At night, stingrays slowly graze over the sandy seafloor. Since their eyes are on top of their bodies, they depend on electro-receptors and keen senses of smell and touch to find food. To uncover buried prey, stingrays force jet streams of water through their mouths or flop their fins over the sand. If they find a clam, the rays’ stubby teeth are strong enough to easily crush the shells. Then they spit out the fragments.

The rays’ eyes and spiracles are on their brown upper bodies, and their mouths are on their white or yellowish underbellies. The rays have large, flat tooth plates on both jaws that they use to crush hard-shelled prey. The rays spit out crushed shells and eat the soft body parts.

bryozoans,

hydroids

algae

Skeleton shrimp look like, and sometimes are called, "praying mantises of the sea." They have two pairs of legs attached to the front end of their bodies, with three pairs of legs at the back end. The front legs form powerful "claws" for defense, grooming and capturing food. The rear legs have strong claws that grasp and hold on to algae or other surfaces. They use their antennae for filter feeding and swimming.

Juveniles are dark brown with white zebralike stripes, but adults are tan with brown leopardlike spots, so this shark has at least three common names—zebra shark, leopard shark and zebra/leopard shark. Common names can be confusing, which is why we depend on scientific names for identifying animals and plants.

To reproduce, male sharks use claspers (modifications of the pelvic fins) to transfer sperm into the female’s reproductive tract. The zebra female lays fertilized eggs in tough capsules covered with tufts of filaments, which attach the eggs to the seafloor.

To curtail this slaughter of sharks, the United States government passed a law in 2000 that forbids shark finning and possessing shark fins without shark bodies, and prohibits foreign fishing vessels from shark finning in the United States’ exclusive economic zone (EEZ). Canada, Australia, Mexico and New Zealand are also managing shark fisheries, but more countries need to regulate these fisheries.

Ocellated river rays are flat and round with a tail that tapers to a poisonous stinger near the tip of the tail. They aren’t aggressive, but if they’re accidentally stepped on, the rays instantly lash their tails and stab with their poisonous stingers. Stingray wounds are extremely painful and may become infected—so remember to always shuffle your feet when you’re in stingray territory.

Like most rays and skates, ocellated rays have spiracles (holes) behind their eyes, with their mouths and gill slits underneath their bodies. When the rays lie on the river bottom, water enters the spiracles, passes over the gills and exits through the gill slits. The direction of the water flow keeps sand or mud from clogging the gills while supplying the rays with oxygen.

These well-camouflaged sharks stay close to their home base on the seafloor. The more numerous cape sharks prefer deeper and colder water than natal sharks, which live in warmer water close inshore. Like other catsharks, puffadder shysharks have piglike snouts, nasal barbels (fleshy feelers), spiracles behind their eyes and oval catlike eyes.

These "sea slugs" eat hydroids and anemones, which are armed with nematocysts (stinging capsules). These nematocysts don’t harm the nudibranch; in fact, the animal transfers some of its prey’s unfired nematocysts to the tips of its own cerrata, where they become part of the nudibranch's defense system. Some experts believe that nudibranchs’ gaudy colors warn predators of these potent weapons.

By night, rays forage two to three feet above sandy bottoms or nearby reefs. They slowly drift over unsuspecting fishes and stun them with an electrical charge. As the electric organ discharges, the ray wraps its disc around the prey to concentrate the electric field and also to manipulate the fish to be eaten whole (head first). During the daytime, rays rest snuggled in sandy or muddy bottoms, but they’re awake enough to quickly stun and devour a fish that swims within jolting distance.

mantle

To touch a gumboot is to feel the fuzzy texture of about 20 species of red algae that live on the mantle and give the gumboot its brick-red color. The gumboot also eats red algae, which probably adds to its color as well.

The gumboot uses its tonguelike radula to scrape algae from rocks. The radula has many tiny teeth capped with the element magnetite; the teeth contain so much magnetite, in fact, that a magnet can pick them up.

When the rocks are wet, limpets move about, grazing on diatoms (microscopic plants) layered on the rocky surfaces. When the rocks are dry, limpets must take action to conserve moisture. They return to their homesites, where they snuggle in by clinging tightly with their muscular feet.

