We know about the fish that were eaten in the period from bones which have been found during archaeological excavations. Some bones have been found whilst digging was being carried out, but most need soil samples to be washed through fine meshed sieves back in the laboratory. Some bones come from toilet pits and appear to have been chewed up before being swallowed. It has been possible to discover what kinds of fish were eaten by comparing the bones with those of fish today.
Evidence shows a variety of fish were eaten - herring, salmon and eel as well as some which are not eaten much today such as pike, perch and roach. They seem to have also eaten flounder, whiting, plaice, cod and brown trout too. Shellfish, especially oysters, mussels and cockles, seem to have formed part of many peoples diets. Fish was eaten fresh, but was also preserved for less plentiful times of year. This was done by salting, pickling, smoking and drying.
How were fish caught? In Ælfric's Colloquy the <a href="http://www.regia.org/fishing.htm">fisherman</a> explains his craft:
Master: How do you catch the Fish?
Fisherman: I board my boat and cast my net into the river; and throw in a hook and bait and baskets; and whatever I catch I take.
Master: What if the fish are unclean?
Fisherman: I throw the unclean ones away, and take the clean ones for food.
Master: Where do you sell your fish?
Fisherman: In the city.
Master: Who buys them?
Fisherman: The citizens. I can't catch as many as I can sell.
Master: Which fish do you catch?
Fisherman: Eels and pike, minnows and turbot, trout and lampreys and whatever swims in the water. Small fish.
Master: Why don't you fish in the sea?
Fisherman: Sometimes I do, but rarely, because it is a lot of rowing for me to the sea.
Master: What do you catch in the sea?
Fisherman: Herrings and salmon, porpoises and sturgeon, oysters and crabs, mussels, winkles, cockles, plaice and flounders and lobsters, and many similar things.
Master: Would you like to catch a whale?
Fisherman: Not me!
Fisherman: Because it is a risky business catching a whale. It's safer for me to go on the river with my boat, than to go hunting whales with many boats.
Master: Why so?
Fisherman: Because I prefer to catch a fish that I can kill, rather than a fish that can sink or kill not only me but also my companions with a single blow.
Master: Nevertheless, many catch whales and escape danger, and make great profit by it.
Fisherman: You are right, but I dare not because of my timid spirit.
It seems that river fish were caught in nets, hunted with fish-spears or even caught in wicker traps. Large sea fish were caught in nets which floated below the surface of the sea and others were caught with hooks and lines. Whales and dolphins were also hunted for their meat, as well as other useful products such as whalebone and fat. Interestingly enough, as porpoise were considered to be a fish, they were acceptable fare during Lent.