Glossary

abdomen: the belly region of a vertebrate animal, or the hind segment of the body of an insect, crustacean or other arthropod.

abyss: a very deep region.

abyssal plain: the flattened floor of the deep ocean offshore from the continental margin.

abyssal zone: the deep sea region below 13,000 feet (4,000 meters).

adaptation: a characteristic body part, shape or behavior that helps a plant or animal survive in its environment.

aerobic: containing oxygen or requiring oxygen.

albatross: a large seabird that spends much of its life wandering over the open ocean far from land.

algae: a large group of primitive plants that live mostly in water. Kelp and other seaweeds are algae. Algae have simple bodies–many kinds exist as single cells.

algin: a slippery substance extracted from brown algae, including kelp. Algin is used in paint, toothpaste, ice cream and many other products because it thickens liquids and binds oily and watery liquids together.

amphipods: small, shrimplike crustaceans.

anaerobic: not containing oxygen or not requiring oxygen.

anchovies: small silvery fishes that swim in big schools. Anchovies are eaten by tuna, salmon, penguins,and many other predators.

anemone: a sea animal with a crown of stinging tentacles at the top of a fleshy stalk. Often called a “sea anemone.”

angling device: a modified dorsal fin or chin barbel on some deep sea fishes that acts like a rod and bait to attract prey or mates.

anoxic: without oxygen.

antenna: a long, slender organ or feeler located on the head of an insect, crustacean or other arthropod; or any long, slender rod used for gathering or transmitting information.

antibiotic: a medicine which kills disease-causing bacteria.

aquaculture: fish farming.

aquatic: of the water; living in the water.

arthropod: a large group of invertebrate animals with jointed legs, including the insects, scorpions, crustaceans and spiders.

atmospheric pressure: the pressure of the air here on the earth’s surface. At sea level, atmospheric pressure equals 14.7 pounds per square inch (2.6 kilograms per square centimeter). This amount of pressure is known to scientists as one atmosphere. People and other land animals are adapted to one atmosphere of pressure and thrive on the earth’s surface. But water is much heavier than air, and as we dive into the ocean, pressure increases. Divers feel an extra atmosphere’s worth of pressure with every 33 foot (10 meter) increase in depth.

atoll: a ring-shaped coral reef that forms around a volcanic island.

aviary: an enclosure where birds can fly around freely.

avocet: a shorebird with long legs and a very long, upward-curving bill.

bacteria: one-celled organisms so small they can only be seen with a microscope. Some bacteria cause diseases, like pneumonia and tuberculosis, but others are necessary to all life on Earth because they break down dead organic material.

baleen: a tough, horny material growing in comblike fringes from the upper jaws of some species of whales.

barbel: a long, slender organ extending from the chins of some fishes, sometimes used as a lure to attract prey.

bamboo sharks: sharks of the genus Chiloscyllium, which live in shallow waters around coral reefs and have bamboo-like markings when young.

Banggai cardinalfish: a tiny coral reef fish with large eyes and patterned skin, found mainly near the island of Banggai (near Indonesia).

barnacle: an invertebrate animal that lives in a hard shell attached to a rock, boat bottom or other hard surface. Barnacle shells are cone-shaped, like tiny volcanoes. Barnacles are crustaceans, related to crabs, shrimp and lobsters.

bathyl: the deep sea region between 600 and 6,000 feet (183 to 1,830 meters).

bat ray: a species of ray which has long fins that look like bat wings.

beaches: sections of the coastline composed of sand, pebbles, shells, or cobble.

beach hoppers: tiny, shrimplike animals that live among piles of kelp washed up on beaches; they hop like fleas to get away and are sometimes called “sand fleas.”

bell: the round, non-stinging part of umbrella-shaped jellies, known as medusas.

bends: “the bends” is a painful condition caused when nitrogen gas forms bubbles in a diver’s blood. Scuba divers risk getting “the bends” if they come up too fast from a deep dive.

benthic: on or near the bottom of a lake, river or ocean.

benthic echinoderm: a sea star, sea urchin or other echinoderm that lives on or near the seafloor.

benthic jelly: a jelly that lives on or very near the seafloor.

benthic mollusc: one of a group of soft-bodied animals that live on or near the seafloor. deep sea snails and clams are benthic molluscs.

beta carotene : a natural yellow pigment, present in many vegetables and extracted from green algae.

bioluminescence: light made by a living organism.

black-necked stilt: a shorebird with a dark back and long red legs.

blooms: Jelly blooms are the result of reproduction events where, in its asexual stage, jellies bud multiple polyps, and these polyps divide. Itís thought that blooms of jellies occur when waters are overfished or when a species is accidentally introduced into an environment and begins to take over.

blubber: a thick layer of fat under the skin of whales, seals and their relatives. Blubber helps keep these marine mammals warm.

bluefin tuna: a group of tuna species with iridescent blue skin. Bluefin are some of the ocean’s biggest, fastest predators. They live in cold water and can weigh up to 2,000 pounds (907 kilograms).

blue-spotted boxfish: a small tropical fish with a square, boxlike body. The “box” is stiff body armor made of stuck-together scales.

bonito: a sleek, fast-swimming fish in the tuna family.

bray:a loud call of blackfooted penguins and others in the genus Spheniscus. Penguins bray when mating or defending territory.

brittle star: a sea star that has a small central body surrounded by many long, brittle arms.

budding: The process by which young jellies, called polyps, produce identical polyps.

buoy: a floating object anchored in place. Buoys are often used to hold equipment for measuring air temperature, water temperature, wind speed or salinity.

burrower: an animal that digs a hole to live in.

