I do follow a rule of thumb.  If it is a fish from seawater, then I will eat it, if it comes from a river, lake or reservoir, I will not.  But that is me.  And I do look at the fish before buying it do.

I only eat fish at restaurants located at sea shore places, the rest is at home.

This is my preference, I have no solid evidence to back this up, just heresay.

Nope. It's not really "safe" to eat seafood anywhere in the world since, correct me if I'm wrong, it all contains mercury. In China, you have more mercury than usual, and other pollutants. Despite the accepted Chinese wisdom , or lack thereof, pregnant women should avoid seafood at all costs.

The question you ask is impossible to answer with any degree of accuracy. The problem being that food production in China is so diverse and there are so many factors within the supply chain where product can become contaminated or malpractice can occur.  Sadly, that can be said for many other food and non food sectors too.

China is still one of the biggest seafood producing countries in the world. There are many companies that stick rigidly to international food safety standards such as HACCP, GMP and BRC. The product is regularly tested for harmful bacteria, moulds, viruses and other contaminants and pass with monotonous regularity. The premises undergo regular inspection by both Chinese and foreign quality system auditors. They supply both the export and domestic market with no problems whatsoever.

At the other end of the scale, there are thousands of smaller producers who cut many corners to make a basic living. Therein lies the problem. Restaurants and marketeers, retailers etc. have options to buy cheaper, more risky product. You have little chance to know where the product you are eating has come from.

It is the whole China food safety problem in a nutshell. 80% of food produced in China meets all necessary food safety standards. Above 99% exported from China passes international standards. But a vast mountain of food products are produced each year and even that 20% represents many thousands of tonnes in real terms.

This is where the numerous China derived food safety issues arise from. Controlling all of these smaller producers is a nightmare for any regulatory body let alone one with the inherent faults of the Chinese regulators.

In the morning, I almost get hit by speeding car. It happened at least twice a week on average.

OK, today I survived!

Lunch time, I am cooking Calamari Risotto: I got very small (young) calamari at the Open market in the morning. Bigger (older) calamari are too chewy, so when I see young ones, I am cooking.  

I was looking for Red Montepulciano at Metro, but line at register was too long, so I am drinking hong cha with Risotto.

What is safer: 'calamari' or 'walk in Dalian'?