hermit crab grows, it must find a larger shell to move into. Although, hermit crabs often steal shells from each other, they do not take shells occupied by live snails.

Mytilus californianus (California Mussel)Description: Blue/black in colour, often with a streak of brown. Ridged surface.Range: Alaska to Mexico

Habitat: Exposed rocky intertidal.Cool Fact: Females can produce 100 000 eggs/year! Attached to rocks with tough strands called "byssus threads".

Kingdom: Animalia Phylum: Mollusca Class: Bivalvia Subclass: Pteriomorpha Order: Filibranchia Suborder: Mytilacea Family: Mytilidae Genus: Mytilus Species: M. californianus

Littorina sitkana (Sitka Periwinkle)Description:  Black, brown, or white shell. Rounder than L. scutulata and with definite raised ridges.Range: Alaska to Puget Sound, Washington.Habitat: On seaweed and rocks, throughout the entire intertidal.Cool Fact: Can survive out of the water for long periods and will actually drown if submerged for too long!

Kingdom: Animalia Phylum: Mollusca Class: Gastropoda (unranked): clade Caenogastropodaclade Hypsogastropoda

clade Littorinimorpha Superfamily: Littorinoidea Family: Littorinidae Genus: Littorina Species: L. sitkana