butterflyfish: a member of a large family of colorful coral reef fishes with flattened bodies and small mouths.

bycatch: fishes or other animals caught by accident in fishing gear; species that the fishers don’t want to catch. Bycatch is usually thrown back dead or dying. Bycatch is also called “bykill” or “wasted catch.”

cacophonous: loud and noisy.

caerulean damselfish: a small, bright-blue coral reef fish found in the Pacific and Indian Oceans.

camouflage: colors or patterns that make something hard to see. Many animals use camouflage to hide from their predators.

canopy: the top part of a forest. In the kelp forest, the canopy is the top layer where kelp fronds float on the surface.

canyon walls: the sides of a canyon. Canyon walls can be steep or gently sloping. Many benthic organisms live on the walls of Monterey Canyon.

capelin: a small schooling fish from the Arctic and northernmost parts of the Pacific Oceans. Predatory fishes and whales eat capelin.

carrageenan: an edible substance extracted from red algae, used as a thickener in foods, cosmetics and other products.

carnivore: an animal that eats other animals.

carp: a freshwater fish with large scales and small barbels near its mouth. Carp have been raised as food by people since ancient times.

cartilage: tough, flexible tissue (like the tissue at the tip of your nose) which forms the skeleton of sharks, skates and rays.

catfish: a member of a group of fishes with smooth skin, large flat heads, and long barbels near the mouth. There are both marine and freshwater catfishes. Some of the freshwater species are raised easily in ponds.

cavort: to jump around merrily; to caper.

cephalopod: a member of the group of molluscs that includes octopuses, squid, nautiluses and cuttlefishes. Cephalopods all have many arms and well-developed eyes.

cetacean: any member of the group of marine mammals that includes whales, dolphins and porpoises.

chameleon: a lizard that can change color to match its background.

channel: the deepest part of a stream or harbor, where most of the water flows.

charade: movements that are meant to trick or deceive.

chemoreception: the ability to sense chemicals in the environment.

chemosynthesis: the process by which some bacteria use chemicals (like hydrogen sulfide) to provide the energy they need for life.

Chilean sea bass: a fish that lives in the deep sea near Chile. This species was called “Patagonian toothfish” until fish sellers decided it needed a name that would sound better to seafood buyers. This slow-growing species is in serious trouble from overfishing.

chlorophyll: the green chemical that lets plants turn sunlight into energy through the process called photosynthesis.

chordates: a group of animals (phylum Chordata) which have, at some time in their development, a notochord, gill slits and a dorsal nerve cord. Chordates include vertebrates and tunicates.

clam: a mollusc that lives between two flattened shells.

class: in biology, a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species). Class is the category that ranks below a phylum and above an order.

cleaner wrasses: small fishes of the wrasse family that pick parasites off larger fishes.

cod: a large fish that often lives close to the seafloor. Cod have firm white flesh; for centuries, cod have been important to people of many nations as a food fish.

coelenterate: any of the various invertebrate animals of the phylum Cnidaria, characterized by a radially symmetrical body with a saclike internal cavity, and including the jellyfishes, hydras, sea anemones, and corals.

cold seep: a habitat on the deep seafloor where cold fluids seep from the rocks. These fluids contain chemicals (sulfides and/or methane) that bacteria use as their energy source. Cold seep habitats support communities of animals that rely upon this bacteria for food, and are therefore part of a food web based on chemicals instead of sunlight.

community: all of the plants and animals living in a specific area (habitat), often described by the most abundant or obvious organisms. The kelp forest community means all the animals and plants that are part of the kelp forest.

conservation: the practice of protecting nature from loss or damage.

continental crust: the earth’s crust that includes both the continents and the continental shelves.

continental margin: the ocean floor from the shore of a continent to the abyssal plain.

continental rise: part of the continental margin; the ocean floor from the continental slope to the abyssal plain.

continental shelf: the submerged shelf of land (often <200 m) that extends from land to the shelf break at the continental slope.

continental slope: part of the continental margin; the ocean floor from the continental shelf to the continental rise or oceanic trench, usually to a depth of about 660 feet (200 meters).

copepod: a member of a large group of species of tiny shrimplike crustaceans.

coral: a group of invertebrate animals related to sea anemones. Individual coral animals have soft bodies topped by a ring of stinging tentacles for catching food. Some kinds of coral build hard limestone skeletons; when they die, other corals build on top until a great reef is formed.

corrugations: rows of ridges.

crab: a crustacean with a rounded thorax, a short abdomen tucked under its body, and, in most species, large front claws.

craggy: rough; full of cracks and ridges.

creche: a group of youngsters, all about the same age, who stay together for protection.

crustacean: an invertebrate animal with a hard shell and many jointed legs. Shrimp, crabs, lobsters and crayfish are crustaceans.

crown-of-thorns: a sea star covered with long, thornlike spines; one of the most important predators in the coral reefs.

ctenophore: a marine animal belonging to the phylum Ctenophora, which usually has a transparent, jellylike body and eight rows of comblike cilia (tiny hairs) for swimming.

culture: in biology, this means to raise or grow an organism in a laboratory or other controlled environment.

cuttlefish: a soft-bodied marine animal with many arms, related to octopuses and squid.

data: information, usually expressed as numbers. (“Data” is actually a plural noun. The singular is “datum.” ) Data are often used in analysis to draw conclusions that support or reject a hypothesis.

debris flows: relatively slow movement of sediments downward over gently sloping terrain.

decomposer: an organism, like a bacterium, that causes the decay of dead plant and animal matter.

deep scattering layer: a concentrated layer of midwater organisms that can reflect and scatter sound waves produced by sonar devices.

deep sea: >1000 m deep, lower region of the ocean where sunlight does not penetrate.

