I got this from GOOGLE, hope it helps. Kev
"The'cod worm', which is often found in cod, is also found in many other species. Its scientific name is Phocanema decipiens; other outdated scientific names are Porrocaecum decipiens or Terranova decipiens. It grows up to 4 cm long in fish, and varies in colour from creamy white to dark brown. It is frequently found in the flesh of fish, particularly in the belly flaps, where it often remains for long periods curled up and encased in a sac-like membrane produced by the fish tissue.
The life history of a parasitic round worm is complex. The adult lives in the stomach of a marine mammal, Phocanema in the grey seal and Anisakis mainly in dolphins, porpoises and whales. Eggs of the parasite pass into the sea with the mammal's excreta, and when the eggs hatch the microscopic larvae must invade a new host in order to develop. The larval worms of Anisakis are eaten by a small shrimplike crustacean, a euphausiid; the first host of Phocanema is a small isopod crustacean that lives on the sea bed.
When crustaceans infested with Anisakis or Phocanema are eaten by a fish the larval worms are released into its stomach. They then bore through the stomach wall and eventually become encased in the guts or in the flesh of the host fish. The life cycle of the parasite is completed when an infested fish is eaten by a suitable marine mammal.
Large fish tend to be more heavily infested by round worms than small fish of the same species. This is because large fish eat more, and therefore ingest greater numbers of parasites, and also because the larval worms, although inactive, can survive for a long time in fish, and therefore their numbers accumulate as the fish grows older.
There have been cases of human illness caused by the ingestion of live Phocanema or Anisakis larvae in countries where raw or lightly cured fish is commonly eaten. By 1980, there had been only one reported case of illness in the United Kingdom caused by larval round worms from fish; this is because in the UK fish products are normally cooked before consumption. Phocanema and Anisakis larvae are killed in 1 minute at a temperature of 60°C or over. In practice this means that cooking a fillet 3 cm thick for 10 minutes at 60°C will kill any worms present. The temperature of a cold smoking process, for example kippering, is not high enough to kill parasites, but in a commercial hot smoking process a high enough temperature is usually maintained for long enough to kill them. Freezing of fish at - 20°C for 60 hours kills all worms.
Anisakis larvae are resistant to salting; immersion in 80° brine, 21 per cent salt, for 10 days will kill all larvae, but in brine of lower strength they can survive for much longer. Anisakis is also resistant to marinating. When there is any doubt about whether Anisakis will survive a process it is safest to use frozen fish. The ability of Phocanema to withstand salting or marinating is not known, but it is probably similar to that of Anisakis.
Ill just have to fry everytime
