In the open sea, fish will be the main food source. There are some poisonous and dangerous ocean fish but, in general, when out of sight of land, fish are safe to eat. Nearer the shore there are fish that are both dangerous and poisonous to eat. There are some fish, such as the red snapper and barracuda, that are normally edible but poisonous when taken from the waters of atolls and reefs. Flying fish will even jump into your raft!
When fishing, do not handle the fishing line with bare hands and never wrap it around your hands or tie it to a life raft. The salt that adheres to it can make it a sharp cutting edge, an edge dangerous both to the raft and your hands. Wear gloves, if they are available, or use a cloth to handle fish and to avoid injury from sharp fins and gill covers.
In warm regions, gut and bleed fish immediately after catching them. Cut fish that you do not eat immediately into thin, narrow strips and hang them to dry. A well-dried fish stays edible for several days. Fish not cleaned and dried may spoil in half a day. Fish with dark meat are very prone to decomposition. If you do not eat them all immediately, do not eat any of the leftovers. Use the leftovers for bait.
Never eat fish that have pale, shiny gills; sunken eyes; flabby skin and flesh; or an unpleasant odor. Good fish show the opposite characteristics. Sea fish have a saltwater or clean fishy odor. Do not confuse eels with sea snakes that have an obviously scaly body and strongly compressed, paddle-shaped tail. Both eels and sea snakes are edible, but you must handle the latter with care because of their poisonous bites. The heart, blood, intestinal wall and liver of most fish are edible. Cook the intestines. Also edible are the partly digested smaller fish that you may find in the stomachs of large fish. In addition, sea turtles are edible.
Shark meat is a good source of food whether raw, dried or cooked. Shark meat spoils very rapidly due to the high concentration of urea in the blood; therefore, bleed it immediately and soak it in several changes of water. People prefer some shark species over others. Consider them all edible, except the Greenland shark whose flesh contains high quantities of vitamin A. Do not eat the livers, due to high vitamin A content.
You can use different materials to make fishing aids as described in the following paragraphs:.
Fishing line. Use pieces of tarpaulin or canvas. Unravel the threads and tie them together in short lengths in groups of three or more threads. Shoelaces and parachute suspension line also work well.
Fish hooks. No survivor at sea should be without fishing equipment but if you are, improvise hooks.
Fish lures. You can fashion lures by attaching a double hook to any shiny piece of metal.
Grapple. Use grapples to hook seaweed. You may shake crabs, shrimp or small fish out of the seaweed. These you may eat or use for bait. You may eat seaweed itself but only when you have plenty of drinking water. Improvise grapples from wood. Use a heavy piece of wood as the main shaft and lash three smaller pieces to the shaft as grapples.
Bait. You can use small fish as bait for larger ones. Scoop the small fish up with a net. If you don't have a net, make one from cloth of some type. Hold the net under the water and scoop upward. Use all the guts from birds and fish for bait. When using bait, try to keep it moving in the water to give it the appearance of being alive.
Helpful Fishing Hints
Your fishing should be successful if you remember the following important hints:
Be extremely careful with fish that have teeth and spines.
Cut a large fish loose, rather than risk capsizing the raft. Try to catch small, rather than large, fish.
Do not puncture your raft with hooks or other sharp instruments.
Do not fish when large sharks are in the area.
Watch for schools of fish; try to move close to these schools.
Fish at night using a light. The light attracts fish.
In the daytime, shade attracts some fish. You may find them under your raft.
Improvise a spear by tying a knife to an oar blade. This spear can help you catch larger fish but you must get them into the raft quickly or they will slip off the blade. Also, tie the knife very securely or you may lose it.
Always take care of your fishing equipment. Dry your fishing lines, clean and sharpen the hooks, and do not allow the hooks to stick into the fishing lines.
All birds are edible. Eat any birds you can catch. Sometimes birds may land on your raft, but usually they are cautious. You may be able to attract some birds by towing a bright piece of metal behind the raft. This will bring the bird within shooting range, provided you have a firearm.
If a bird lands within your reach, you may be able to catch it. If the birds do not land close enough or land on the other end of the raft, you may be able to catch them with a bird noose. Bait the center of the noose and wait for the bird to land. When the bird's feet are in the center of the noose, pull it tight.
Use all parts of the bird. Use the feathers for insulation, the entrails and feet for bait, and so on. Use your imagination.
Information courtesy of the U.S. Army Survival Manual