delegate: (noun) a representative who speaks for a group of people at a meeting or lawmaking assembly. (verb) To give someone authority or responsibility to carry out a task.

deposit feeder: an animal that eats organic matter that’s been deposited on or in the seafloor.

depth sounder: an electronic device that measures the depth of water very precisely.

device: an instrument, tool or machine designed and constructed to perform a certain task.

display: a set of calls or motions done by a bird or animal to convey a particular message. Penguins might do a courtship display to attract a mate, or an aggressive display to warn off an enemy.

diurnal: daily.

dogfish: a species of small shark.

doliolid: a deep sea pelagic tunicate.

dolphin: a member of a group of small whales that have sharp, pointed teeth and pointed snouts.

dorsal: on or toward the back or topside (opposite of ventral).

dragging: another term for bottom trawling, a fishing method in which large nets are dragged along the seafloor to catch fish.

dredge: a net attached to a frame that’s dragged along the ocean floor to collect animals.

drift kelp: a piece of seaweed that breaks free of its holdfast, drifts with the ocean currents and sinks to the seafloor.

dune: a hill of sand. The wind pushes sand from the beach into dunes.

ebb: to flow away. At low tide, water ebbs back into the ocean.

echinoderm: one of a group of invertebrate animals identified by their spiny skin, including sea stars, sea urchins and sand dollars. “Echinos” means spiny; “derma” means skin.

echo sounder: a machine that determines water depth by measuring the time it takes for sound waves to reach the seafloor and bounce or echo back to the surface.

ecology: the scientific study of the relationships between plants, animals and their environment.

ecosystem: the natural system in which energy and nutrients cycle between plants, animals and their environment.

eelgrass: a water plant with long, grasslike leaves. Eelgrass is one of the few flowering plants that lives in salt water.

egret: a wading bird with long legs.

electroreceptor: an organ specialized to detect electric signals. Sharks have electroreceptors that help them find prey.

Elkhorn Slough: a slough (coastal wetland) located about 15 miles (24 km) north of the city of Monterey, California.

El Nino: an unusual, warm surface current that flows out of the tropical Pacific ocean and moves along the Pacific coasts of North and South America.

emulsifier: a substance that lets oil and water mix into a smooth liquid.

encrust: to cover with a layer or crust.

ephyra: A free-swimming young jelly produced when a polyp buds

epipelagic: the upper sunlit ocean layers to 350 feet deep (107 meters), also called the photic zone.

estuary: a coastal area where freshwater mixes with the ocean, often in a partially enclosed area; highly productive habitat with diverse terrestrial and aquatic life.

evolution: the process of gradual change over long periods of time.

extinct: no longer alive; no longer in existence.

eyespots: A jellyís light-sensing organs, usually found around the edge of the bell.

factory trawler: a large ship equipped to catch, clean and freeze fish for market.

family: in biology, a category that’s part of the scientific system for grouping together related plants, animals, and other organisms (kingdom, phylum, class, order, family, genus, species). Family is the category that ranks below an order and above a genus.

fat innkeeper worm: a wormlike invertebrate that burrows in mud; it’s called the innkeeper because many other small animals come to live in its burrow.

fault: a break in the rocks of the earth’s crust along which movement may occur, causing earthquakes.

feather-duster worm: a marine worm that lives in a leathery tube and sticks out a bright orange or purple crown of soft, feathery gills. When disturbed, it pulls the gills into the tube lightning-fast.

feces: solid waste that passes out of an animal’s digestive tract.

feral: wild. Used to describe animals that are usually domesticated, like cats or pigs.

filter feeder: an animal that eats by filtering or straining small particles of food from the water.

fisheries management: the effort to regulate where, when and how people fish, and how many fish they catch, to protect fish populations so that people can continue to fish. Most fisheries management is done by government agencies such as the U.S. National Marine Fisheries Service.

fishery: the organized harvest of a certain species of fish or shellfish. We speak of “the Monterey Bay squid fishery” to mean all the squid caught in Monterey Bay.

fishes: cold-blooded aquatic vertebrates covered with scales and move using fins.

fishing pressure: the amount of fishing for a certain species of fish or shellfish. If there’s heavy fishing pressure on sharks, it means that lots of sharks are being caught by fishers.

flatfishes: a general term for fishes like flounder, sole and halibut that are flattened for life on the seafloor.

flat porcelain crab: a small crab with a smooth, shiny shell that lives in the intertidal zone.

flounder: a fish with a flattened body adapted for life on the seafloor.

flukes: the flat tail flippers of a whale or other marine mammal.

food chain: the relationship between plants and animals that shows who eats what. Energy is transferred from one organism to another through the food chain.

frond: a long, feathery leaf, or the leaflike blade of a kelp plant or other sea plant.

fungal: having to do with a mold, mushroom or other fungus.

garibaldi: a bright-orange fish that lives in warm waters, including the kelp forests off southern California.

gas bladder: a gas-filled sac found in many fishes. Gas bladders help provide buoyancy; they’re also called swimbladders.

gastropod: a group of molluscs that travel on a single, muscular foot and often secrete a one-piece shell for protection. Snails, slugs, limpets and abalones are all gastropods.

genus: in biology, a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species). Genus is the category that ranks below a family and above a species.

geology: the scientific study of the EarthÕs rocks and minerals, including the Earth’s crust and interior.

gill: an organ that an animal uses to breathe under water. Gills absorb oxygen from the water.

gill covers: the tough flaps of tissue that cover a fish’s gills.

gill net: a type of fishing net that catches fish by their gills or gill covers.

