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Types of Seafood – Part One

Although there are hundreds of different types of seafood, and thousands of different ways to prepare the food, there are five main categories as identified by the International Standard Statistical Classification of Aquatic Animals and Plants and adopted by the Food and Agriculture Organisation. These categories contain several subgroups and then even more species within these, and are; fish, molluscs, crustaceans, other aquatic animals and aquatic plants. The data includes both seafood caught in the wild and those raised through the practice of aquaculture.

Fish

The most popular of the types of Seafood in terms of tonnes consumed fish can be split into five subgroups. The first of these is marine pelagic, which are fish that live and feed near the bottom of the sea and include fish such as; tuna, swordfish and smaller fish like herring and sardines. The next group are known as marine demersal and are very similar to the pelagic fish in terms of where they live and feed, however they are much less active than the pelagic fish and differ in their appearance by their white flesh, compared to the red flesh of the pelagic fish. The difference in colour of the flesh is due to the fact that the pelagic fish are more active than the demersal, and as such the red flesh is a characteristic of the more powerful swimming muscles that they need. Another group is the diadromous which are fish that inhabit fresh water and the sea and include fish such as salmon and eels.

The final sub group in the fish category is the freshwater fish, which – as their name suggests – inhabit fresh water like rivers and lakes. Some common examples of fresh water include carp, bass and trout. Due to their location fresh water fish find themselves being fish farmed more readily than their counterparts.

Molluscs

Molluscs are invertebrates with soft bodies, two of the subgroups are protected by a shell, whilst the third is not. The first of this group is the bivalves, which refers to the two hinged shells, such as; oysters, scallops and mussels. This subgroup is very popular, especially in finer dishes, they usually bury themselves on the seabed or against rocks and hard surfaces to keep themselves safe from predators. Oysters were favoured by the ancient Romans and are very popular in Ireland, where it is very normal to buy oysters as a bar snack to go with a pint of Guinness – this tradition doesn’t feature in the rest of the UK and can be quite a surprising combination to come across. Gastropods are the other category that have a protective shell, although this is in a single piece as opposed to the bivalves and popular gastropods include limpets and whelks. The final subgroup in this category are cephalopods, which don’t have a shell at all and are generally of higher intelligence than their two counterparts in this category. Octopus ad squid are both examples of this group which are eaten around the world, both of which require delicate preparation to be safely consumed.

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Seafood and Health

Seafood – in particular fish – has long been regarded as a staple part of a balanced diet, offering several health benefits. Despite its popularity many people do not know the full detail of these benefits or any information about the potentially negative impact of seafood on health. If people are aware of the potential risks, it is not always clear how that risk comes about and whether the risk is great enough to eliminate seafood from the diet.

Benefits of Eating Seafood

Some of the health benefits of Seafood are very well known, for instance amongst the health world it is common knowledge that the fat content, but the good fats – or the essential fats as they are known – are very prevalent. These essential fats – Omega-3s – are found in most fish, especially oily fish, and are an essential building block of the brain. The calorie content is also very low, which makes seafood very popular amongst the diet community. Another health benefit is that due to the low levels of saturated fat, seafood Is low in cholesterol, which is of course a very big concern for many people and a contributing factor in heart disease. Seafood is also high in protein and contains a high number of vitamins and minerals, including; zinc, iodine and B group vitamins – both of these benefits mean seafood is often part of an athletic diet, for those with high energy expenditures looking to replenish and repair the muscle, Sir Andy Murray, Britain’s most successful tennis player in the open era is known to eat fifty pieces of sushi every day due to the high demands of his tennis training.

Seafood has such a good reputation amongst the health world that government and health organisations recommend eating seafood twice a week in order to benefit from all of the healthy factors previously mentioned. However, there are known risks to eating too much seafood, and the risks are great enough for people to switch off from eating seafood altogether. The question that many people have to consider is whether the benefits outweigh the risks.

Potential Risks Associated with Seafood

One of the most common risks associated with eating Seafood is the consumption of mercury – due to human’s negative impact on oceans the levels of mercury are increasing within fish, largely because of toxins and environmental pollutants entering the oceans. This risk is greater when consuming fish that prey on other fish, as these larger fish, such as Shark and Swordfish, ingest mercury themselves and the mercury from the fish they eat, making it very prevalent in these fish. As mercury can have a negative impact on the developing nervous system, there is the fear the high levels could jeopardize the development of the brain in a foetus and young infants, which is why the NHS advised pregnant and nursing mothers to only eat low levels of oily fish such as salmon and to restrict their tuna intake to no more than four cans per week. It is clear that there are risks associated with eating seafood, however as long as the fish is cooked properly and consumption is within recommended levels, the health benefits outweigh the risks and seafood can be part of a healthy and balanced diet.