Cacophonous: Loud and noisy.

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

Calibrate: To check the accuracy of an instrument.

Camouflage: Colours 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.

Capsize: To turn over.

Carapace: In crustaceans, the 'shield' covering the upper surface of part of the body of various species e.g. the broad shield forming the upper body cover of crabs.

Cardiopulmonary resuscitation: Form of resuscitation used to keep a heart beating and sending oxygen to vital organs. Also called CPR.

Carnivore: A flesh eater, 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.

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

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

Catamarans: Twin-hulled sailing vessel.

Catchment: Describes the area of land which contributes runoff to a particular creek, river lake or ocean.

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.

Cellulose: A complex carbohydrate present in the cell walls of plant cells.

Celsius: Measurement of temperature.

Centripetal force: An outwardly pushing force. Think of a bucket swung around your head; the water in the bucket stays there because of the centripetal force.

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

Certificate level: Level of competency-based learning (AUS).

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

Chameleon: a lizard that can change colour to match its background.

Channel: the deepest part of a stream or harbour, where most of the water flows.

Charter boats: Ships with paying passengers.

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.

Chitin: Specialised protein found in hard skin.

Chlorofluorocarbons: Synthetic chemical gases used in aerosols, packaging and refrigeration.

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

Chloroplast: Cellular part of plants responsible for photosynthesis and containing photosynthetic pigments and enzymes.

Cholera: Infectious disease spread by specific micro-organisms in contaminated water.

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.

Ciguatera: Disease of humans caused by eating tropical fish containing toxins. These toxins are thought to come from blue-green algae.

Cilia: Small hair-like structures covering the body of animals.

Circulation: The movement of blood round the body which causes a pulse you can feel either in the neck or the wrist.

Cirri: Small, flexible appendages present on some invertebrates, including barnacles and annelids.

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.

Coastlines: Part of the mainland near the sea made from rock, sand or coral. Mostly vegetated. Under great threat from humans.

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.

Coelenteron: Hollow gut of animals belonging to phylum Coelenterata.

Cold fronts: When a cold air mass moves into or under a warm arm mass. Sometimes associated with strong winds but always with cold weather.

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.

Colonies: Refers to bacterial colonies that grow on a plate which, when counted, give an indication of sewage pollution. In birds, refers to places where they breed.

Commensalism: A form of symbiosis in which only one of the animals benefits from the relationship.

Commerce: General term referring to the business side of the marine industry.

Commercial fishers: Fishers who sell their fish.

Common property resource: Resource such as the sea that we all use.

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.

Compass: An instrument for determining directions relative to magnetic north.

Competent: Vocational education term. Refers to when you can actually perform a skill (usually unsupervised).

Compression: To push the chest down so as to stimulate the heart to contract and maintain a blood circulation to the brain.

Conservation: The practice of protecting nature from loss or damage.

Conserve: To keep in safe or sound state. Refers to seas, reefs, offshore islands, national parks and the animal and plants that live there.

Consumers: Those who use a commodity or service. Animals which eat others in the food chain.

Contaminated: Polluted - refers to water.

Continental crust: The earth's crust that includes both the continents and the continental shelves.

Continental ice: Ice composed of fresh water.

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 that slopes gradually from the exposed edge of a continent to where the drop-off to the deep seafloor begins.

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 shrimp like 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.

Core: Term used in marine vocational education to mean compulsory part of certificate course.

Corrosion: Process by which metals are eaten away by salt water and air.

Corrosive: Forces that cause the eating away of materials in sea water. Sea water is corrosive because it combines with air to eat away metals.

Corrugations: Rows of ridges.

Counter-current: A current flowing in a direction opposite to that of another current.

CPR: Cardiopulmonary resuscitation to maintain both oxygen and heart functions during resuscitation.

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.

Crest (surfing): The top of the wave.

Crustacean: An invertebrate animal with a hard shell and many jointed legs. Prawns, 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. It feeds on coral polyps.

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

Culling: Selective removal of animals for conservation purposes so other species can have food. Scientifically debatable process.

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

Cunjevoi: Animal found on rocky shores at low tide in sub-littoral zone. Has a notochord and feeds with a siphon action. Also called a sea squirt. Good bait.

Curator: Person in charge of a museum or exhibition.

Cutlets: Fish pieces cut into steaks.

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

Cyanobacteria: Blue-green algae. One species causes a red tide.

Cyclone: Tropical revolving storm. Caused by warm moist air rising quickly into low pressure systems in the southern hemisphere.