global positioning system (GPS): an electronic system that uses signals from satellites to locate things far below on the surface of the earth or ocean. GPS technology is being used to make very accurate new maps of the earth and ocean. GPS devices let scientists and fishers find their way very precisely.

godwit: a long-legged shorebird with a very long, straight bill.

golden-eye mysid: a shrimplike animal that lives on the seafloor. The golden-eye mysid was named for the way its eyes reflected the lights of remotely operated vehicles (ROVs) exploring the deep sea.

gorgonian: a member of a group of corals that grow in treelike shapes; some live in cold, deep water and grow very slowly.

guano: the droppings of birds or bats. In some places, like penguin colonies, huge deposits of guano build up over many years. People sometimes harvest this guano to use as fertilizer for farms and gardens.

guitarfish: a flattened fish in the shark family, not quite as flat as a skate or ray.

gullet: the throat.

habitat: an organism’s home; for example: in the midwater, on the seafloor, near the surface or in a tide pool.

hadal: the deep sea region below 20,000 feet (6,100 meters); the deep trenches.

hake: a fish, related to cod, that gathers in large schools. Hake live from the surface down to depths of 3,000 feet (914 meters).

halfmoon: an oval-shaped fish with a tail curved like a crescent moon that lives in nearshore waters along the Pacific coast of North America.

halibut: a large fish with a flattened body adapted for life on the seafloor.

haptera: rootlike structures growing from the base of a kelp plant. Haptera form the holdfast that anchors the kelp to the seafloor.

harlequin shrimp: a colorful shrimp from the coral reefs of the central Pacific.

haul out: to climb up out of the water. Seals often haul out onto rocks.

head of the canyon: the shallow part at the beginning of an underwater canyon.

herbivore: an animal that eats plants.

hermaphrodite: an animal or plant with both male and female sexual organs.

hermit crab: a crab that protects itself by living inside an empty snail shell. There are many species of hermit crabs, some on land, some in the ocean.

herring: a small, silvery fish that swims in large schools.

holdfast: the rootlike part of a kelp plant that anchors the plant to the seafloor.

hook and line: any fishing method which uses a sharp hook (baited or not) attached to a nearly-invisible fishing line. Different hook-and-line methods include longline, troll and pole-and-line.

horizontal: side-to-side, or stretched out flat like the horizon (opposite of vertical).

humus: nutrient-rich earth formed when plant material decays.

hydrodynamics: the study of fluids in motion and the movement of objects through fluid.

hydroid: a body shape often taken on by animals related to sea anemones. A hydroid has a fleshy central stalk topped by a ring of tentacles used for catching food. Anemones are one kind of hydroid; many jellies are hydroids for part of their lives.

hydrothermal vents: breaks in rocks where warm or hot fluids seep out.

hypothermia: a dangerous loss of body warmth, which can cause death.

hypothesis: a scientific idea about how something works, before the idea has been tested. Scientists do experiments to test their hypothesis and see if the hypothesis is correct.

ichthyology: the scientific study of fishes.

inland: away from the ocean, on dry land.

intertidal zone: the area along shore that is covered by water at high tide but is exposed to the air at low tide.

introduced predator: a non-native predator, introduced to a habitat through human activity.

invertebrate: an animal without a backbone.

iridescent: gleaming and flashing with many colors, like a peacock feather or a soap bubble.

jellies: also called jellyfish, these are drifting sea animals with a soft central disk and long stinging tentacles. Jellies are related to coral and sea anemones.

kelp forests: formed by large brown macroalgae in shallow nearshore waters (<30 m deep), it is a highly productive and dynamic habitat with 3-dimensional structure similar to a terrestrial forest.

killdeer: a long-legged bird that lives both near the shore and in meadows far inland.

kilometer: a measure of length equal to 1,000 meters or about 5/8 of a mile.

kingdom: in biology, a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species). Kingdom is the broadest category; plants are in a kingdom separate from animals.

krill: shrimplike crustaceans (mostly of the genus Euphausia) that grow to two inches (5 centimeters) long. Large populations of krill provide the main food for baleen whales and some kinds of fishes.

landed: brought to land, brought to shore; in the case of a fish, caught and brought to land.

landings: landings of fish are the quantities of fish landed (caught and brought to land) by fishers.

landslide: a mass of loosened rocks or earth that slides down a slope or hillside.

larva: the young and immature form of an animal, which must change to become an adult.

leopard shark: a species of shark whose skin is marked with dramatic dark spots or blotches.

light absorption: the dimming of light as it passes through water or any other substance.

limpet: a group of gastropod molluscs, related to snails, which have simple shells shaped like a bowl or platter.

lingcod: a long-bodied fish that lives in cold Pacific waters.

lobster: a crustacean with a long abdomen and, in most species, large front claws.

longlining: a type of commercial fishing that uses hundreds of baited hooks on a line that can be many miles long.

mackerel: a sleek silvery-blue fish with stripes on its back, which swims in large schools. Mackerel are related to the tunas.

mahi-mahi: a large fish that lives in the open ocean in warm parts of the world.

mammal: a warm-blooded animal that breathes air, has hair and feeds its young with milk.

maneuver: to control the movement and direction of something, as to maneuver a vehicle.

mangrove: a small tropical tree that grows in wetlands at the edge of the ocean. Mangrove forests are habitat for many kinds of fishes and other animals.

mantle: a portion of the body wall of a mollusc. In snails, clams and other molluscs with shells, the mantle secretes the shell. In octopus and squid, the mantle is the outside of the body.

marine: of the sea.

marine betta: a small, spotted fish found on coral reefs of the western Pacific.

marine mammals: large vertebrates that primarily live in the ocean or depend upon the ocean for survival, includes cetaceans, pinnipeds and otters.