As long as the crab stays in the neighborhood, it blends in and looks at home. Crabs that have grown large enough to defend themselves don’t decorate their backs; however, plants and animals settle there without help, take hold and grow.

Young cancer crabs are often found clinging to this jelly, even inside the gut. The crab helps the jelly by eating the parasitic amphipods that feed on and damage the jelly.

But in all their variety—from flat platelike colonies to pillowlike clumps to the branching, antlerlike form from which they get their common name—these fast-growing corals are consummate reef builders and important members of coral reef communities around the world.

pelvic

A clingfish's suction cup does double duty. When the tide goes out, a clingfish's pool might be left high and dry. But the cup holds in moisture, so the fish can still breathe. Tucked safely beneath its rock, the clingfish waits until the tide rolls back in again.

But blacktips aren't as menacing as they seem. They're curious about divers in their territory, but they're also wary and easily frightened. These small sharks hunt the abundance of fishes that live on the reefs and try to steer clear of people.

At home on reefs throughout the Indian Ocean, the South Pacific and parts of South Africa, giant clams live on shallow reef flats down to depths of around 66 feet (20 m). Below that, the algae they depend on to survive wouldn't have enough sunlight to grow.

The large anemones often host communities of other animals as well. Certain shrimp and crabs live on anemones, and a single anemone may be home to several kinds of anemonefishes.

Anemonefishes need the protection they find in their anemones: the anemones' stings keep fish predators at bay, and an anemonefish never lives without its host anemone. The partnership may benefit the anemones, as well. They get scraps of food dropped by the anemonefishes as they eat. And the aggressive and territorial anemonefishes may defend their anemones by driving away butterflyfishes and other anemone-eating fishes.

Sheephead hunt actively during the day, but at night, as many wrasses do, they move to crevices and caves and wrap themselves in a mucus cocoon. Predators on the hunt can’t detect the fishes’ scent through the mucus covers. Sheephead appear to be asleep, but since fishes don’t have eyelids, we can only assume they’re sleeping.

cephalopods

radula

To avoid predators by day, a nautilus lingers along deep reef slopes, some as deep as 2,000 feet (610 m). At night, a nautilus migrates to shallower waters and cruises the reefs, trailing its tentacles in search of food.

A nautilus swims using jet propulsion—it expels water from its mantle cavity through a siphon located near its head. By adjusting the direction of the siphon, a nautilus can swim forward, backward or sideways.

These small, elusive sharks prefer shallow waters less than 40 feet deep. They spend their days hiding under ledges, in caves or among kelp and other seaweeds; they hunt at night. Horn sharks feed on seafloor invertebrates, especially sea urchins and crabs, and occasionally on small fishes.

The horn shark’s average length is just over three feet, and it’s named for its large fin spines.

A cabezon’s life cycle takes it offshore and back. Adults spawn on rocky outcrops, and males guard the eggs until they hatch. The larval young drift out to sea, then develop into small, silvery fish that often hide under mats of drifting kelp. As they grow older, the fish settle into tide pools, then move to reefs and kelp forests.

The fragile pink urchin is an abundant sea urchin off our coast. It may go for long periods without food, surviving on stores of fat.

Scientists aren’t sure why pom-pom anemones change shape and roll around––they might be looking for “greener pastures,” where there’s more food to eat.

When a light shines on a catshark’s eyes, they glow—much like a cat’s eyes do. That’s because cats and sharks have special light-sensitive eyes designed for hunting in near-darkness. A catshark is always on the prowl. When a fish or squid swims nearby, the catshark lunges with its mouth wide open—and makes a quick meal of its prey.

Big skates hide in the sand and mud along the seafloor, with only their eyes protruding. Their gray, mottled bodies blend into the background of the seafloor; this camouflage protects them from predators like sharks.

Hagfish live in burrows on the seafloor and locate their food by smelling and feeling as they swim. They prey on small invertebrates living in the mud, as well as scavenging dead and dying fish. They are noted for their unusual way of feeding—they slither into dead or dying fishes and eat them from the inside out, using their "rasping tongue" to carry food into their funnel-shaped mouth.

