Fishing - eat your catch with care

Fish are an important part of a healthy diet. They are high in protein and other essential nutrients, low in saturated fat, and contain omega-3 fatty acids. In general, the benefits of eating fish greatly outweigh any risks.

That said, people who fish in some urban waterways need to be careful about eating their catch. The risks can be reduced by making sensible choices about the type and amount of fish you eat. If you fish, check whether any local advice applies to the waters you fish in, and contact your local authority for information if you are unsure.

Polluted waters and PCBs#

Over time, urban waterways can become polluted with chemicals, and fish can take up some of these chemicals into their bodies. Several chemicals can build up in fish, but one of the main concerns is a group of industrial chemicals called polychlorinated biphenyls (PCBs).

PCBs were used in industrial products from the 1930s to the 1970s. They have since been phased out, but they remain in the environment for a long time and can build up in the human body. If a person eats large amounts of contaminated fish, PCBs may affect their health.

People who are pregnant or who may become pregnant are the most likely to be affected, because PCBs in a mother’s body can affect the development of her unborn baby’s brain. Young children are also at increased risk.

Known health effects associated with PCBs include:

• Learning problems and developmental delay in children.
• Skin complaints such as acne or rashes.
• Liver problems.
• Changes to the immune system.
• Changes to the hormone system, including impaired functioning of the thyroid gland.

The potential health effects of low-level exposure to PCBs are complex and still need further investigation.

PCBs tend to concentrate in the fatty parts of a fish’s body. Eels have a higher fat content than most fish, so they tend to carry higher amounts of PCBs. Black bream also tend to be higher in PCBs than other species, while mullet tend to have comparatively lower levels.

Reducing the risks from your catch#

• People who are pregnant or may become pregnant, and children under 16 years, should limit eating caught fish to one serve per month.
• Everyone else should limit eating the fish they catch to four serves per month.
• These recommendations apply to 150 g serves. Weigh your fish portions so you do not exceed 150 g per serve.
• Try to eat smaller, younger fish, as these usually carry fewer pollutants than older, larger fish - but make sure they are within any legal size limits.
• Clean and cook fish properly. Remove the skin, fat and internal organs before cooking, as some chemicals concentrate in the fatty parts.
• Grill or bake fish rather than frying.

These precautions apply only to fish you catch from affected waters. They do not apply to shop-bought fish.

Fish from flood-affected waters#

Do not eat fish from flood waters or flood-impacted rivers, as water quality in these conditions can be poor.

PFAS in fish#

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of over 4,000 manufactured chemicals. They include perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS).

Products that have contained PFAS include carpets, non-stick cookware and, in the past, fire-fighting foams. Most people are exposed to low levels of PFAS, mainly through food or drinking water, and this is unlikely to be harmful to health.

Animal studies have shown some links between PFAS exposure and health effects, but there is no consistent evidence that PFAS are harmful to human health at the levels found in the environment. Testing of fish has shown varying PFAS concentrations, with some exceeding health-based guidance values for food. Because PFAS can persist for a long time in both the environment and the body, it is sensible to minimise exposure where possible as a precaution.

Shop-bought fish and mercury#

A well-balanced diet that includes fish has many benefits, including for heart health and for children’s growth and development. However, some fish can contain increased levels of mercury.

Mercury is a metal that can build up in the human body and damage the nervous system and kidneys. If a pregnant woman has too much mercury in her body, her child may be at risk of learning problems and developmental delays.

Generally, the mercury in most fish sold for food is not a health risk for healthy adults and children eaten in reasonable amounts. Predatory fish that are large and at the top of the food chain tend to contain more mercury. Pregnant women, women of child-bearing age and young children (under 6 years) should eat predatory fish such as shark or swordfish no more than once a fortnight. For everyone else, this is no more than once a week.

Health benefits of eating fish#

Eating fish once or twice a week can offer many benefits, including:

• Lowered blood pressure.
• Boosted levels of “good” blood cholesterol.
• Reduced risk of heart disease.
• Reduced risk of dementia.

Key points#

• In general, the benefits of eating fish greatly outweigh any risks.
• The risks of eating your catch can be reduced by making sensible choices about the type and amount of fish you eat.
• One of the main chemical concerns in some urban waterways is polychlorinated biphenyls (PCBs).
• Mercury can also remain in the environment for a long time.
• Young children are also at increased risk.

Where to get help#