marine snow: organic particles that fall into the deep sea from the sunlit surface waters.

marsh: a wetland where plants grow with their roots in water and their tops in the air.

marsh wren: a small songbird that nests in marshes.

medusa: The umbrella-shaped type of jelly.

mesoglea: The layer of gelatinous material that separates the inner and outer cell layers of a coelenterate.

mesopelagic: the twilight midwater zone 660 to 3,300 feet deep (200 to 1,000 meters), between the upper sunlit zone and the dark ocean depths.

mesotech sonar: a device on a remotely operated vehicle that’s similar to an echo-sounder and shows the bathymetry (hills and valleys) of the seafloor.

meter: a length of measurement equal to 39.37 inches, or about three feet.

methane: a colorless, odorless gas formed naturally by the decomposition of organic matter.

microscopic: so small that it can only be seen with a microscope.

midden: a pile of trash left over from the kitchen or dinner table.

mid-oceanic ridges: elongated rises on the ocean floor where molten rock periodically erupts, forming new oceanic crust.

midwater: a habitat in the deep sea, usually defined as the waters between the sunlit surface and the deep seafloor.

mole crab: a small crab that lives buried in sand at the ocean’s edge; also called the sand crab. Mole crabs can dig very fast to escape from predators.

molt: to shed old feathers or hairs so that new ones can grow. Birds molt every year; so do elephant seals.

monitor: (verb) to check or gather information. (noun1) A person who checks or gathers information. (noun2) A screen for viewing information, such as a computer monitor.

monkeyface-eel: a fish with a long, eel-like body that lives in holes between rocks along the Pacific coast of North America.

monkfish: a fish with a wide mouth and a long, tapering body that lives on the seafloor in the same habitat as Atlantic cod.

Monterey Bay: a place along the central California coast about 120 miles (190 km) south of San Francisco.

Monterey Canyon: an underwater canyon just offshore in Monterey Bay. Monterey Canyon is about as big and as deep as the Grand Canyon of Arizona. The canyon begins just offshore near the town of Moss Landing and stretches 60 miles (100 kilometers) out to sea. It slopes down from a depth of 60 feet (18 meters) to more than 12,000 feet (3,656 meters) deep.

moon snail: a species of marine snail that has a large, pale, rounded shell.

mooring: a fastener or anchor.

morphology: the scientific study of the form and structure of living organisms; or the form and structure itself.

mudflat: a flat area along the coast, covered with a thick layer of mud or sand. Mudflats are usually under water at high tide.

mussel: a mollusc similar to a clam but with narrow, dark-colored shells.

nautilus: a soft-bodied marine animal with many arms and a spiral shell. Nautiluses are related to octopuses and squid.

nematocyst: The small organelle in various coelenterates, as jellyfish, that when stimulated ejects a coiled tube that chemically paralyzes its victim. It is located inside the stinging cell (cnidoblast).

notochord: a long, flexible rod which runs the length of the back in some kinds of animals (animals that belong to the phylum Chordata). In vertebrates, the notochord develops into part of the backbone.

nudibranch: a sea slug; member of a group of snails without shells that breathe through long, feathery gills on their backs.

nutrient: a chemical ion or compound that promotes growth or provides energy to a living organism.

observation: a part of the scientific process where something is noticed by using one of the five senses: hearing, tasting, touching, smelling or seeing.

oceanic trench: deep, steep-sided depression in the ocean floor, formed when one plate of the earth’s crust is pushed beneath another plate.

oceanography: the scientific study of all aspects of the physics, chemistry, geology and biology of the world’s oceans.

ochre star: a yellowish sea star that lives in the intertidal zone.

octopus: a soft-bodied marine animal that has eight arms covered with suction discs. Octopuses are related to squid and cuttlefishes.

omnivore: an animal that eats both plants and animals.

opaleye: an oval-shaped fish with blue eyes that lives in nearshore waters along the Pacific coast of North America.

opportunist: an animal that eats almost any plant or animal that comes its way.

oral-arm: Dangling structures a jelly uses to transfer food from its tentacles to its mouth; also called a palp.

orange roughy: a bright orange fish that lives in the deep sea near Australia and New Zealand. Orange roughy grow very slowly–the orange roughy sold for people to eat may be 50 to 80 years old.

orca: a black and white whale that hunts in packs; also called the killer whale. Orcas are actually the largest member of the dolphin family.

order: in biology, a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species). Order is the category that ranks below a class and above a family.

organism: a living thing–a plant, animal, bacterium or other life form.

organic: from a living thing or organism; originating in nature rather than being made artificially.

overfishing: catching too many fish; fishing so much that the fish cannot sustain their population. The fish get fewer and fewer, until finally there are none to catch.

oxygen: a colorless, odorless, tasteless gas. Most life on earth requires oxygen to live. Animals breathe oxygen out of the air or water. Plants also need oxygen, even though they produce oxygen by photosynthesis.

oxygen minimum layer: a zone in the deep sea, usually around depths of 2,000 to 2,950 feet (600-900 meters) where oxygen reaches its lowest level. A special community of organisms is adapted to live in this habitat.

palp: Another word for oral-arm.

parasite: a plant or animal that lives in or on another plant or animal and obtains nourishment from it.

parrotfishes: a group of coral reef fishes with strong beaks for crunching coral.

