You can read the full article here on SURGE Activism website written by Ed Winters, there you will also find all the sources of presented information. You can also watch Ed's very well presented video below.
FEW more things to add
Fatty fish are species of fish with oil in the soft tissues and in the body cavity around the intestine. Their fillets can contain up to 30 percent oil, but this value varies from species to species. Examples of fatty fish include small forage fish such as sardines, sledges and anchovies, other larger pelagic fish such as salmon, trout, tuna, swordfish and mackerel.
A study of 120 healthy middle-aged men and women examined the effects of increased consumption of fish and shells on mercury, arsenic, lead and cadmium levels in the blood. The researchers concluded that the concentrations of mercury, arsenic and lead in the blood increased significantly after 26 weeks of increased consumption in this healthy population. Mercury and arsenic concentrations did not pose health problems for this population, with the exception of lead, which was high and exceeded tolerable levels. The main physiologically adverse effects of too much lead in our body are neurotoxicity, gastrointestinal toxicity (GIT) and anemia.
Occasional eating of fish (for example, once a month or once every two weeks) should not cause us too much problems in our blood stream if we have a plant-rich diet. However, we should not ignore the consequences and dangers of consuming marine life that transmits zoonotic diseases, such as those caused by faecal leakage in animal agriculture areas and other industrial pollution.
From an environmental and ethical point of view, however, it is a completely different story. Just because it won't ruin our health doesn't mean it won't ruin something else. High fish consumption and commercial fishing are responsible for the suffering and death of up to 2.7 trillion marine animals each year, and are also responsible for the degradation and destruction of our oceans.
It must be added, however, that seafood is vital for the inhabitants of coastal villages and with the growing demand for marine life and illegal commercial fishing the fish stocks are constantly declining. Fish are an integral part of their lives and festive traditions and serve as a symbol of their prosperity, culture and heritage.
Consuming fish is not a necessity for people with a privileged lifestyle. So if we want to protect animals, our environment, our health and the inhabitants of coastal villages, whose livelihoods and lifestyles depend on fishing, it is time to leave the fish where they belong, in the oceans.