Fishing has long been a popular pastime for crew on board a vessel. But enjoying your catch could leave you feeling green around the gills for several reasons.
When deciding whether to fish for your supper, first check for any legal restrictions on fishing within that area. Many jurisdictions have fishing regulations and if crew are found to be in breach of these then they could be subject to criminal prosecution.
Once you have ascertained that it is legal to fish, consider the catch itself. Food poisoning from fish can be deadly if not recognised and treated quickly.
Poisoning from spoiled fish includes scombroid and ciguatera.
Scombroid poisoning is caused by fish which have not been properly refrigerated or preserved. This allows bacteria to act on compounds in the fish which then release histamine. This accounts for the allergic-type symptoms and explains why antihistamines help control symptoms.
Heat does not destroy the histamine so even well-cooked fish presents a risk.
The on-set of symptoms is fast, starting from 15 minutes to two hours following eating. Symptoms include flushing, rashes, sweating, diarrhoea and cramps. Most people recover, but additional reactions of swelling of the tongue and mouth as well as blurred vision can occur which can be fatal if proper care is not immediately provided.
When catching your own fish, refrigerate or freeze as soon as possible. If the fish tastes peppery, sharp, metallic or burns, do not eat it.
Ciguatera presents similar symptoms as scombroid but with added muscle pain, “hot-cold reversal” (hot items feel cold and vice versa), low blood pressure, blurred vision, hair loss and loss of nails. This may be followed by muscle paralysis, coma and eventual death through respiratory paralysis. If you survive, recovery can take months and symptoms may linger for years.
Ciguatera is produced by a type of algae associated with coral reefs. Small plant-eating fish eat the algae, then are in turn eaten by larger, predatory fish and the ciguatera from the algae accumulates up the food chain.
The highest concentrations of ciguatera are found in older, larger fish who are predatory in nature and have consumed many smaller fish throughout their lifetime (tuna, grouper, barracuda, snapper, jack, mackerel, triggerfish, marlin etc). The symptoms of poisoning can last for months or even years.
Appearance, taste and smell of the fish are not affected by ciguatera. Without these outward warning signs of contamination, the best prevention is not to eat fish caught on coral reefs and to avoid the larger predator fish. You can also minimise the chances of getting a dose of poisoning by not eating any of the guts, liver or gills of any fish.
If you do become symptomatic of fish poisoning, drink plenty of water and seek medical advice.
Author: Abbie Rudd
Senior Executive (Claims)