PDF: short for Portable Document Format. PDF is a universal file format that preserves all of the fonts, formatting, colors and graphics of any source document, regardless of the application and platform used to create the document. PDF files are easy to share between different computers.

pectoral: at the shoulders. The first pair of fins behind a fish’s head are called pectoral fins.

pelagic: of the open ocean; living in the water column, rather than near the seafloor.

pelvic: at the hips. The pair of fins at the back of a fish’s body are called pelvic fins.

perch: a name for a fish with a rounded body; the common name of “perch” is given to many different and unrelated species of fish around the world.

pH: a measurement of how much acid is in a substance.

photic zone: the upper sunlit ocean layers to 350 feet deep (195 meters), also called the epipelagic zone.

photophore: a body organ that makes light.

photosynthesis: the process by which green plants use energy from sunlight to produce sugar and oxygen from carbon dioxide and water. The plants capture the sun’s energy with the green chemical chlorophyll.

phylum: in biology, a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species). Phylum is the category that ranks below a kingdom and above a class.

phytoplankton: tiny, floating plants and other kinds of microscopic green organisms that drift with ocean currents and use the sun’s energy to make food.

pickleweed: a small terrestrial plant that lives close to the sea; it can grow in salty soil that would kill most other land plants.

pilings: long, heavy timbers or beams that support a wharf or bridge.

pinniped: a member of the group of sea mammals that includes seals, sea lions and walruses.

pipefishes: a group of small, slender fishes, related to sea horses.

planktivore: an animal that eats plankton.

plankton: plants and animals (mostly tiny) that swim weakly, or not at all, and drift with ocean currents. Plankton are an important food source for many organisms that live in the sea.

plate: in geology, a big piece of the earth’s crust. The earth’s crust is broken into many plates, which move very slowly as they float on molten rock deep below. Where plates meet, they bump and jostle, giving rise to earthquakes. When one plate is pushed beneath another, mountains, trenches and volcanoes form.

plumage: the feathers of a bird.

pod: a pod of marine mammals is a group of animals traveling together.

pollock: a fish related to cod, heavily fished by people for food. Pollock are made into fish sticks and imitation crab meat.

pollution: degradation of the natural environment by chemicals, oil, trash or other substances.

polyp: A young jelly that results from the joining of sperm and egg; a polyp attaches to a surface and produces identical copies of itself or ephyra.

polyp: any sea animal with a fleshy stalk and a crown of tentacles; coral animals are polyps and so are sea anemones.

porpoise: a member of a group of small whales that have spade-shaped teeth and rounded snouts.

prawn: a shrimp or shrimplike crustacean.

predator: an animal that kills and eats other animals.

preen: to groom and arrange feathers. A bird preens its feathers to keep them clean and in good working order.

prey: an animal that is killed and eaten by a predator.

process: a series of actions that bring about a result. Scientific process involves making observations, formulating hypotheses, designing and conducting experiments, collecting data, analyzing results, drawing conclusions and sharing findings with others.

producers: life forms (plants, diatoms, some bacteria) that produce their own food from simple, non-living chemicals. Producers are the basis of all food chains.

protein: a large group of organic compounds that most organisms use in the construction of their bodies. Muscle, skin and many other kinds of living tissue are made at least partly of protein. Many animals need protein in their diet.

purse seine: a type of fishing net used to surround and catch large schools of fish. The net pulls shut at the top and bottom and looks like a bag or purse.

puffer fishes: a family of small fishes that puff into a ball when threatened.

QuickTime: computer software that makes it possible to view movies, video clips, animations and other special media from a web page.

quintessential: ultimate; the finest example of something.

radula: a rough tongue or band of horny teeth used by snails and other molluscs to scrape algae or bore into shells.

Rathbunaster: a deep sea star with many arms that dwells on the seafloor.

raucous: loud and noisy.

ray: a fish related to sharks and skates, which bears live young and has a cartilaginous skeleton, a broad flat body and a blunt snout.

raze: to destroy or tear down.

red snapper: a fish with red sides, popular with people as a food fish. Many red snapper are caught in the Gulf of Mexico. The name “red snapper” is sometimes given to other, unrelated species of fishes, such as Pacific rockfishes.

reef: an underwater structure; something that extends up from the seafloor but does not rise above the surface of the water like an island. Coral reefs are formed from the hard skeletons of coral. There are also rocky reefs, which are piles of rock under water.

reference: (noun) a source of information; (verb) to identify and record a source of information.

refuge: a safe place.

rehabilitate: to restore to health or wholeness.

research: scientific study to find out facts, test models and develop theories about the natural world.

ribbon eel: a fish in the moray eel family, with a long slender body and large feathery nostrils.

rockfishes: a large family of big, wide-bodied fishes, which live for many years and generally produce only a few young per year. More than 60 species of rockfishes live along the Pacific coast of North America.

rockhopper trawl: a type of trawl net equipped with tires or rollers that let the net roll over rocky areas on the seafloor. Rockhopper trawls are very destructive to the seafloor habitat.

root stabilized: held together or held in place by the roots of plants.

ROV: a remotely operated vehicle that dives in deep water to videotape or collect deep sea animals or other scientific data. An ROV doesn’t carry people–it’s operated from a research ship at the ocean’s surface.

ruddy duck: a species of small duck which lives in coastal areas; males are reddish-brown.

ruddy turnstone: a shorebird with short legs and a reddish-brown back. Turnstones flip over stones to find small invertebrates to eat.

runoff: polluted water that runs from the land or escapes from a pond into a larger body of water.

sablefish: a long-bodied Pacific fish with dark skin and oily flesh. Adults live in very deep water.

salinity: the saltiness of water; sea water is approximately 3.5 percent salt.

salmon: a family of fishes that breed in rivers but live most of their adult lives at sea. Salmon have orange or pink flesh. For centuries, salmon have been important food fish to people of many nations. When they’re ready to breed, most salmon find their way from the ocean back to the same stream where they were born.

