Coral Reef

Coral Reef
Richard Ling <wikipedia@rling.com>, CC BY-SA 3.0, Wikimedia Commons

Warm, clear, shallow sea built up by corals into walls and gardens of colour. From a boat it shows as bands of turquoise, green and dark blue; underwater it crackles with the sound of shrimps and parrotfish crunching coral, and at low tide the exposed reef smells of salt and sun-baked weed. Fish of every shape and colour crowd it, with turtles, rays, octopuses and the sharks that patrol its edges. People fish it, dive it for pearls and shells, and live on the islands it shelters behind its walls. It is sharp enough to tear a hull and a danger to any ship that does not know the passes, and some of its creatures sting or poison. The Great Barrier Reef, off the coast of Australia, is the largest reef of this kind.

Hear it

For the table

Ground
At sea: Sailing ship: 77 km a day, Warship: 96 km a day, Galley: 154 km a day, Longship: 115 km a day, Dhow: 223 km a day, Junk: 223 km a day, Steamship: 444 km a day, Ironclad: 401 km a day, Ocean liner: 934 km a day, Cargo ship: 667 km a day, Sailing yacht: 266 km a day, Survey craft: 888 km a day, Submersible: 355 km a day
Water
scarce
Foraging
rich

Hazards

  • Reefs and shoals. Rock or coral a fathom under the surface, a sandbank that moved since the chart was drawn. A ship that strikes may float off at the next tide, or open her hull.
  • Rain squall. A black wall of rain walks across the water and swallows the ship. For an hour the bow cannot be seen from the stern.
  • Becalmed. Not a breath of wind. The sails hang, the sea turns to oil, the sun beats on the deck and the water casks go down while the ship goes nowhere.
  • Waterspout. A grey funnel drops from a squall cloud to the sea and walks across the water, roaring. It can strip a ship’s rigging in a moment.
  • Water running low. The casks are low, or one has gone foul. Sea water only makes thirst worse; the crew is put on short water and watches the sky for rain.
  • Going under. A wave breaks over a swimmer, a diver stays down too long, a sinking hull drags someone with it. Air runs out faster than anyone thinks.
  • Man overboard. A green sea sweeps the deck, or a foot slips at the rail, and someone is in the water. By the time the ship comes about, the swimmer is a dot among the waves.

D&D 5e

Plays as
waterborne, by the ship pace at most
Checks
forage: Survival DC 15 · find the way: DC 10 · search: DC 15
Creatures are spotted at
6d6 × 10 ft
  • Reefs and shoals. (House rule) House rule: the lookout makes a Wisdom (Perception) check, DC 15 by day, 20 at night or in rain. On a failure the ship strikes: it takes 4d10 Bludgeoning damage (reduced by its damage threshold as usual) and stops until the crew warps it off, about an hour of work per 10 damage taken.
  • Rain squall. Heavy rain makes everything in it Lightly Obscured, gives Disadvantage on all Wisdom (Perception) checks and puts out open flames.
  • Becalmed. In a dead calm a ship cannot move under sail: it must be rowed, or it lies still. A ship that cannot be rowed makes no way that day.
  • Waterspout. (House rule) House rule: a ship that cannot get out of its path is hit. Everyone on deck makes a DC 15 Strength saving throw or takes 3d8 Bludgeoning damage and is thrown across the deck, or overboard on a d6 roll of 1 to 3. The ship takes 4d10 Bludgeoning damage and moves at half speed until its rigging is repaired.
  • Water running low. A Medium creature needs about 4 litres (1 gallon) of water a day. Drinking less than half of it brings 1 Exhaustion level at the end of the day, which does not go until a full day’s water is drunk.
  • Going under. A creature holds its breath for 1 + its Constitution modifier minutes (at least 30 seconds). After that it gains 1 Exhaustion level at the end of each of its turns until it can breathe; it then loses all the Exhaustion it gained this way.
  • Man overboard. Swimming costs 1 extra foot of movement for each foot moved (none with a Swim Speed). In rough water the GM may ask a DC 15 Strength (Athletics) check to move at all.