Hagfish are notorious for their defensive slime. They secrete a sugar and protein matrix into the seawater. When expelled, it mixes with the saltwater and becomes a slippery slime. Protein strands within the slime make it extremely sticky.

This crab has clutching claws and fast-moving mouth parts—they help the crab grab food, tear it apart and shovel the pieces into its mouth.

A mysid might seem like an easy meal for a hungry fish with big teeth. But this shrimplike animal packs a secret weapon. When a fish threatens to eat it, a mysid spits out glowing fluid. The sudden flash of light distracts the attacker and gives the mysid time to swim away.

These jellies are very active swimmers. They change their swimming speed by changing the intensity of their bell contractions and can swim at a pace of about 60 feet (18 m) per hour.

These shrimp have light-producing organs on the undersides of their translucent, red-and-white bodies. Their blue glow matches the color and intensity of dim light from above. This “counterillumination” hides the shrimp from predators looking up from below.

When a fish or shrimp swims nearby, a fangtooth simply opens its big mouth and sucks the animal inside. Animals caught in its trap have little chance of wriggling free.

Hatchetfish can regulate the intensity and color of light from these organs to match the light filtering down. Each species of hatchetfish has its own particular pattern of lights.

This use of bioluminescent light is called "counterillumination," a common adaptation in midwater fishes and cephalopods. Some midwater predators hunt by looking up for the silhouettes of animals. Counterillumination makes hatchetfish almost invisible from below.

The individual animals live along the sea fan’s "branches," and look like little anemones. Using small, feathery tentacles, a sea fan feeds by capturing tiny animal plankton that drift by in the currents.

Squat lobsters also hide under rocks to protect their bodies. Safe from hungry fishes, they wait for snacks to settle nearby—those claws are perfect for reaching out and picking up food.

Along with curling up in crevices and hiding under rocks, squat lobsters stake out their territory on sandy patches. They use their claws to scoop up sand and sift for sunken snacks.

An eelpout isn't really an eel; it just looks like one, with its long, thin body. It’s frequently seen curled up into an "O"—scientists think eelpouts might be disguising themselves as a jelly to avoid being eaten. Midwater eelpouts were first discovered in Monterey Bay.

Rockfish live in a variety of habitats. Some live on rocky reefs or seafloors in nearshore shallow waters. Others live on the deep seafloor or in the water column. In giant kelp forests, rockfish hover motionless under the kelp canopy, buoyed by their air bladders. Some species rest on rocks at the bottom of the kelp forest, with creatures like sea cucumbers and abalone.

If you’ve ever seen a Venus flytrap capture an insect, you have a clue as to how a predatory tunicate eats. Its mouthlike hood is quick to close when a small animal drifts inside. Once the tunicate catches a meal, it keeps its trap shut until it’s ready to eat again.

In Oneirodes, the males are free-living but much tinier than the females, and they lack teeth. Males have extremely large nostrils and a powerful sense of smell, which they use to locate females. The females apparently release a special chemical that males can detect and follow. Such special chemicals are called pheromones.

holdfast,

(haptera)

(stipe)

canopy

Bull kelp is an annual seaweed—meaning it grows from a spore to maturity within a single year. It grows quickly, sometimes 10 inches (25 cm) in one day. Bull kelp reproduces by spores in spore patches (sori), which are heavy enough to fall to the ocean floor. This ensures that spores settle close to parent plants and on suitable substrate. Winter storms wash spent bull kelp onto beaches where the plants dry and turn brown. They have the appearance of bull whips, giving this kelp its common name.

Giant green anemones are often solitary and exhibit aggressive territorial defense against rival anemones; in some locations, however, there can be up to 14 green anemones per three square feet.

Some fishes develop resistance to the giant green anemone’s sting by covering themselves with mucus.

Monkeyface-eels’ body shapes allow them to live hidden in crevices and holes in rocky reefs, rocky tidal zones and kelp forests. These fish don’t move around much, seldom traveling more than 15 feet (4.6 m) from their home. They can breathe air and, in a moist area, can stay out of the water for at least 35 hours.