salmon run: a population of salmon that breeds in a certain river. Some rivers have several different runs of salmon that breed at different times of the year.

sanddab: a type of small flatfish, caught for food along the California coast. There are several species of sanddabs.

sand dollar: a flattened echinoderm that looks something like an old silver dollar coin.

sanderling: a short-legged shorebird. When sanderlings search for food, they scamper up and down the beach following the waves.

sandpiper: a small shorebird with short legs that searches for food along the sandy shore.

sand star: a species of sea star that lives on the sandy seafloor.

scaleworm: a member of a group of worms with segmented bodies and bristles on each segment; scaleworms and their relatives are some of the most abundant animals in the ocean.

scallop: a mollusc similar to a clam, but with deep ridges in its shell.

scavenger: an animal that eats dead plants or animals or their parts.

sculpin: a family of small fishes that have long bodies, broad pectoral fins, and wide mouths. Many species of sculpins live in the rocky intertidal zone.

sea fan: a member of a group of corals that form delicate, fan-shaped skeletons.

seal: a member of a group of marine mammals that have fur, blubber, and no earlobes on the sides of their heads. Seals are graceful swimmers, but move only clumsily on land.

sea lion: a member of a group of marine mammals that have fur, blubber, and small earlobes visible on the sides of their heads. Sea lions are excellent swimmers but can also move fairly quickly on shore.

sea pen: an invertebrate animal that lives as a colony of individuals arranged in a shape that looks like an old-fashioned quill pen.

sea star: an invertebrate animal, related to sea urchins and sand dollars, with a star-shaped body. Many species of sea star have five points; some have more.

sea turtle: a member of a group of species of turtles adapted for life in the sea. Sea turtles have flipper-like legs and come to shore only to lay their eggs.

seaweed: any of the large plants that grow in the sea, especially marine algae like kelp.

sediment: particles of sand, mud or clay. Layers of sediment often cover the bottom of a body of water.

sensor: a device that receives and responds to a signal or stimulus.

septic tank: a tank buried in the ground where household sewage is gradually decomposed by bacteria. Most houses that are not hooked to a sewer line flush waste into a septic tank.

serpent snail: a snail of the genus Serpulorbis, which makes a shell that twists and turns.

serrated: having a series of scallop-shaped notches along one side. A bread knife often has a serrated edge.

sessile: sitting still; staying in one place. Sessile marine animals are attached at the base and sit in one place on rocks or canyon walls.

sexual dimorphism: a distinct difference in appearance between males and females of the same species.

shale: a soft type of rock that often breaks into big flat pieces. Shale is formed when mud is pressed into rock over millions of years.

shark: a member of a large group of primitive fishes with skeletons made of cartilage. Skates and rays are members of the shark family.

shorebird: a bird adapted to live and find food along the seashore.

shore crab: a small crab that lives and feeds along the seashore. There are several species of shore crabs.

silica: a hard, glassy mineral. Quartz and opal are two forms of silica. Since much sand is made of quartz, silica is very common in sand. Some marine organisms use silica to build their shells.

silt: very tiny particles of mud, sand or clay.

siltation: the process of being covered with a layer of fine mud, silt or sand

siphon: a tube. Clams and many other molluscs breathe through siphons.

siphonophore: A type of jelly thatís made of many smaller members that live and work together as one unit; a colonial jelly.

skate: an egg-laying fish, related to sharks and rays, that has a cartilaginous skeleton, a broad, flat body and a pointed snout.

slough: a marshland or estuary where fresh water meets the sea.

smelt: a small, schooling fish. Many larger fishes eat smelt.

snail: a member of a group of gastropod molluscs; most species secrete a spiral shell for protection. Some species of snails don’t make shells and are known as slugs.

sonar: a system that uses transmitted and reflected sound waves to find objects under water.

spawn: to breed; especially, to breed by releasing eggs and sperm into the water.

species: a particular type of plant, animal, or other organism. Species differ from one another in at least one characteristic, and generally do not interbreed. In biology, species is a category that’s part of the scientific system for grouping together related plants, animals and other organisms (kingdom, phylum, class, order, family, genus, species).

spectrum: a series of colored bands of light diffracted and arranged in order of their wavelength–red, orange, yellow, green, blue, violet. A rainbow is an example of a spectrum.

spicule: a small needlelike structure of silicate or calcium carbonate supporting the soft tissue of certain invertebrates like sponges.

spinner dolphin: a species of small dolphin, which often spins in the air when it leaps.

sponges: a group of invertebrates with very simple bodies that spend their lives in one place. Some kinds form a tough, flexible skeleton full of holes or pores. People harvest these skeletons; they were the first sponges used for bathing and cleaning.

spore: a reproductive structure, formed without the union of sexual cells, which can give rise to a new organism. Fungi, algae and many other organisms produce spores rather than seeds.

spotted dolphin: a species of dolphin with spotted skin.

squarespot: a small, colorful fish from Pacific coral reefs.

squid: a soft-bodied marine animal with two long tentacles for catching food, eight or more shorter arms, and a streamlined body adapted for swimming quickly through open water. Squid are related to octopuses and cuttlefishes.

stinging cell (nematocyst): the stinging capsule on the tentacles of an anemone or jelly, which the animal uses to protect itself or to capture food.

stinging cell: Another word for nematocyst.

stipe: the stemlike part of a kelp plant connecting the holdfast to the fronds.

stocks: stocks of fish are fish populations–the total number of fish of each species.

stranded: washed up on shore.

subduction: the process in which one huge plate of the earth’s crust descends beneath another plate.

submarine canyon: a long, narrow, steep-walled undersea valley.

submersible: a submarine vehicle used in oceanographic studies.

