回复: 圣河旁,秋渐近,风渐凉,钓鲤爽,
我怎么记得鲶鱼是catfish?还有,有人说鲶鱼是底层鱼,重金属严重。。。后来钓到就不吃了
关于圣河的鱼儿的污染程度,众说纷纭,关于那种鱼的污染严重些也是各有见解。
转帖一则仅供参考:
by John Symon
A press release by ice fishing company recently published in this newspaper (and elsewhere) suggested that waters of the St. Lawrence River around Montreal are clean and that fish caught around here thus are safe to eat. “The St. Lawrence River is therefore clean… and that’s not fishy! At least 53 different species of fish can be found in the river between Montréal and Sorel many of which are edible, such as walleye, burbot, bass, pike and perch,” reads part of that release. In fact, the Quebec government, Environment Canada, and Health Canada have issued guidelines on this subject and the reality is more complicated than it first seems.
Mercury concentrations increase going up the food chain
Image: courtesy of Environment Canada
It is important to understand that fish can be highly contaminated with pollutants even if the waters in which they live in are fairly clean. This can happen through the process of bioaccumulation reports Environment Canada in the web article “Mercury in the Food Chain.” That document describes how mercury can be up to 10,000,000 times more concentrated in the flesh of certain fish or birds (all near the top of the food chain) than it is the water where they live. Plant-eating fish tend to have much lower concentrations of mercury than do top predators (i.e. pike, musky, eels, otters, kingfishers). Bigger fish will probably also have higher concentrations of mercury than smaller fish of the same species.
Fish caught in areas of relatively clean water may have also spent time in other areas where the water is not so clean. And there are areas around Montreal Island with water quality issues. And sometimes pollutants can be airborne, contaminating seemingly pristine, remote lakes.
The Quebec Ministry of Sustainable Development’s online article entitled “Guide de consommation du poisson de pêche sportive en eau douce” lists mercury, PCBs, DDT, dioxins, Mirex, and furans as the principal contaminants that concern local fresh water fish. This document points to eels as being particularly contaminated with mercury, suggesting for the general population to eat as little eel as possible. Women who are pregnant, however, together with nursing babies and young children should not eat any eel. There is no such warning for any other species of fish found locally.
While mercury is not the only contaminant in fish, it is perhaps the one that has been most studied and best understood. And some mercury is naturally-occurring, but man-made pollution increases the amount of mercury in the environment. These documents point out that a human body can naturally eliminate mercury over time and the main danger is in eating too much contaminated fish over a short period of time. Again, it is women who are pregnant, nursing babies, and young children who are at most risk.
This reporter is not trying to frighten people away from eating fish caught locally, but merely trying to correct some possible misconceptions. It is also important to put this issue into perspective and realize that there are low levels of contamination in many foods bought in our supermarkets. This reporter also goes fishing with his son around Montreal Island and does not hesitate to eat certain fish caught at certain locations. Bass, perch, trout, and shad are my favourites. I also enjoy eating pike, which tends to have more mercury, but make a point of not eating another pike for many months afterwards. Let me further add that ice-fishing can be a lot of fun. I just hope that fishermen are aware of the guidelines…