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

Adventure hooks

  1. A pearl diver knows a pass through the reef that no chart shows, and a pirate captain has taken her son to make her guide his ship through. She wants the ship to break on the coral, with her son off it first.
  2. Some fishermen have started stunning fish with poison, and the reef is turning white. The elders want it stopped; the fishermen say the merchants who buy live fish leave them no choice, and name the merchants.
  3. Once a year, on a calm night after the full moon, the reef spawns and the sea smells of fruit. An old woman wants to be rowed out to see it one last time, and she wants to be put in the water.
  4. Divers hired to salvage a ship that broke on the reef keep bringing up lumps of coral grown around coins. Every lump is shaped like a closed hand, and the captain who hired them has stopped sleeping.

What grows here

  • Coconut Palm (tree). A palm up to 30 m tall that grows wild on sandy, salty tropical shores and coral atolls; its floating nuts drift across the sea, and Austronesian voyagers carried it on their sea voyages. A tree gives up to 75 nuts a year, and fruits for some seventy years. Green nuts hold a drink, ripe ones white flesh, milk and oil; the husk gives coir for ropes and mats, the fronds thatch roofs, and its sap makes palm wine or sugar. Climbers who pick the nuts risk injury or death from falls. Gives: Coconut, Coir, Coconut Frond.
  • Enhalus (grass). A large seagrass of the tropical Indian and western Pacific Oceans, from the Red Sea and Mozambique to Papua New Guinea, with strap leaves 30 to 150 cm long on thick rhizomes anchored in mud, sand flats and coral ground, mostly just above the low spring-tide line and down to 4 m. Its leaves make up much of the shallow seagrass meadows, often mixed with Thalassia hemprichii, and give room to the small life that grows on them. It is the only seagrass pollinated at the surface: the male flowers break off and float until they reach a female flower, and the round fruit, 4 to 6 cm across, is drawn back under water to ripen.
  • Turtle Grass (grass). A seagrass of the Caribbean and the Gulf of Mexico with ribbon leaves up to 30 cm long, rooted by rhizomes buried in the sand. It carpets calm, salty lagoons from the low-tide line down to about 30 m, on muddy sand, coarse sand and clay. Its meadows shelter young fish and feed turtles, parrotfish, surgeonfish and sea urchins; people use it only in the aquarium trade.
  • Elkhorn Sea Moss (seaweed). A red seaweed, dark greenish brown to deep purple, up to about 2 m tall with branches 1 to 2 cm thick, that grows loosely attached to broken coral on the reef flats and reef edges of the tropical seas, 1 to 17 m deep, and can form drifting mats. It doubles its mass in fifteen days and is farmed on rope lines over shallow reefs from the Philippines, Indonesia and Malaysia to Tanzania; it is one of the chief sources of carrageenan and makes a jelly-like dessert. Brought to Kāneʻohe Bay in Hawaii in 1974 for farming, it spread over the reef and outcompetes the native species, and native urchins have been set on it to graze it back. Gives: Elkhorn Sea Moss.
  • Ogo (seaweed). Gracilaria is a large genus of red seaweeds of warm seas, which cannot bear water below 10 °C and are most varied in the western Pacific. They are eaten across Asia and the Pacific: ogo in Hawaiian poke, gulaman jelly in the Philippines, and soup with coconut cream and lime in Sri Lanka; they are also eaten in Korea, and in Jamaica the weed is called Irish moss. Over 90% of the world's agar, a vegetable jelly, comes from them. On Guam, deaths followed meals of it, most likely from toxic blue-green algae growing on the weed. Gives: Ogo.
  • Sea Grapes (seaweed). A green seaweed of the coasts of Southeast Asia, Oceania and East Asia, up to 30 cm long, covered in tiny bubbles like a miniature bunch of grapes. The bubbles burst in the mouth with a taste of the sea. It is eaten raw, alone or in salads: lato in the Philippines, umibudo in Okinawa. Farmed in the Philippines since the 1950s, later in Japan, Vietnam, Taiwan and China. Gives: Sea Grapes.

Animals

Creatures

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

To gather

Caribbean Spiny Lobster Meat, Coconut, Coir, Coconut Frond, Day Octopus Meat, Elkhorn Sea Moss, Loggerhead Turtle Meat, Ogo, Sea Grapes, Coconut Crab Meat, Dugong Meat, Dugong Oil, Dugong Tusk, Giant Clam Muscle, Calipee, Conch Meat, Queen Conch Shell, Trepang, Giant Clam Shell, Tortoiseshell, Black Pearl, Snake Venom, Concentrated Venom

Nearby biomes

Coastal Shelf, Kelp Forest, Open Ocean, Deep Sea

Open it in Biomes — MGS Toolbox