subsidy: money paid by a government to encourage people do something the government believes is desirable. Many governments once offered subsidies to help people buy fishing boats.

substrate: the surface or material on which an organism lives–rock, sand, mud, pilings, shells.

sulfide: a compound of sulfur.

sulfur: a pale yellow, nonmetallic chemical element. Sulfur compounds often have a strong smell, like rotten eggs.

surfperches: a family of fishes with rounded bodies that live close to shore and feed in the rough water of the surf zone.

surf zone: the area of rough water next to the land, where ocean waves hit the shore.

suspension feeder: an animal that eats by filtering out tiny particles of organic material suspended in the water.

sustainable: able to last; able to continue into the future.

swarms: Jelly swarms happen when great aggregations of animals are brought together, blown by strong winds and currents.

swimbladder: a gas- or oil-filled sac found in many fishes. A swimbladder is like a float; without it, the fish would sink to the bottom if it stopped swimming.

swordfish: a large predatory fish with a long, swordlike bill at the tip of its snout. Swordfish are famous for their speed and strength. They’re also heavily fished for their meat.

symbiosis: A type of relationship between two organisms.

tentacle: Long, slender, flowing part of a jelly that contains stinging cells.

terrestrial: of the land; living on land.

tether: a long rope or leash that attaches two things together. The cable that attaches a submersible to a ship is called a tether.

thermocline: a zone where the temperature drops rapidly as you descend deeper into the water.

thorax: the chest region of a vertebrate animal, or the central segment of the body of an insect, crustacean or other arthropod.

tide: the daily rise and fall of sea level along a shore, caused by the pull of the moon and the sun on Earth’s oceans.

tidal channel: a channel where water rises and falls with the tides.

tide pool: a pool of water left along the shore as the tide level falls.

tilapia: a member of a group of plant-eating freshwater fishes native to Africa; they are easily raised in ponds.

transect: an area of land or seafloor sectioned off for particular study purposes, usually in the form of a long, continuous strip.

transformer: a device used to transfer electric energy from one circuit to another.

transparent: able to be seen through.

trawl: a funnel-shaped net towed through the ocean or along the seafloor to collect fishes and invertebrates.

trawler: a fishing boat that tows a trawl net.

trawling: fishing by towing a trawl net.

trout: a member of a group of long-bodied fishes related to salmon. Trout have been important food fish for people for centuries. Many trout species live their entire lives in fresh water, but some spend part of their lives in the sea and return to rivers to spawn.

tubeworm: any of a number of species of marine worms or wormlike animals that make a chimneylike tube to live in. In some species the tubes are leathery, in others hard and stony.

tuna: a group of large, sleek, predatory fishes that wander the open oceans of the world. Many species of tuna are important food fish for people.

tunicate: small, primitive chordate animals that live attached to rocks or to the seafloor. Many species of tunicate live in the intertidal zone, and some, like the predatory tunicate, live in the deep sea. Some tunicates are called “sea squirts” because they squirt water when disturbed.

turbidity currents: a quick-moving mixture of water and sediments that travels downslope, scouring the substrate and depositing sediments as it goes.

twilight zone: in the ocean, the midwater zone of dim light that lies between the sunlit zone and the completely dark, deeper zone.

understory: the vegetation that grows below the canopy of a forest.

upwelling: the movement of cold, nutrient-rich water from the ocean depths up toward the ocean surface.

urchin: a type of echinoderm invertebrate, related to sea stars, shaped like a ball and protected by long, sharp spines. Often called a “sea urchin.”

vegetarian: eating only plants (see herbivore).

vegetation: plants.

ventral: on or toward the belly or underside (opposite of dorsal).

vertebrate: an animal with a backbone. Fishes and people are both vertebrates.

vertical: up-and-down; in the up-and-down direction (opposite of horizontal).

vertical migration: an aquatic animal’s daily or seasonal movement up toward the water’s surface and back down to deeper water.

vestigial: nonfunctioning, a remnant of a body part that existed in a former species of an animal. Whales have tiny, vestigial hind legs buried deep in their bodies.

volcano limpet: a large limpet with a volcano-shaped shell; it prefers warm waters.

wahoo: a large fish that lives in the open ocean in warm parts of the Pacific.

Western Flyer: a ship used by researchers at the Monterey Bay Aquarium Research Institute that deploys a remotely operated vehicle (ROV) to videotape or collect deep sea animals or other scientific data.

wetland: a place where the soil is very wet and the habitat is part land, part water. Marshes, swamps, bogs and fens are different types of wetlands. Wetlands provide food and shelter to many kinds of animals.

whale: a large sea mammal that has smooth skin and breathes through a blowhole located on top of its head. The toothed whales, including sperm whales, orcas, dolphins and porpoises, have sharp teeth for catching fishes. The baleen whales, including the blue whale, gray whale and humpback, have flexible baleen fringes in their mouths for eating krill.

wharf: a structure built out over the water where boats can dock. A wharf is supported by heavy wooden or concrete pilings. The plural of wharf is “wharves.”

wobbegong: a coral-reef shark from Australia and the south Pacific, with spotted skin that makes it almost invisible among the coral.

wolf-eel: a long, eel-shaped fish with large teeth, most common in northern Pacific waters.

yellowfin tuna: one of the larger species of tuna, which has yellow markings on its fins and tail. Yellowfin live in warm, tropical waters. Much of the world’s canned tuna is yellowfin.

zonation: the distribution of the plants and animals in a community into recognizable zones.

zooplankton: animal plankton.

zooxanthellae: tiny, colorful algae that live in the tissues of coral. They use the energy from sunlight to produce nutrients, which they share with the coral.