Many monkeyface-eels live close to shore. Tidepoolers turning over rocks are likely to see a monkeyface-eel scurry away. Experienced tidepoolers know it’s important to return rocks to their original positions so animals can return to their homes.

The California mussel attaches to rocks by fibers called byssal threads. These threads are produced in liquid form by the byssal gland. The liquid runs down a groove formed by the foot. When the foot pulls back, exposing the liquid to sea water, the liquid solidifies into a thread. A large mussel moves by breaking old threads, then attaching new ones to another spot; a small mussel creeps around on its foot.

Rockfishes cluster just above the reef. If a hungry fish or seal comes by, the rockfishes duck between the boulders. But mostly they just hang there, snacking on the smaller fishes, octopuses and shrimp living among the rocks.

Those batlike wings also serve in the hunt for food. Bat rays flap their pectoral fins in the sand to expose buried prey, like clams. Rays also use their lobelike snouts to dig prey from sandy bottoms. The resulting pit can be up to 13 feet (4 m) long and eight inches (20 cm) deep—an important source of “leftover” small prey for fishes that can’t dig. Bat rays have one to three venomous barbed spines at the base of their long tails, but these docile animals sting only to defend themselves.

Bat ray teeth are fused into plates that can crush the strongest clam shells. The rays crush the entire clam, or other molluscs, inside their mouths, spit out the shells, and then eat the soft, fleshy parts. If a tooth breaks or wears out, a new one replaces it. Rays grow new teeth continuously, like their shark kin.

There are no commercial fisheries along the California coast, but commercial fishing exists in Mexican waters, where bat rays are a food fish.

For many years, oyster growers trapped bat rays because they thought bat rays ate large numbers of oysters. But recently researchers have discovered that bay rays rarely eat oysters, and that crabs were destroying the oyster beds. The oyster growers were actually causing the destruction of their own oyster beds by trapping bat rays, which eat crabs.

Fortunately, a star can't be tugged out by the arm. The arm snaps off, and a new one grows from the stump. At night, they stretch out to catch food particles, passing the bits down to the central mouth

When a predator like the barber slug comes by to clip off its tentacles, the anemone retreats quickly down the tube—sometimes pulling the slug in with it! Luckily, an anemone's tentacles grow back after an attack.

A male shiner surfperch changes color with the seasons. Come summer, he covers his shiny silver and yellow stripes with a darker suit of courtship colors.

Curlews breed in grasslands and dry open prairies in the western United States and southern Canada. The nest is a scrape in the ground lined with grass, weeds and plant stems. Their clutch size is about four eggs. After the chicks hatch, the adults lead them to areas of denser grass, where they feed mostly on grasshoppers.

A mouth located on the bottom of the disc is well placed for eating bottom dwelling prey, but breathing through it would destroy a guitarfish’s delicate gills. Instead, guitarfish pump water in through holes (spiracles) on top of their heads, over the gills, and out through gill openings on the bottom of the disc.

Guitarfish lie in ambush buried in the sand with only their eyes sticking out, waiting for an unwary crab or flatfish to wander by. Suddenly the sand erupts, and the guitarfish gulps down its meal. At night, they leave the sand to actively cruise the seafloor to feed on crabs, worms, clams and, perhaps, fishes.

phytoplankton

Cope is greek meaning an “oar” or “paddle;” pod is Greek for “foot.” Copepods have antennae and appendages that are used like paddles for movement. Some species swim in a jerky fashion, while others move more smoothly.

Established coastal sand dunes guard the coast against storm waves that could flood the land beyond the dunes. Conditions here are harsh for plants; few nutrients, almost no water, extreme temperature changes and blowing sand characterize dune habitats. But dune grass’s special adaptations make survival possible—its thick, shiny leaves prevent loss of water and also reflect drying sunlight.

The first colonizers of newly formed sand dunes must grow and establish themselves before the sand shifts beneath their "feet." American dune grass is one of these important pioneer plants. It has long, underground stems (rhizomes) that send shoots upward and roots downward. These rhizomes anchor American dune grass and the surrounding shifting sand, creating places where other dune plants can survive.

Muscular pectoral fins enable this shark to "walk" along the seafloor. When disturbed, instead of swimming out of danger, it sometimes quickly "runs" away.