It depends on the region from where the sample is obtained

Dear Nabonita Pal,

Fish is very useful due to the presence of unsaturated fatty acids, including lauric, palmitic and myristic. Ingestion of fish prevents the formation of blood clots and protects the heart from the harmful effects of free radicals.

Dorada, Flounder, Salmon, Capelin and etc. very useful fish.

Is particularly rich in Vitamin B12 (pyridoxine), omega-3 fatty acids, vitamins A and D, and fat-soluble properties.

Regards, Shafagat

Fish is consumed as a food by many species, including humans. It has been an important source of protein and other nutrients for humans throughout recorded history.

Research over the past few decades has shown that the nutrients and minerals in fish, and particularly the omega-3 fatty acids found in pelagic fishes, are heart-friendly and can make improvements in brain development and reproduction. This has highlighted the role for fish in the functionality of the human body.[

Rationale:

•Selenium protects against mercury toxicity, and 16 of the 25 highest dietary sources of selenium are ocean fish

•If a fish contains higher levels of selenium than mercury, it is safe to eat

•Most species of commonly eaten fish in the U.S. have more selenium than mercury

•Fish are not significant sources of PCBs and dioxins when compared to meat, dairy or vegetables

•The benefits of eating fish regularly far outweigh the potential risks, which are neglible

•Pregnant mothers and young children should eat 2-3 servings of oily ocean fish each week

https://chriskresser.com/is-eating-fish-safe-a-lot-safer-than-not-eating-fish/

https://en.wikipedia.org/wiki/Fish_as_food

http://oehha.ca.gov/fish/so_cal/pdf_zip/SoCalAdvisoryl61809.pdf

general see food is not save to eat,Lowe level of havey metal maybe in baby fish like anchovy ,sardines

 The fish industry is worth around $200 billion annually, and its share is near 18% of the global meat market. It is generally safe, but some specific examples  of food poisoning are given

http://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre-travel-consultation/food-poisoning-from-marine-toxins

Fish industry is globalized now. Consumer do not knew the product which is consuming  by him, came from which region of country. Even fish is known for contaminations of Mercury and Arsenic but it is also contaminated by Cu, Cd, and Zn due to excess quantity.Beside that there are some toxins which are discovered and studied e.g.ciguatoxin or maitotoxin. What we think" Fish is safe" is because  its toxicity is not appeared suddenly. It is a good tonic with bad poisons.

Hudson Valley Region: Health Advice on Eating the Fish You Catch. This booklet provides advice on eating fish caught from Westchester, Rockland, Orange, Putnam, Dutchess, Ulster, Green, Columbia, Albany, Rensselaer, Schenectady, Saratoga and Washington counties. It includes maps of waters with advice and suggestions on where the entire family can eat up to four meals a month of caught fish.

http://www.health.ny.gov/environmental/outdoors/fish/health_advisories/

As for the Lebanese shore, it is highly contaminated, so eating fresh fish is risky. This is why lots of frozen fish are imported. Otherwise, no discussion about the benefits of eating fish as a balanced meal.

Consumption of fish and other seafood is also important for foetal development, including for the foetus’ growth and neurological development. It is believed that the marine n-3 fatty acids play an especially important role in the health-promoting effects of fish.

http://www.vkm.no/dav/83cf7bd765.pdf

Marine fish is the best source of omega three fatty acids, Fish oils are the only concentrated source of eicosapentaenoic acid  and docosahexaenoic acid. These are essential fats. But as per the concern healthy and safe, from which site the fishes are collected, and its very difficult to say that what kinds of migration patterns in that fishes. weather they are visiting to polluted site or not. so biochemical testing is the best way to see this parameters.

I strongly agree the point of Dr. Abhijit Mitra.

It depends on the region from where the sample is obtained is healthy or polluted as like Mitra sir told

Consumption of marine fishes is not new things. Most of the people who are living at the coastal regions live on seafood. However, one should avoid marine fishes collected from contaminated areas especially where extensive shipping activities are going on. Apart from shipping activities there are some areas where waste materials are discharged thereby contaminate the coastal water to a great extent. So consumption marine fishes collected from the contaminated areas are not recommended.

It's more complex than we think depending on local economic, ecological, geological, regulatory and other factors. In general, avoide consuming top trophic level and fish from contaminated areas/catchments. Pay attention to local/national fish consumption advisories. 

Not only the area of origin is important, but we need to consider also the size and the life spam of fish. In fact,it is well known that in marine fish mercury can constitute a concern for human health, cause it  is mainly present in the toxic form of methylmercury.  Due to the bio accumulation and biomagnification of this element in the food chain, large predatory fish (such as swordfish and tuna) contain higher levels of methylmercury than other species of fish.

It depends upon many factors:

-The localization of collecting area regarding to the pollution sources : pollutant's charge and nature,....

- The kind of fish species related especially to 2 parameters, size and food regime

- The quality of surrounding waters since it is the fish habitat ........

Marine fishes are safe to eat  and it lalso depends on the area where  fishes are caught. If fishes are caught from coastal area which are subjected to anthropogenic influnces . Overall, marine fishes are good

Sorry, Chand

but as I already wrote, the safety of the fish depends on many factors, and marine fish such as swordfish  reported on too high levels of mercury in their flesh.

The marine fish species most vulnerable of having too much mercury are predatory such as swordfish and shark, in particular larger and older specimens, as documented by RASFF - Food and Feed Safety Alerts. In the last years, 124 notifications were done, concerning the presence of mercury in fish exceeding the maximum limits set by EU Regulations

regards

stefania 

The consumption of marine fishes is absolutely safe if they are collected from the regions not contaminated with any toxic substances like cadmium, mercury, lead, copper, chromium, manganese, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) , polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzo-furans (PCDFs), highly persistent organochlorine pesticides (e.g. DDT, HCH, Chlordane, Hepox, heptaclor, aldrin, dieldrin, endrine ) etc. The major concern now-a-days is of marine pollution due to extensive shipping activities as well as dumping of waste materials into the marine aquatic ecosystem from the industries as well as from the cities. Thus the accumulation of the residues of highly toxic contaminants by the marine organisms can be bio-magnified to a higher level through the trophic transfer from the lower trophic levels to higher trophic levels. In view of this it is indeed of a major global concern for protection of the marine environment.

mostly unsafe when caught from coastal zone

Fishes  and classified wild and farmed fishes. Wild marine fishes  are caught from coastal, off shore and deep sea fishes. Fish harvested from coastal area are  not safe since which region are subjected to  man made  and industrial action. It is true.   As far as  fish consumption concerned , cooked wild fish in high temperature would be fine  since all micro, macro parasites are distroyed. Its depends on the region . Wild fishes harvested from  ocean from industrial world may be subjected for screening for heavymetals and toxic stuff . I may say  eating wild fish safe when cooked or microwave cooking.

Dear Nabonita,

Here are the latest research papers about this topic.

Best regards

SM Najim

http://onlinelibrary.wiley.com/doi/10.1002/jsfa.7360/pdf

http://onlinelibrary.wiley.com/doi/10.1002/jsfa.7360/abstract

http://www.omicsonline.org/open-access/assessment-of-heavy-metals-in-some-marine-fish-species-relevant-to-their-concentration-in-water-and-sediment-from-coastal-waters-of-ondo-state-nigeria-2155-9910-1000163.pdf

http://link.springer.com/article/10.1007/s10646-015-1451-7

http://scholar.sun.ac.za/bitstream/handle/10019.1/97964/bosch_status_2015.pdf?sequence=1